Cognitive Psychology Textbook Notes

*Chapter 1 – Introduction to Cognitive Psychology - Cognitive psychology is the branch of psychology concerned with the scientific study of the

mind Cognitive Psychology: Studying the Mind What is in the mind?

- The mind’s role in memory, problem solving, and making decisions, are related to the following definition of the mind: (1) The mind creates and controls mental functions such as perception, attention, memory, emotions, language, deciding, thinking, and reasoning

o This definition reflects the mind’s central role in determining our various mental abilities o This definition indicates different types of cognitions

- Cognition is the mental processes such as perception attention, memory, and so on, that are what the mind does

- (2) The mind is a system that creates representations of the world so that we can act within it to achieve our goals

o This definition reflects the mind’s importance for functioning and survival, and also provides the beginnings of a description of how the mind achieves these ends

o This definition indicates something about how the mind operates (it creates representations) and its function (it enables us to act and to achieve goals)

- Saying that the mind creates cognition and is important for functioning and survival tells us what the mind does but not how it achieves what it does

Studying the mind: Early work in cognitive psychology

- In the 1800s, 9deas about the mind were dominated by the belief that it is not possible to study in the mind

- One reason given was that it is not possible for the mind to study itself, but there were other reasons as well, including the idea that the properties of the mind simply cannot be measured

- Dutch physiologist Franciscus Donders, who in 1868, eleven years before the founding of the first laboratory of scientific psychology, did on of the first experiments that today would be called a cognitive psychology experiment

- “Cognitive psychology” was not coined until 1967 Donders’s Pioneering Experiment: How long does it take to make a decision?

- Donders was interested in determining how long it takes for a person to make a decision - He determined this by measuring reaction time - Reaction time is how long it takes to respond to presentation of a stimulus - In the first part of his experiment, he asked his participants to press a button upon presentation

of a light. This is called a simple reaction time task - In the second part of the experiment, he made the task more difficult by presenting two lights,

one on the left, and one of the right o The participants’ task in this part of the experiment was to push one button when the

light on the left was illuminated and another button when the light on the right was illuminated. This is called a choice reaction time task

- In the simple reaction time task (See Figure 1.3a, page 7), presenting the stimulus (the light) causes a mental response (perceiving the light), which leads to a behavioural response (pushing the button). The reaction time (dashed line) is the time between presentation of the stimulus and the behavioural response.

- In the choice reaction time task (See Figure 1.3b, page 7), it shows that the mental response includes not only perceiving the light but also deciding which button to push

- Donders reasoned that choice reaction time would be longer because of the additional time it takes to make the decision, and that the difference in reaction time between the simple and choice conditions would indicate how long it took to make the decision

- Donder’s experiment is importance because o (1) it was one of the first cognitive psychology experiments and o (2) because it illustrates something extremely significant about studying the mind:

Mental responses (perceiving the light and deciding which button to push, in this example) cannot be measured directly, but must be inferred from behaviour

- The dashed lines indicate that when Donders measured the reaction time, he was measuring the relationship between the presentation of the stimulus and the participant’s response

- He did not measure the mental response directly, but inferred how long it took from the reaction times

- The fact that mental responses can’t be measured directly, but must be inferred from observing behaviour, is a principle for this experiment and for all research in cognitive psychology

Ebbinghaus’s Memory Experiment: What is the time-course of forgetting?

- Hermann Ebbinghaus was interested in determining the nature of memory and forgetting—specifically, how information that is learned is lost over time

- He presented nonsense syllables such as DAX, QEH, LUH, and ZIF to himself one at a time, using a device called a memory drum (modern cognitive psychologists would use a computer)

- He used nonsense syllables so that his memory would not be influenced by the meaning of a particular word

- The first time through the list, he looked at each syllable one at a time and tried to learn them in order.

- The second time through, his task was to begin by remembering the first syllable on the list, look at it in the memory drum to see if he was correct, then remember the second syllable, check to see if he was correct, and so on

- He repeated the procedure, going through the list and trying to remember each syllable in turn, until he was able to go through the list without making any errors

o He noted the number of trials it took him to do this - After learning a list, Ebbinghaus waited, for delays ranging from almost immediately after

learning the list to 31 days - He then repeated the above procedure for each list and noted how many trials it took him to

remember all of the syllables without any errors - He used the savings method to analyze his results, by calculating the saving by subtracting the

number of trials needed to learn the list after a delay from the number of trials it took to learn the list the first.

- He then calculated a savings score for each delay interval, using: o SAVINGS = [(Initial repetitions) – (Relearning repetitions/Initial repetition] x 100

- Ebbinghaus found that the savings were greater for short intervals than for long o Ex. After a short interval it may have taken 3 trials to relearn the list. If it had taken him

9 trials to learn the list the first time, then the savings score would be 67% o SAVINGS = [(9-3)/9] x 100 = 67 o After longer intervals, the score would be less (6 trials for relearning = 33%)

- Ebbinghaus’s “saving curve” shows savings as a function of retention interval

- The curve indicates that memory drops rapidly for the first 2 days after the initial learning and then levels off

- This curve is important because it demonstrated that memory could be quantified and that functions like the forgetting curve could be used to describe a property of the mind—in this case, the ability to retain information

Wundt’s Psychology Laboratory: Structuralism and Analytic Introspection

- In 1879, Wilhelm Wundt founded the first laboratory of scientific psychology at the University of Leipzig in Germany, with the goal of studying the mind scientifically

- Wundt’s approach, which dominated psychology in the later 1800s and early 1900s, was called structuralism

- According to structuralism, our overall experience is determined by combing basic elements of experience the structuralists called sensations

- Wundt wanted to create a “periodic table of the mind,” which would include all of the basic sensations involved in creating experience

- Wundt thought he could achieve this by using analytic introspection - Analytic introspection is a technique in which trained participants describe their experiences

and thought processes in response to stimuli o Ex. In one experiment, Wundt asked participants to describe their experience of hearing

a five-note chord played on the piano o Wundt was interested in whether they heard the five notes as a single unit of if they

were able to hear the individual notes William James: Principles of Psychology

- William James is one of the early American psychologists who taught Harvard’s first psychology course and made significant observations about the mind in his textbook, Principles of Psychology

- James’s observations were based not on the results of experiments, but on introspections about the operation of his own mind

- One of the major forces that caused psychology to reject the study of mental processes was a negative reaction to the technique of analytic introspection

Abandoning the Study of the Mind

- Research in many early departments of psychology was conducted in the tradition of Wundt’s laboratory, using analytic introspection to reveal hidden mental processes

Watson founds Behaviourism

- Watson became dissatisfied with the method of analytic introspection - His problems with this method were:

o (1) it produced extremely variable results from person to person, and o (2) these results were difficult to verify because they were interpreted in terms of

invisible inner mental processes - In response to what he perceived to be deficiencies in analytic introspection, Watson proposed

a new approach called behaviourism - Behaviourism: the approach to psychology which states that observable behaviour provides the

inly valid data for psychology. A consequence of this idea is that consciousness and unobservable mental processes are not considered worthy of study by psychologists

- Watson’s goal was to eliminate the mind as a topic of study in psychology and replace it with the stud of directly observable behaviour

- Thus, the focus shifted from the mind as the topic of study to behaviour (with no reference to the mind) as the topic

- Watson’s most famous experiment was the “little Albert experiment,” in which Watson and Rosalie Rayner subjected Albert, a 9-month-old-boy, to a loud noise every time a rat (which Albert had originally liked) came close to the child

- After a few pairings of the nose with the rat, Albert reacted to the rat by crawling away as rapidly as possible

- Watson’s ideas are associated with classical condition - Classical conditioning is how pairing one stimulus (such as a loud noise presented to Albert)

with another, previously neutral stimulus (such as the rat) causes changes in the response to the neutral stimulus

- Watson’s inspiration for this experiment is from Ivan Pavlov’s research in classical conditioning in dogs

- Watson’s used classical conditioning to argue that behaviour can be analyzed without any reference to the mind

o What was going on in the mind of Little Albert was irrelevant Skinner’s Operant Conditioning

- B.F. Skinner introduced operant conditioning - Operant conditioning focused on how behaviour is strengthened by the presentation of positive

reinforcers, such as food or social approval (or withdrawal of negative reinforcers, such as a shock or social rejection)

o Ex. Skinner showed that reinforcing a rat with food for pressing a bar maintained or increased the rat’s rate of bar pressing

- Like Watson, Skinner was not interested in what was happening in the mind, but focused solely on determining the relationship between stimuli and responses

- The idea that behaviour can be understood by studying stimulus-response relationships influenced an entire generation of psychologists and dominated psychology in the United States from the 1940s through the 1960s

Setting the stage for the re-emergence of the mind in psychology - Edward Chance Tolman called himself a behaviourist because his focus was on measuring

behaviour, but in reality e was one of the early cognitive psychologists, because he used behaviour to infer mental processes

- In one of his experiments, Tolman placed a rat in a maze (See Figure 1.8,page 11) - Initially the rat explored the maze, running up and down each of the alleys - After this initial period of exploration, the rat was placed at A and food was placed at B, and the

rat quickly learned to turn right at the intersection to obtain the food - However, when Tolman placed the rat at C, at the intersection, the rat turned left to reach the

food at B - Tolman’s explanation of this result was that when the rat initially experienced the maze it was

developing a cognitive map - Cognitive map is a conception of the maze’s layout - Thus, even though the rat had previously learned to turn right, when the rat was placed at C, it

used its map to turn left at the intersection to reach the food at B

- Tolman’s use of the word cognitive, and the idea that something other than stimulus-response connections might be occurring in the rat’s mind, placed Tolman outside of mainstream behaviourism

- For most American psychologists in the 1940s, the use of the term cognitive was difficult to accept because it violated the behaviourists’ idea that internal processes, such as thinking or maps in the head, were not acceptable topics to study

- In his book, Verbal Behaviour, Skinner argued that children learn language though operant conditioning

- According to this idea, children imitate speech that they hear and repeat correct speech because it is rewarded

- But Noam Chomsky, a linguist, pointed out that children say many sentences that have never been rewarded by parents (i.e. “I hate you, Mommy”), and that during the normal course of language development, they go through a stage in which they use incorrect grammar, such as “the boy hitted the ball,” even though this incorrect grammar may never have been reinforced

- Chomsky saw language development as being determined not by imitation or reinforcement, but by an inborn biological program that holds across cultures

- Other psychologists began to realize that to understand complex cognitive behaviours, it is necessary not only to measure observable behaviour, but also to consider what this behaviour tells us about how the mind works

The rebirth of the study of the mind

- The decade of the 1950s is generally recognized as the beginning of the cognitive revolution - The Cognitive revolution is a shift in psychology from the behaviourist’s stimulus-response

relationship to an approach whose main trust was to understand the operation of the mind - Information-processing approach is an approach that traces the sequence of mental operations

involved in cognition - One of the events that inspired psychologists to think of the mind in terms of information

processing was a newly introduced device called the digital computer Introduction of the Digital Computer Flow Diagrams for Digital Computers

- One of the characteristics of computers that captured the attention of psychologists in the 1950s was that they processed information in stages

o Ex. Information is received by an “input processor” and is then stored in a “memory unit” before it is processed by an “arithmetic unit,” which then creates the computer’s output

- Using this stage approach as their inspiration, some psychologists proposed the then-revolutionary idea that the operation of the mind could also be described as occurring in a number of stages

- One of the first experiment influence by this new way of thinking about the mind involved studying how well people are able to pay attention to only some information when a lot of information is being present at the same time

Flow Diagrams for the Mind

- Beginning in the 1950s, a number of researchers became interested in describing how well the mind can deal with incoming information

- In one experiment, by British psychologist Colin Cherry, participants were presented with two messages simultaneously, one to the left ear and one to the right (See figure 1.10, page 13), and were told to focus their attention on one of the messages (called the attended message) and to ignore the other one (called the unattended message)

- The results of this experiment is that people could focus their attention on the message presented to one ear, and when they did, they were aware of little of the message being presented to the other, unattended ear

- This result led British psychologist, Donald Broadbent, to propose the first flow diagram of the mind

- This diagram represented what happens in a person’s mind as he or she directs attention to one stimulus in the environment

- This flow diagram is notable because it was the first to depict the mind as processing information in a sequence of stakes

o Applied to the attention experiments, “input” would be the sounds entering the person’s ears; the “filter” lets through only the part of the input to which the person is attending, and the “detector” records the information that gets through the filter

- Broadbent’s flow diagram provided a way to analyze the operation of the mind in terms of a sequence of processing stages and proposed a model that could be tested by further experiments

Conferences on Artificial Intelligence and Information Theory

- John McCarthy wondered if it be possible to program computer to mimic the operation of the human mind

- The Summer Research Project on Artificial Intelligence, was the first use of the term artificial intelligence

- Artificial intelligence is the ability of a computer to perform tasks usually associated with human intelligence

- Herb Simon and Alan Newell weren’t at the conference because they were busy trying to create the artificial intelligence machine that McCarthy had envisioned

- Simon and Newell’s goal was to create a computer program that could create proofs for problems in logic—something that up until then had only been achieved by humans

- Newell and Simon succeeded in creating the program, which they called the logic theorist - The logic theorist was able to create proofs of mathematical theorems that involve principles of

logic too complex to describe - This program, although primitive compared to modern artificial intelligence programs, was a

real “thinking machine” because it did more than simply process numbers—it used humanlike reasoning processes to solve problems

- George Miller presented the idea that idea that there are limits to the human’s ability to process information—that the information processing of human mind is limited to about 7 items

- Miller’s basic principle that there are limits to the amount of information we can take in and remember was an important idea

- It wasn’t until 1967 that Ulrich Neisser published a textbook with the title Cognitive Psychology - Neisser’s textbook coined the termed cognitive psychology and emphasized the information-

processing approach to studying the mind Researching the Mind

- Cognitive psychologists use both behavioural and physiological approaches to studying the operation of the mind

Memory Consolidation from a Behavioural Perspective - Memory consolidation is the process by which experiences or information that has entered the

memory system becomes strengthened so it is resistant to interference caused by trauma or other events

- Memory consolidation dates back to German psychologists Georg Muller and Alfons Pilzecker has two groups of participants each learn two lists of nonsense syllables

- The “immediate” group learned one list and were then asked to immediately learn a second list - The “delay” group learned the first list and then waited 6 minutes before learning the second list - When recall for the first list was then measured, participants in the delay group remembered

48% of the syllables, but participants in the immediate group remembered only 28% of the syllables

- Apparently, immediately presenting the second list to the immediate group interrupted the forming of a stable memory for the first list—the process that came to be called consolidation

- Steffan Gais had high school students learn a list of 24 pairs of English-German vocabulary words - The “sleep group” studied the words and then went to sleep within 3 hours - The “awake group” studied the words and remained awake for 10 hours before getting a night’s

sleep - The results of the experiment indicate that students in the sleep group forgot much less

material than the students in the awake group Memory Consolidation from a Physiological Perspective

- Modern researchers, armed with techniques for measuring physiological processes have begun to determine how consolidation involve processes in the brain

o Ex. Louis Flexner and coworkers did an experiment in which they showed that injecting a chemical that inhibits the synthesis of proteins in rats eliminates formation of memories

o This suggests that interference, such as that experienced by the football player, may disrupt chemical reactions that are necessary for consolidation

- Flexner’s study provides information about how consolidation might operate at the molecular level involved in protein synthesis

- Gais and coworkers carried out another experiment, in which participants learned word pairs and then were tested two days later

- This time, in addition to measuring memory, Gais measured brain activity, using brain imaging technique called fMRI

- He measured this activity first as participants were learning the word pairs and again as they were tested two days later

- Figure 1.15 (page 16) shows that the activity of the hypothalamus, a structure deep in the brain that is known to be involved in the storage of new memories, increased from learning to test for the sleep group but decreased from learning to test for the awake group

- Gais concluded from this result that immediate sleep helps strengthen the memory trace in the hypothalamus

Models of the Mind

- A model can be a representation of something, as a model car or airplane represents the appearance of a real car or airplane

- Models can also illustrate how something works, and in cognitive psychology models are generally used to represent how information is processed by the mind

o Ex. Broadbent’s flow diagram is a model of how a person processes information to selectively attend to one message out of many

- One advantage of models is that they often make a complicated system easier to understand - One of the ways that models provide “starting points” is by helping suggest questions to ask - Good models such as Broadbent’s are usually stated in a way that suggests further questions

which can be answered by doing further experiments, and the results of these experiments often lead to the proposal of a new, updated model

*Chapter 2 – Cognitive Neuroscience - Cognitive neuroscience: the study of the physiological basis of cognition - Neurons: building blocks and transmission lines of the nervous system - Fig2.1 physiological processes that occurred in Juan to turn off his alarm clock

o Sound waves changed into electrical waves that are transferred into the brain o Signals that reached the auditory area of the brain caused Juan to hear the alarm o After Juan hears the alarm, the signal is sent to the motor system to muscles in Juan’s

arm and hand so he can turn off the alarm Neurons: the building blocks of the nervous system

- The microstructure of the brain: neurons o 19th century anatomists applied special stains to brain tissue (compared different types

of tissues) o Discovery of the nerve net (continuous, like a highway system in which one street

connects directly to another, but without stop signs or traffic lights) Nerve net: provided a complex pathway for conducting signals uninterrupted

through the network (fig.2.2a) o One reason for describing the microstructure of the brain as a continuously

interconnected network was that the staining techniques and microscopes of the time could not resolve small details, and without these details, the nerve net appeared to be continuous

o Camillo Golgi (1870): developed the staining technique using silver nitrate (fig.2.2b) Individual cells were randomly stained (advantage: can see the complete

structure of the individual cell) o Ramon y Cajal: interested in investigating nerve net, which stained only some of the

cells in a slice of brain tissue 1) used Golgi stain (stained some of the cells in the brain tissue) 2) he decided to study tissue from the brains of newborn animals because the

density of cells in the newborn brain is small compared to the density in the adult brain

He stained 1% of the neurons where he could see that the Golgi-stained cells were individual units

Cajal’s discovery that individual units called neurons were the basic building blocks of the brain was the centerpiece of neuron doctrine (the idea that individual cells transmit signals in the nervous system, and that these cells are not continuous with other cells as proposed by the nerve net theory

He visualized that the role of neurons was to transmit signals o Fig.2.3: cell body = contains mechanisms to keep the cell alive

Dendrites: branch out from the cell body to receive signals from other neurons Axons or nerve fiber: transmits signals to other neurons

o Cajal concludes:

1) there are also neurons that pick up information from the environment (such as the neurons in eyes, skin, and ear receptors = similar to neurons, but it is specialized on picking up info from the environment)

2) Synapse: small gap between the end of the neuron’s axon and the dendrites or cell body

3) Neurons are not connected indiscriminately to other neurons, but form connections only to specific neurons. Usually many neurons are connected together to form neural circuits

Summary: Cajal introduced the concepts of neurons, synapses and neural circuits (the person who made this cellular study of mental life possible)

- The signals that travel in neurons - Determining the exact nature of the transmitted signals depends on the development of

electronic amplifiers that were powerful enough to make the extremely small electrical signals generated by the neuron possible

- Edgar Adrian (1920)– was able to record electrical signals from single sensory neurons o Recorded the action potential from the single neuron o He also found that each action potential travels all the way down the axon without

changing its size o The action potential started at one of an axon, the signal is still the same size when

it reaches the other end o When the signal reach the other end, neurotransmitters are released to transmit

the message across the synaptic gap, that separates the end of the axon from the dendrite or cell body of another neuron (fig.2.4)

o (similar to how the internet transmit electrical signals without describing how the signals are transformed into words and pictures that people can understand)

o People’s experience o He studied the relation between nerve firing and sensory experience by measuring

how the firing of a neuron from a receptor in the skin changed as he applied more pressure to the skin

o He found that shape and size was the same but the rate of nerve firing (action potentials) increased (fig.2.6)

Action potentials recorded from an axon in response to 3 levels of pressure stimulation on the skin; light, medium, strong

Increasing stimulus intensity causes an increase in the rate of nerve firing o Cognition: intensity of stimulus can be represented by the rate of nerve firing

Magnitude of experience such as feeling pressure on the skin or experiencing the brightness of a light

o Amplitude of experience our perception for comparing o Quality of experience different experience associated with each of the senses

- Method (recording from a neuron) (fig 2.5)

o Adrian recorded electrical signals using microelectrodes (small shafts of hollow glass filled with a conductive salt solution that can pick up electrical signals at the electrode tip and conduct these signals back to a recording device

o Recording electrode (positioned near a neuron): connected to the recording device and to another electrode called reference electrode, which is located outside of the tissue

o always measuring the difference in charge between the recording and reference electrodes & is displayed on an oscilloscope (indicates the difference in charge by the vertical position of a small dot that creates a line as it moves across the screen)

o when an electrical signal, called nerve impulse or action potential, is transmitted down, the graph is deflected up and then back down

Localization of Function (fig. 2.7)

- specific functions are served by specific areas of the brain - cerebral cortex: layer of tissue about 3mm thick that covers the brain - localization for perception

o primary receiving areas for senses o temporal lobe: the auditory area where sound stimulates receptors in the ear, the

resulting electrical signals reaches o occipital lobe: primary receiving areas for vision

if damaged: cause blindness o parietal lobe: area for the skin senses (touch, temperature, and pain)

underside of the temporal lobe (smell) small area within the frontal lobe (taste)

o frontal lobe: receives signals from all of the senses and plays an important role in perceptions that involve the coordination of information received through two or more senses

o brain damage: stroke disruption of the blood supply to the brain, usually due to blood clot

o prosopagnosia: an inability to recognize faces caused by suffering damage to a certain area in the temporal lobe on the

lower right side of the brain people who have this condition can recognize a face is a face but cannot

recognize whose face it is (even cannot recognize their own face) the person can still recognize objects based on their voices of mannerism

and have normal memory & general cognitive functioning o brain imaging: been used to demonstrate localization of function in the human

cortex o fusiform face area (FFA): responses to faces in the fusiform gyrus on the

underside of the temporal lobe, corresponds to the area usually damaged in patients with prosopagnosia

o Parahippocampal place area (PPA): activated by pictures representing indoor and outdoor scenes (scenery)

Important for spatial layout o Extrastriate body area (EBA): activated by pictures of bodies and parts of the bodies

(but not by faces) o Modularity: used to refer to localization o Module: an area specialized for a specific function

- Method (brain imaging)

o technique for measuring brain activity in humans allows researchers to create images that show which areas of brain are activated as awake humans carry various cognitive tasks

o position emission tomography (PET) takes advantage of the fact that blood flow increases in areas of the brain that are activated by a cognitive task

to measure blood flow, a low dose of a radioactive tracer is injected into a person’s bloodstream

then the person’s brain is scanned by the PET apparatus, which measures the signal from the tracer at each location in the brain

higher signals indicate higher level of brain activity (fig. 2.8) this method allows researcher to track the activation of brain active through

the blood flow subtraction technique brain activity is measured first in a “control state” before stimulation is

presented, and again while the stimulus is presented the activity is measured as the person manipulates the object the activity due to manipulation is determined by subtracting the control

activity from the stimulation activity (fig. 2.9) o functional magnetic resonance imaging (fMRI)

blood flow can be measured without radioactive tracers takes advantage of the fact that hemoglobin, which carries oxygen in the

blood, contains a ferrous (iron) molecule (has magnetic properties)

if a magnetic field is presented to the brain, the hemoglobin molecules line up like tiny magnets

fMRI determines the relative activity of various areas of the brain by detecting changes in the magnetic response of the hemoglobin

subtraction technique can also be used in fMRI because fMRI doesn’t require radioactive tracers and is more accurate

fMRI main method for determining which areas of the brain are activated by different cognitive functions

- Localization for Language o Paul Broca and Carl Wernicke

Studies of patients whose difficulty in producing and understanding language could be traced to damage in different areas of the brain

Broca’s area: in the frontal lobe Broca’s aphasia: patients has difficulty expressing themselves, but they

have no trouble understanding what other people were saying Wernicke’s area: in the temporal lobe Wernicke’s aphasia: patient’s speech was fluent and grammatically correct

by tended to be incoherent

They make meaningless speech and were unable to understand speech and writing

Example: the apple was eaten by the girl, the boy was pushed by the girl

Patients with broca’s aphasia can understand the first sentence but not the second one because the patient has difficulties processing the words, “was” and “by”

Patient with wernicke’s aphasia will have difficulties with both sentences

o Event-related potential (ERP):recording rapid electrical responses of the human brain

is recorded with small disc electrodes places on a person’s scalp

each electrode picks up signals from groups of neurons that fire together ERP is ideal for investigating a process such as understanding a conversation Rapid responses of the ERP contrasts with the slow response of the brain

imaging techniques such as fMRI, which takes seconds to develop Disadvantage: is it difficult to pinpoint where an ERP is originating in the

brain, but it isn’t as straightforward as the fMRI, which highlights specific structures that are activated

Useful for distinguishing between form and meaning in language, because the ERP consists of a number of waves that occur at different delays after a stimulus is presented linked to different functions

Two aspects that respond to language = N400 and P600 component (N stands for negative, P stands for positive, numbers = time at which the response peaks in milliseconds)

Fig 2.14 o A) The N400 wave of ERP is affected by the meaning of the

word. Becomes larger (red line) when the meaning of a word does not fit the rest of the sentence

o B) The P600 wave of the ERP is affected by grammar. It becomes larger (red line) when a grammatically incorrect form is used

- Specific language functions are localized in specific brain areas, so that localization of function is an important part of language processing

- Language processing is distributed over a large area of the brain - (test yourself section)

Distributed processing in the brain

- Distributed process: specific functions are processed by many different areas in the brain - Faces strongly activate FFA plus other areas as well - Certain area of the brain participate in perception and some other areas also participate in

reactions of the faces o (fig.2.15 evaluation of attractiveness, emotional reactions (inside brain below

cortex), basic face processing (FFA; under brain), awareness of gaze direction, initial processing)

- Fig. 2.16 distribution of activity in the brain while observing a ball roll o Each qualities of the ball activates the brain

Colour (red), movement (to the right), shape (round), depth, location… The importance of the observation extends beyond perceiving a rolling ball

to other cognitive functions such as memory, language, making decisions, and solving problems

Representation in the brain

- Action potentials, specialized areas of the brain, distributed activity in the brain - Representing a tree: feature detectors:

o The mind is a system that creates representations of the world, so we can act within it to achieve our goals

o retina: the layer of neurons that lines the back of the eye o image: created by light reflected by the object that gets into the eye, not the object

itself

o what enters the eye is a representation of the object; something that stands for the object

o the object is based on action potentials, neural impulses in the brain o feature detectors: respond to features that make up objects (fig. 2.17) o David Hubel & Thorsten Wiesel

Monitor the cortex of cats and monkeys & determine which visual stimuli caused each neuron to fire (fig. 2.18)

They found that each neuron fired only to a specific type of stimulation presented in a small area of the retina

Neural code: patterns of neural firing represent environmental stimuli (Fig. 2.19) the types of nerve firing patterns that would be recorded from a

few of the feature detectors that respond to the tree

A) rapid, evenly spaced firing

B) slower, evenly spaced firing

C) irregular firing

D) bursts of firing

E) little or no firing

The overall [pattern of firing of these neurons and the many other neurons that respond to the tree are the neural representation of the tree

- The neural code for faces o Specificity coding: the representation of a specific stimulus, such as a particular

person’s face, by the firing of very specifically tuned neurons that are specialized to respond just to that face (fig. 2.21, 2.22, 2.20)

o grandmother cell (by Jerry Lettvin): is a neuron that responds only to a specific stimulus (stimulus could be a specific image, concept, or the real thing)

limitations of this idea:

there are just too many different face and other objects in the environment to assign specific neurons to each one

although there are neurons that respond only to specific types of stimuli, such as faces, even these neurons respond to a number of faces

o each face is represented by a pattern of firing across a number of neurons o distributed coding: code that indicates a specific face is distributed across a number

of neurons pattern of firing of a number of individual neurons, and distributed

processing refers to the activation of a number of different areas of the brain)

advantage: firing of just a few neurons can signal a large number of stimuli o our ability to identify and recognize the huge number of different objects in our

environment is the end result of distributed cooperation among neurons

- the neural code of memory o neural firing associated with experiencing a perception: caused by stimulation of the

sensory receptors

o neural firing associated with experiencing a memory: caused by firing structures that contain information about what happened in the past

- “Mind reading” by measuring brain activity o Experiment by Svetlana Shikareva & others (page 41) o (Test yourself)

*Chapter 3 – Perception (Pages.48-53, 66-77) - The nature of perception

o Perception: experiences resulting from stimulation of the senses o Crystal’s experience of how a driftwood magically transformed into an umbrella

Perception starts at the receptors: bottom up processing - Bottom up processing: processing beginning with stimulation of the receptors

o physiologically and behaviourally - bottom up processing: physiologically

o sequence of events that occur after light reflected from a tree stimulates the visual receptors in the eye

o stimulation of receptors triggers a series of events in which signals are transmitted from the receptors toward the brain

o neurons in the cortex that respond best to simple shapes like lines or bars with specific orientations are called feature detectors because they respond to simple features (use of oriented bars, fig. 2.18)

- bottom- up processing: behavioural o perception can be created by combinations of individual features has been

purposed by Irving Biederman o his idea, recognition-by-components (RBC) theory (fig3.3):

purposes that we perceive objects by perceiving elementary features called geons

geons: perceptual building blocks that can be combined to create objects From RBC, one characteristic of object perception: we can recognize an

object if we are able to perceive just a few of its geons

We can also perceive objects even if portions of the geons are obscured

o Principle of componential recovery: if we can recover (see) an object’s geons, we can identify the object

If we can’t see an object’s individual geons, we can’t recognize the object o RBC provides an example of bottom-up processing because its basic unit (geon) is

simple and because perceiving simple geometric objects can be related to patterns of stimulation of the retina

Beyond bottom-up processing

- Perception depends on additional information o Top-down processing: processing that begins with a person’s prior knowledge or

expectations is also involved in our ability to recognize objects based on just a few geons

or when large portions of the object are obscured (fig. 3.6)“multiple personalities of a blob” – what we expect to see in

different contexts influences our interpretation of the identity of the “blob” inside the circles

o Feedback signals: signals travel down from higher centers to influence incoming signals

o Physiological point of view: perception of an object is based on signals representing the object plus signals representing other aspects of the environment and feedback signals representing prior knowledge or expectations

- Perceiving size: taking distance into account o Depth, the perceptual system could also be taking into account the size of the

object relative to other objects in the environment o Fig. 3.9

Neurons and knowledge about environment

- Designing a perceiving machine o Program was designed to pick up verticals and horizontals (ceilings, walls, and the

floor) o Program the computer to be able to sense flat surfaces (floors, ceilings, and walls)

Would operate more efficiently if it were programmed to be especially sensitive to features that occur frequently in rooms

“perceiving machine” – the brain - The human “perceiving machine”

o Physical regularities in the environment: horizontals and verticals are common features of the environment, and behavioural experiments have shown some people are more sensitive to these orientation than other orientation that are not as common (the oblique effect)

o There are more neurons that respond to horizontals and verticals through the process of evolution the brain has evolved to respond best situations or stimuli that are commonly found in the environment

o Theory of natural selection: genetically based characteristics that enhance an animal’s ability to survive & reproduce passed down generation

o Through the evolutionary process, the visual system may have been shaped to contain neurons that respond to things that are found frequently in the environment

o Great deal of evidence that learning can shape the response properties of neurons through a process called: experience-dependent plasticity

- Experience- dependent plasticity: o Mechanism through which the structure of the brain is changed by experience o The brain is changed or shaped by its exposure to the environment so it can

perceive the environment more efficiently o Experiments has shown that if an animal is reared in a particular environment,

neurons in the animal’s brain change so they become tuned to respond more strongly to specific aspects of that environment

o Colin Blakemore and Graham Cooper (fig. 3.29) Found that rearing a kitten in an environment consisting only verticals,

reshaped the kitten’s visual cortex so it eventually contained neurons that responded mainly verticals (same if the kitten was place in horizontals = result horizontal)

o Also experimented on humans using fMRI Findings in the FFA that contain many neurons that respond best to faces

o Isabel Gauthier & coworkers (fig.3.31) Determined whether this response to faces might be due to experience

dependent plasticity by measuring the level of activity in the FFA response to faces and to objects called Greebles

Greebles families of computer generated “beings” that all have the same basic configuration but differ in the shapes of their part (like faces)

People who have had little experience in perceiving Greebles the faces causes more activity than the Greebles in the FFA

Gave participants “Greeble recognition” turn them into “Greeble experts”

Results: FFA contains neurons that respond not just to faces but to other complex objects as well depends on experience with the object

Exposure to things that occur regularly in the environment can cause neurons to become adapted to respond best to these regularities

Reaching for a cup: the interaction between perceiving and taking action

- Movement facilitates perception o Movement helps us perceive objects in the environment more accurately o Moving reveals aspects of objects that are not apparent from a single viewpoint o (fig. 3.32 three views of a “horse.” Moving around an object can reveal its true

shape)

- The interaction of perception and action (page 71) o Movement is important because of coordination that is continually occurring

between perceiving stimuli and taking action toward these stimuli o (fig. 3.33 perceive cup, reach for cup, grasp cup)

Involves coordination between perceiving and action that is carried out by two separate streams in the brain

- The physiology of perception and action o Close connection between perceiving objects and interacting with them, but the

details of this link between perception and action have become clearer as a result of physiological research that began in the 1980s

o Two processing stream in the brain: perceiving objects & locating and taking action toward these objects

o Two method brain ablation: the study of effect of removing parts of the brain in animals neuropsychology: the study of the behaviour of people with brain damage

o classic experiment by Leslie Ungerleider and Mortimer Mishkin removing part of a monkey’s brain affected its ability to identify an object

and to determine the object’s location used brain ablation

goal of brain ablation = to determine the function of a particular area of the brain

(first) determine the animal’s capacity (perception) by testing it behaviourally

Used monkeys = similar to humans

(after) goes through ablation to see what function is affected by the removal of that part

Two task: an object discrimination problem and a landmark discrimination problem

Object discrimination problem: a monkey is shown one object and was then presented with a two choice task

o Included the “target” object and another stimulus o If the monkey pushed aside the target object receive

food reward o Monkey with temporal lobe removed had difficulties

Temporal (what pathway)

Landmark discrimination problem: monkey’s task is to remove the food well cover that is closer to the tall cylinder

o Monkey with parietal lobe removed had difficult Parietal lobe (where pathway)

o Neuropsychology: one central procedures dissociations (fig. 3.36) Dissociations – function is absent while another function is present Single dissociation – can be studied in one person Double dissociation – which require or more people

o Dissociation: studied by Milner and Goodale (D.F.’s case) A) D.F’s orientation task B) results for orientation task D.F suffered damage to her temporal lobe from carbon monoxide poisoning D.F. demonstrated a single dissociation, which indicates orientation vision

and action involve different mechanism Milner and Goodale suggested:

visual cortex to the temporal lobe called perception pathway o Corresponds to what pathway

Visual cortex to the parietal lobe called action pathway o Corresponds to where pathway

- Picking up a coffee cup and other behaviours

o Coordinate their activity to create perceptions and behaviours - Mirror neurons:

o Found in the premotor neuron o Neurons that respond both when a monkey observes someone else (usually

experimenter) grasping object o Neurons response to watching and performing the action o Audiovisual mirror neurons:

Respond when a monkey performs a hand action and when it hears the sound associated with this action

*CHAPTER 4: ATTENTION

Attention: the ability to focus on specific stimuli or locations

Selective attention: the focusing of attention on one specific location, object or message

We focus on what is important at a particular time and shift where we are looking from one place,

object or sound source to another

Overt attention: process of shifting attention from one place to another by moving the eyes – this

movement provide observable signals of how attention is changing

Covert attention: occurs when attention is shifted without moving the eyes – seeing something “out

of the corner of the eye”

Divided attention: attending to two or more things at once – can be covert, overt or combination of

both

SELECTIVE ATTENTION:

- We focus on some things to the exclusion of others

Selective Attention as Filtering:

- Early experiments – idea of a „filter‟ that acted on incoming information, keeping some info

out and letting some info in for further processing

o Mainly used auditory stimuli in early selective attention experiments

o Dichotic listening experiment (used by Colin Cherry): in which different messages

are presented to the two ears

o Selective attention experiment: participants pay attention to the message presented to

one ear (the attended message), repeating it out loud as they are hearing it

o And ignore the message presented to the other (the unattended message)

o Procedure of repeating a message out loud is called shadowing – ensures that

participants are focusing their attention on the attended message

o The unattended message also stimulates the auditory receptors though participants

could only tell that there was a message and whether it was a female or male voice –

couldn‟t report the content of the message

o Cherry showed that a listener can attend to just one message; Broadbent created a

model called early selection model to describe how this this selective attention is

achieved

- Early Selection model – proposes that information passes through following stages:

o Sensory memory holds all of the incoming information for a fraction of a second and

transfers all of it to the next stage

Sensory

Memory

Filter Detector To memory

o The filter identifies the attended message based on its physical characteristics -

speaker‟s tone of voice, pitch, speed of talking, and accent – and lets only this

message pass through to the detector in the next stage.

o The detector processes information to determine higher-level characteristics of the

message, such as its meaning. Because only the important, attended information has

been let through the filter, the detector processes all of the information that enters it.

o Short-term memory receives the output of the detector; holds info for 10-15 sec and

transfers it to LTM which can hold info indefinitely.

Messages To memory

- Broadbent‟s model has been called a bottle neck model because the filter restricts info flow

much as the neck of a bottle restricts the flow of liquid; upon pouring liquid the narrow neck

restricts the flow of liquid so the liquid escapes slowly even though there is a large amount in

the bottle.

o He proposed that the filter restricts the large amount of info available to a person so

that only some of this info gets through the detector

o Also, filter lets info through based on specific physical characteristics such as the rate

if speaking, pitch of speaker‟s voice

- Moray did an experiment in which participants heard their names in the unattended ear,

which denies Broadbent‟s theory that filter is supposed to let through only one message

- This cocktail party phenomenon occurs when, in the process of focusing attention on one

message or conversation, a message from another source enters consciousness. This can

occur when a person is focusing attention on a conversation at a party and suddenly hears his

or her name from across the room

- More experiments showed that information presented to the unattended ear is processed

enough to provide the listener with some awareness of its meaning

- Anne Treisman modified Broadbent‟s theory and proposed: (fig 4.5)

o Selection occurs in two stages; replaced Broadbent‟s filter with attenuator

o The attenuator analyzes the incoming message in terms of (1) physical characteristics

(high or low pitched, fast or slow), (2) its language (how the message groups into

syllables or words), (3) its meaning (how sequences of words create meaningful

phrases

→ → →

→ → →

→

→

↑ Attended message

o Attenuation theory of attention is that selection occurs in two stages. In the first stage

attenuator analyzes the incoming message and lets through the attended message –

and also the unattended message, but in a lower (attenuated) strength. Refer to fig 4.5

o Final output of the system is determined in the second stage when the message is

analyzed by the dictionary unit which contains stored words, each of which has a

threshold for being activated.

o Threshold is the smallest signal strength that can barely be detected, thus a word with

low threshold might be detected even if it is presented slowly

o Words that are common and important (such as listener‟s name) have low thresholds

and even a weak signal activates these words; compared to uncommon words which

need stronger signals

- Late Selection models of attention propose that most of the incoming information is

processed to the level of meaning before the message to be processed is selected

o E.g. Donald Mackay experiment: participants listened to ambiguous sentences, such

as “they were throwing stones at the bank”, that could be taken more than one way

(i.e. river bank or financial institution)

o These sentences were presented to the attended ear, while biasing words were

presented in the unattended ear (e.g. as participants were shadowing the sentence

above, either the word “river” or “money” were presented in the unattended ear)

o After hearing a number of ambiguous sentences, participants were presented with

pairs of sentences such as:

They threw stones toward the side of the river yesterday

They threw stones at the savings and loan association yesterday

o When they indicated which of these two sentences was closest in meaning to one of

the sentences they had heard previously, MacKay found that the meaning of the

biasing word affected participants‟ choice (e.g. if the biasing word was „money‟,

participants were more likely to pick the second sentence)

Cognitive Resources, Cognitive Load and Task-irrelevant Stimuli:

- Cognitive resources refers to the idea that a person has a certain cognitive capacity, which

can be used to carrying various tasks

- Cognitive load is the amount of a person‟s cognitive resources needed to carry out a

particular cognitive task; some tasks, especially easy, well-practiced ones, have low cognitive

loads

- Low load tasks use up only a small amount of the person‟s cognitive resources

- High load tasks are difficult and not well practiced; thus use more of a person‟s cognitive

resources

- One thing that has been studied about cognitive resources and cognitive load is the relation

between:

1) The amount of a person‟s cognitive resources that are used by a primary task or

stimulus and

2) How this affects the person‟s ability to avoid attending to other, task-irrelevant

stimuli

- Nilli Lavie has proposed that the amount of cognitive resources that remain as a person is

carrying out a primary task determines how well the person can avoid attending to task-

irrelevant stimuli – refer fig. 4.7

o Low-load tasks that use few cognitive resources may leave resources available for

processing task-irrelevant stimuli, whereas high load tasks that use all of a person‟s

cognitive resource don‟t leave any resources to process task-irrelevant stimuli

- Flanker compatibility task is a procedure in which participants are instructed to respond to

a target stimulus that is flanked, or surrounded, by distractor stimuli that they are supposed to

ignore. The degree to which the distractor interferes with responding to the target is taken as

an indication of whether the distractor stimuli are being processed – refer figure 4.9

o Compatible flanker: a stimulus in the display for a flanker compatibility task that is

associated with a response that is the same as or compatible with the response that the

participant is supposed to make to a target stimulus

o Incompatible flanker: a stimulus in the display for a flanker compatibility task that is

associated with a response that is different from the response that the participant is

supposed to make to a target stimulus

- Stroop effect is a task in which a person is instructed to respond to one aspect of a stimulus,

such as the color of ink that a word is printed in, and ignore another aspect, such as what the

word spells. The stroop effect refers to the fact that people find this task difficult when the

ink color differs from what the word spells

DIVIDED ATTENTION:

- Divided attention refers to the distribution of attention among two or more tasks; the ability

to divide attention depends on a number of factors, including practice and difficulty of task

Divided Attention Can be Achieved with Practice: Automatic Processing

- Experiments on divided attention by Schneider and Shiffrin require participants to carry out

two tasks simultaneously (1) holding information about target stimuli in memory and (2)

paying attention to a series of „distractor‟ stimuli and determining if one of the target stimuli

is present among these distractor stimuli (refer to figure 4.12)

- Participant was shown a memory set, consisting of one to four characters called target

stimuli.

- The memory set was followed by rapid presentation of 20 test frames, each of which

contained distractors.

- On half of the trials, one of the frames contained a target stimulus from the memory set

- A new memory set was presented on each trial, so the targets changed from trial to trial,

followed by new test frames

- The targets and distractors were always from different categories, so if the targets were

numbers, the distractors were always letters

- Consistent mapping condition – even though the targets change from trial to trial, the

participants always knew that the target would be numbers and the distractors would be

letters

- Participants reported that after about 600 trials, the task had become automatic

- Practice made it possible for participants to divide their attention to deal with all of the target

and test items simultaneously

- Automatic processing is a type of processing that occurs (1) without intention (happens

automatically without person intending to do it) and (2) at a cost of only some of a person‟s

cognitive resources

Divided Attention when Tasks are Harder: Controlled Processing

- Harder experiment: the targets in the memory set and distractors are both letters; targets and

distractors are changed on each trial

- Varied mapping condition – rules keep changing from trial to trial; participants never

achieved automatic processing in the experiment since it is much more difficult

- Varied mapping condition processing is called Conditioned processing – participants had to

pay close attention at all times and had to search for the target among the distractors in a

focused and controlled way

Distractions while Driving

- Hands-free is not the solution since the problem isn‟t driving with one hand

- The problem is driving with fewer cognitive resources available to focus attention on driving

- Also, there is a difference between talking on a cell phone and talking to a passenger; person

on the phone isn‟t aware of the road and traffic conditions whereas a passenger is aware of

the traffic situation and would pause the conversation or warn the driver of upcoming hazards

etc.

- Distraction of attention associated with talking on a cell phone or using GPS can degrade

driving performance

ATTENTION AND VISUAL PERCEPTION

- The idea that attention is so important that, without it, we may fail to perceive things that are

clearly visible in our field of view

Inattentional Blindness

- Definition - Not noticing something even though it is in clear view, usually caused by failure

to pay attention to the object or the place where object is located

- Fig 4.17 – creates a situation in which a person‟s attention is focused on one task and then

determining whether the person perceived an easily visible nearby stimulus

- Daniel Simons and Christopher Chabris experiment

o Created a 75 sec film that showed two teams of three players each

o The team that was dressed in white was passing a basketball around, and the other

team dressed in black was not handling the ball

o Observers were told to count the number of passes, a task that focused their attention

on the team in white

o After about 45 sec, an event that took 5 sec occurred – one of these events was person

dressed as a gorilla waking through the scene

o Nearly half of the observers failed to report having seen the event

o Thus, when observers are attending to one sequence of events, they can fail to notice

another event, even when it is right in front of them

Change Detection

- Lack of attention can affect perception

- Researchers have conducted experiments in which instead of presenting a task that distracted

attention from a test stimulus, they presented one picture and asked observers to indicate

whether they saw any difference between the two pictures – participants detected difference

after several trials

- This difficulty in detecting changes in scenes is called change blindness. The changes are

often easy to see once attention is directed to them (i.e. a cue), but are usually undetected in

the absence of appropriate attention

- More examples on pg. 97

- Exogenous attention – automatic attraction of attention by a sudden visual or auditory

stimulus

- Endogenous attention – occurs when a person consciously decides to scan the environment to

find a specific stimulus or monitor what is happening; can also occur for auditory stimuli

OVERT ATTENTION: ATTENDING BY MOVING OUR EYES

- Overt attention is shifting of attention by moving the eyes

- In inattentional blindness and change blindness experiments, people missed objects or

changes in environment that they were not paying attention to, but when people were told to

look in a scene, they could detect the changes that had previously missed

Eye movements, attention and perception

- Eye tracker: a device for measuring where people look (fixate) in a scene and how they move

their eyes from one fixation point to another

- Fixation: a pausing of the eyes on places of interest while observing a scene

- Saccadic eye movements: eye movements from one fixation point to another

- People make typically three fixations per second when viewing an unfamiliar scene

- Two factors that determine how people shift their attention by moving their eyes: bottom-up

and top-down determinants

o Bottom-up:

Attention can be influenced by stimulus salience – the physical properties of

the stimulus such as color, contrast or movement

Capturing attention by stimulus salience is a bottom-up process because it

depends solely on the pattern of light and dark, color and contrast in a

stimulus (e.g. find people wearing yellow hats)

Meaning of the object attracts attention too.

o Top-down:

Associated with scene schema – an observer‟s knowledge about what is

contained in typical scenes

The fact that people look longer at things that seem out of place in a scene

means that attention is being affected by their knowledge of what is usually

found in the scene

Research shows that when a person is carrying out a task, the demands of the

task override factors such as stimulus saliency

Fig. 4.27 – eye movements in making a peanut butter sandwich

Person‟s eye movement was determined primarily by task – i.e. participants

did not look at objects or areas that were irrelevant to the task

The eye movement usually preceded a motor action by a fraction of second, as

when the person first fixated the peanut butter jar and then reached over to

pick it up

This is an example of just-in-time strategy – eye movements occur just before

we need the information they will provide

Note: although eye movements often indicate where a person is directing

attention, it is possible to be looking directly at something without paying

attention to it

COVERT ATTENTION: DIRECTING ATTENTION WITHOUT EYE MOVEMENTS

- Attention that is not associated with eye movements is called covert attention

- Has been studied with a procedure called precueing in which the participant is presented with

a „cue‟ that indicates where a stimulus is most likely to appear

- Precueing has been used to study location-based attention – how attention is directed to a

specific location or place and object-based attention – attention that is directed to a specific

object

Location-based attention:

- Fig 4.28: Participants in Posner and coworkers experiment kept their eyes stationary

throughout the experiment, always looking at the +

- They first saw an arrow cue indicating in which side of the target a stimulus was likely to

appear

- In the figure, cue indicates that they should focus their attention to the right (without moving

their eyes)

- The participants‟ task was to press a key as rapidly as possible when a target square was

presented off to the side

- 4.28(a) is a valid trial because the square appears on the side indicated by the cue arrow

- 4.28(b) is an invalid trial because the cue arrow indicated that the observer should attend to

left, but the target was presented on the right

- Results showed participants reacted more rapidly on valid trials than invalid trials

- Thus, info processing is more effective at the place where attention is directed

Object-based attention:

- When attention is directed to one place on an object, the enhancing effect of this attention

spreads throughout the object

- Fig 4.29 Participants kept their eyes on +, one end of rectangle was briefly highlighted. This

was the cue signal that indicated where a target, a dark square would probably appear

- The cue indicated that the target is likely to appear in the upper part of the rectangle

- The participants‟ task was to press a button when the target appeared anywhere in the display

- Reaction times were faster when the target appeared where the cue signal predicted it would

appear

- The most important result is that participants responded faster within the same rectangular

object at location B, which is in the same object as A

- Thus, same-object advantage occurs when the enhancing effect of attention spreads

throughout an object, so that attention to one place on an object results in a facilitation of

processing at other places on the object

FEATURE INTEGRATION THEORY:

- Def: an approach to object perception developed by Anne Treisman that proposes that object

perception occurs in a sequence of stages in which features are first analyzed and then

combined to result in perception of an object

- First step in processing an image of an object is the preattentive stage – in which objects are

analyzed into separate features (Fig 4.31 a rolling red ball would be analyzed into the features

of color (red), shape (round) and movement (to the right))

- Since each of these features is processed in a separate area of the brain, they exist

independently of one another at this stage of processing

- Experiment in (Fig. 4.33) - illusory conjunctions: can occur even if the stimuli differ greatly

in shape and size (E.g. a small blue circle and large green square may be seen as a large blue

square and a small green circle)

- Illusionary conjunctions occur because at the beginning of the perceptual process each

feature exists independently of the others – they are „free floating‟ and can be incorrectly

combined if there is more than one object

- Second stage is called focused attention stage – the features are combined in this stage and

once they are combined we perceive the object

- The feature analysis approach involves mostly bottom-up processing because knowledge is

usually not involved

THE PHYSIOLOGY OF ATTENTION

- Research has studied the physiological mechanisms of attention and two important results are

(1) attention enhances neural responding and (2) attentional processing is distributed across a

large number of areas in the brain

Covert Attention Enhances Neural Responding

- Neural responding is affected by shifting attention covertly - without eye movements

- The reason is that the eye movements that accompany overt attention cause a change in the

image of the retina, which can cause a neural response

- Just to be sure that any neural responses are caused not by changes in the image on the retina

but by the changes in attention, research use a covert attention procedure in which the eyes

remain stationary

- Refer to Fig 4.36 for a covert attention experiment

Attentional Processing is Distributed Across the Cortex

- Gordon Shulman and coworkers showed that attention to a particular direction of motion

increases activity in number of brain structures

- Using fmri, they measured participants‟ brain activity while they performed a task in which they

paid attention to a specific direction of motion

- Participants either saw (1) a cue that alerted them to pay attention to a particular direction of

motion or

(2) a cue indicating that they should just passively observe the display on the screen (Fig. 4.37)

- Following the cue, participants saw random motion which was created by a field of dots that

were moving in random directions

- After about a second, some of the dots started moving in the cued direction of motion, a

condition called coherent motion because a number of dots were moving in the same direction

- If the participants had seen the direction cue, their task was to press a key when they saw the

coherent motion

- If they had seen the other cue, they were to continue passively observing the display.

- Brain activity was measured during and after the cue was presented but before the coherent

motion

- Three different types of attentional processing:

(1) Alerting – is achieving a high sensitivity to incoming stimuli

(2) Orienting – is focusing attention where visual targets may appear; this occurs in both overt

and covert attention

(3) Executive control – occurs for tasks that involve conflict, such as the Stroop task or flanker

compatibility task

- Executive functions that involve resolving conflicts between responses cause by different stimuli

are served by areas in the frontal lobe which is also the site of high-level thinking

*Chapter 5 – Short term & working memory The importance of memory in our lives

- Memory is the processes involved in retaining, retrieving and using information about stimuli, images, events, ideas and skills after the original info. Is no longer present

- We can use memory as a time machine to go back just a moment – to the worlds - “mental time travel” afforded by memory can place you back in a situation – feel like reliving it - Memory list- how important memory is in their day to day lives

Studying memory

- One tactic cognitive psychologists have used is to create models like Donald Broadbent’s filter model (fig.4.3) that purpose a series of processing stages to explain how people can selectively attend to one message out of many

- One of the advantage: help organize what we know about an area + what we need to ask - Modal Model of memory (Richard Atkinson + Richard Shiffrin)

o Included many of the features of memory models that were being purposed in the 1960s

o Stages of the model called: structural features o There are three major structural features:

Sensory memory: is an initial stage that holds all incoming information for seconds or fractions of second

Short term memory: (STM) holds 5-7 items for about 15-30 seconds Long term memory: (LTM) can hold a large amount of information for years or

even decades - Atkinson and Shiffrin described the memory system as including control processes

o Active processes that can be controlled by the person and may differ from one task to another

o rehearsal – repeating a stimulus over and over as you might repeat a telephone number in order to hold it in your mind after looking it up in the phone book or internet

o control processes: 1) strategies you might use to help make a stimulus more memorable 2) Strategies of attention that help you focus on info. That is particularly

important or interesting o Encoding – process of storing the number in long-term memory o Retrieval – process of remembering info. that is stored in long term memory o Before we can be aware of this stored info., it must be moved back into STM

Sensory Memory

Sensory memory – the retention, for brief periods of time, of the effects of sensory stimulation - Example: the trail left by a moving sparkler and the experience of seeing a film - The lighted trail is a creation of your mind, which retains a perception of the sparkler’s light for a

fraction of a second - Persistence of vision - retention of the perception of light in your mind - ex. during film in a darkened movie theater

o a single film frame is positioned in front of the projector lens, and when the projector’s shutter opens, the image on the film frame flashes onto the screen

o the shutter then closes so the film can move to the next frame without causing a blurred image, and during that time, the screen is dark

o when the next frame has arrived in front of the lens, the shutter reopens, flashing the next image onto the screen

o the process is repeated rapidly, 24 times per second, so 24 still images are flashed on the screen every second, with each image separated by a brief period of darkness

o person doesn’t see the dark intervals between the images because of the persistence of vision fills in the darkness by retaining the image of the previous frame

o early films were called “flickers” Sperling’s experiment: Measuring the capacity and duration of the sensory store

- persistence of vision effect that adds a trail to our perception of moving sparklers and fills in the dark spaces between frames in a film has been known since the early days of psychology

- George Sperling: wondered how much info. people can take in from briefly presented stimuli o Experiment (fig. 5.5): he flashed an array of letters (50 milliseconds) and asked his

participants to report as many of the letters as possible o Whole report method- participants were asked to report as many letters as possible

from the whole matrix An average of 4.5 out of the 12 letters

o He concluded that because the exposure was brief, participants saw only an average of 4.5 of the 12 letters however he thought of another possibility:

Participants saw most of the letters immediately after they were presented, but their perception field faded rapidly as they were reporting the letters, so by the time they has reported 4-5 letters, they could no longer see the matrix or remember what had been there

Partial report method – to determine which of these two possibilities is correct

this technique: he flashed the matrix for 50ms, but immediately after it was flashed, he sounded one of the following cues tones, to indicate which row of letters the participants were to report (fig. 5.5b)

the tone was presented after the letters were turned off, the participant’s attention was directed not to the actual letters, which were no longer present, but to whatever trace remained in the participant’s mind after the letters were turned off

the cue allowed the participants to direct their attention to the certain row

average: 3.3 or 4 letters in that row

conclusion: immediately after the display was presented, participants saw an average of 82% if the letters in the whole display, but were not able to report all of these letters because they rapidly faded as the initial letters were being reported

delayed partial report method – the presentation of cue tones was delayed for a fraction of a second after the letters were extinguished

results: when the cue tones were delayed for 1 second after the flash, participants were able to report only slightly more than 1 letter in a row, the equivalent of about 4 letters for all three rows – same number of letters they reported using the whole report method

(fig. 5.6) – results of sperling’s 1960 partial report experiments. The decrease in performance is due to the rapid delay of iconic memory (sensory memory in the modal model)

o Conclusion from the results: short lived sensory memory registers all or most of the information that hits our visual receptors, but that this info. decays within less than a second

o Iconic memory or visual icon - brief sensory memory for visual stimuli – and corresponds to the sensory memory stage of Atkinson and Shiffrin’s model

o other research using auditory stimuli = shown that sounds also persist in the mind o echoic memory – persistence of sound – lasts for a few seconds after presentations of

the original stimulus o sensory memory only retains the information for seconds or fractions of a second

importance of this memory

collecting info. to be processed

holding the info. briefly while initial processing is going on

filling in the blanks when stimulation is intermittent - importance of Sperling’s experiment/discovery

o reveals the capacity of sensory memory (large) and its duration (brief) Short term memory

- involved in storing small amounts of information for a brief period of time - recall test - participants are presented with stimuli and they after a delay, are asked to

remember as many of the stimuli is possible - memory performance can be measured as a percentage of the stimuli that are remembered - participant’s responses can be analyzed to determine if there is a pattern to the way items are

recalled - recall – involved when a person is asked to recollect life events, such as graduating from high

school, or to recall facts they have learned o measuring recall contrasts with measuring recognition – which people are asked to pick

an item they have previously seen or heard from a number of other items that they have not seen or heard

What is the duration of STM?

- John Brown, Lloyd Peterson, Margarent Peterson o Experiment: remembering three letters (page. 124)

- Decay- participants forgot the letters because of this o Their memory trace decayed because of the passage of time after hearing the letters

- G. Keppel and Benton Underwood o Suggested that the dropoff in memory was due not to decay of the memory trace

(Peterson and Peterson purposed), but proactive inference (PI) o Proactive inference (pi) - interference that occurs when information that was learned

previously interferes with learning new information

Keppel and underwood proposed that proactive interference is what caused the decrease in memory observed in the later trials of Peterson and Peterson

- The outcome of this constant interference is that the effective duration of STM, when rehearsal is prevented is about 15-20 seconds

What is the capacity of STM?

- Digit span- the number of digits a person can remember - the average capacity of STM is about 5 to 9 items – about the length of a phone number - George Miller – famous paper titled The magical number seven, plus or minus 2 - Other researches: STM only remembers 4 items - Steven Luck & Edward Vogel

o Measured the capacity of STM by flashing two arrays of coloured squares separated by a brief delay

o The participant’s task was to indicate whether the second array was the same as or different from the first array

o On trials in which the second array was different, the colour of one square was changed o Result (fig. 5.8a,b): performance was almost perfect when there were 1 to 3 squares in

the arrays, but that performance began decreasing when there were 4 or more squares o Concluded: participants were able to retain about 4 items in their short term memory

- Chunking - to describe the fact that small units (like words) sentences, paragraphs, or stories o in terms of meaning increases our ability to hold information in STM o we can recall a sequence of 5 to 8 unrelated words, but arranging the words to form a

meaningful sentence so that the words become more strongly associated with one another increased the memory span to 20 words or more

- Chunk – collection of elements that are strongly associated with one another but are weakly associated with elements in other chucks

o Experiment: remembering letters - K.Anders Ericsson – demonstrated an effect of chucking by showing how a college student with

average memory ability was able to achieve amazing feats of memory o Participant S.F. asked to repeat strings of random digits that were read to him o Although S.F. had a typical memory span of 7 digits, after extensive training (230 one hr

session), he was able to repeat sequences of up to 79 digits without error o S.F. used the chucking method – recode the digits into larger units that formed

meaningful sequences - William Chase & Herbert Simon

o Chess players arrangements of chess pieces taken from actual games for 5 seconds o The chess players were then asked to reproduce the positions they had seen o (fig. 5.9a) most players got 16 out of 24 correctly on their first try and 4 out of 24 for

beginners o Master only four trials to reproduce all the positions exactly o All the players saw the pieces as meaningful pattern and groups chucking it

- Chucking enables the limited capacity STM system deal with the large amount of information involved in many of the tasks we perform everyday

How is information coded in STM?

- Coding – the way information is represented - Physiological approach to coding – determining how a stimulus is represented by the firing of

neurons

- Mental approach to coding - by asking how a stimulus or an experience is represented in the mind

- Types of coding: auditory = sound of the person’s voice, visual = image of a person, semantic = meaning of what the person is saying

- Auditory coding: representing items in STM based on their sound o R. Conrad experiment: participants saw a number of target letters briefly on a screen

and were told to write down the letters in the order they were presented Found that when participants made errors , they were most likely to misidentify

the target letter as another letter that sounded like the target Concluded: STM is auditory rather than visual

- Visual coding: representing items visually as would occur when remembering the details of a floor plan or the layout of streets on a map

o Sergio Della Sala participants were presented with a task (recalling visual patterns) Task: pattern are difficult to code verbally, so completing the pattern depends

on visual memory (fig. 5.10 test patterns) He found that participants were able to complete patterns consisting of an

average of 9 shaded squares before making mistakes How can they remember 9? combination of individual squares into

subpatterns

Example of chucking, which could increase the number of squares remembered

- Semantic coding - representing items in terms of their meaning o Delos Wickens (fig. 5.11)

On each trial, participants were presented with words related to either (a) fruits, or (b) professions

Participants in each group listened to three words, counted backward for 15 seconds, and then attempted to recall the three words

They did 4 trials with different words presented for each trial o Basic idea: to create proactive interference – decrease in memory that occur to prior to

learning, by presenting words in a series of trials from the same category o Results (fig. 5.12): average percent = 86, but performance dropped after 2,3,4, trials

Blue data points indicate the presence of proactive interference caused by repeated presentation of the names of fruits

o Evidence that this interference can be attributed to the meanings of the word, is provided by the results for the professions group

o Because there was another category, proactive interference has decreased o Released from proactive interference – proactive interference is reduced, which results

in an increase in performance the release from proactive interference tell us to realize from PI that occurs in

the Wickens experiment, depends on the words’ categories placing words into categories involves the meaning of the words = semantic

coding Working Memory

- the modal model stimulated a great deal of research on STM - experiment: Reading text and remembering number - Baddeley: he found that participants were able to read while simultaneously remembering the

numbers

o He concluded that the STM must be dynamic and must also consist of a number of components that can function separately

- Graham Hitch o The STM component of memory is called working memory o Working memory –limited capacity system for temporary storage and manipulation of

information for complex tasks such as comprehension, learning and reasoning

- Differences between working memory and STM

STM Working Memory

storing information for a brief period of time (remembering phone number)

Manipulation of information that occurs during complex cognition (remembering numbers while reading a paragraph)

single component number of components

- Working memory accomplishes the manipulation of information through the action of three

components: - Phonological loop Consists of 2 components:

o phonological store – has a limited capacity and holds information for only a few seconds o articulatory rehearsal process – responsible for rehearsal that can keep items in the

phonological store from decaying o phonological loop holds verbal and auditory information

- visuospatial sketch pad holds visual and spatial information o forming images in your mind, solving puzzles

- central executive major work of working memory occurs o central executive pulls information from LTM and coordinates the activity of the

phonological loop and visuospatial sketch pad by focusing on specific parts of a task and switching attention from one part to another

o can be looked at as a traffic cop o Coordinating and combining visual and verbal info. (fig. 5.15)

- Phonological similarity effect - the confusion of letters or words that sound similar o Misinterpreting similar sounds (such as F and S)

- Word length effect - when memory for lists of words is better for short words than for long wordsou

- Articulatory suppression – repetition of an irrelevant sound results o Reduces memory because speaking interferes with rehearsal o The … the…. The…. o This occurs when remembering the second list becomes harder because repeating “the..

the.. the..” overloads the phonological loop The Visuospatial Sketch Pad

- Visuospatial sketchpad handles visual and spatial information and is therefore involved in the process of visual imaginary

- Visual imaginary – the creation of visual images in the mind in the absence of a physical visual stimulus

- Roger Shepard and J. Metzler – comparing objects

o Measured the reaction time to decide whether pairs of object shown were the same or different

o They obtained the relationship for the objects are the same o They found that the reaction time was greater when there was greater differences in

orientation o Shepard and Metzler inferred that participants were solving the problem by rotating an

image of one of the objects in their mind o Mental rotation- example of the operation of the visuospatial sketch pad because it

involves visual rotation through space - When phonological loop is disrupted by interference, so is the visuospatial sketch pad

o Lee Brooks – how interference can affect the operation of the visuospatial sketch pad o Holding a spatial stimulus in the mind

Results (page. 136): most people thought the pointing task is more difficult Holding the image of the letter and pointing are both visuospatial task, so the

visuospatial sketch pad becomes overloaded The Central Executive

- Working memory “working” o It is the control center of the working memory system o Mission to not story information, but to coordinate how information is used by the

phonological loop and visuospatial sketch pad o Baddeley- describes the central executive as being an attention controller

It determines how attention is focused on a specific task, how it is divided between two tasks, and how it is switched between tasks

- Central executive studied by assessing the behaviour of patients with brain damage - Frontal lobe patients is perseveration

o Perseveration - repeatedly performing the same behaviour even if it is not achieving the desired goal

a person with frontal lobe damage might be responding correctly on each trial, as long as the rule stays the same

however when the rule is switched, the person continues following the old rule, even when given feedback that his or her responding is now incorrect

the perseveration represents a breakdown in the central executive’s ability to control attention

The Episodic Buffer

- episodic buffer – (Baddeley) can store information (thereby providing extra capacity) and is connected to LTM (thereby making interchange between working memory and LTM possible)

o fig. 5.22* o if the exact functioning of the episodic buffer seems a little vague, it is because it is a

“work in progress” o “the concept of an episodic buffer is still at a very early stage of development”

- Episodic buffer: represents a way of increasing storage capacity and communicating with LTM Working Memory and the Brain

- Major methods o 1) analysis of behaviour after brain damage o 2) recording from single neurons in animals o 3) recording electrical signals from the human brain

- Delay and waiting The Effect of Damage of the Prefrontal Cortex

- Delayed – response task – required a monkey to hold information in working memory during a delay period (early research method)

o The monkey sees food reward in one of two food wells o Both wells are then covered, a screen is lowered, and then there is a delay before the

screen is raised again o When the screen is raised, the monkey must remember which well has the food and

uncover the food well to obtain the reward o Monkey’s can be trained to accomplish task

- Supports the idea of how the prefrontal cortex is important for holding information for brief periods of time

Prefrontal Neurons that Hold Information

- Neurons continued to fire even during the delay - Particular location - Research has also found neurons that are involved with working memory in other areas of the

brain, including the primary visual cortex, which is the first area of the brain to receive visual signals

Brain Activation in Humans

- Used techniques such as PET and fMRI to measure brain activity in humans - Edward Vogel – experiment on the allocation of attention by measuring a component of the

event-related potential (ERP) in humans, recorded during working memory - Participants were divided in the high memory capacity group or the low memory capacity group - The participants’ task was to respond to the test display by indicating whether the orientations

of the red rectangles in the cued side of the test display was the same as or different from the orientations of the red rectangles on the cued side of the memory display

- Results: fig. 5.28 when just red rectangles were presented was similar for the high capacity and low capacity participants

o However, adding blue rectangles had little effect on the response of the high capacity group but caused an increase in the response of the low capacity group

o The fact that adding the two blue rectangles had little effect on the response of the high-capacity group means that these participants were very efficient at ignoring the distracters, so the irrelevant blue stimuli did not take up any space in working memory, because allocating attention is a function of the central executive, this means that the central executive was functioning well for these participants

o The fact that adding the two blue rectangles caused a large increase in the response of the low capacity group means that these participants were not able to ignore the irrelevant blue stimuli and the blue rectangles were therefore tasking up space in working memory

- Conclusion: some people’s central executives are better at allocating attention than others

- Reading span – designed to measure both the storage and processing functions of the working memory

o By measuring the max. number of sentences that a person can read while simultaneously holding the last word in each sentence in memory

*Chapter 6 – Long-Term Memory: Structure

- Korsakoff’s syndrome: a condition caused by a prolonged deficiency of vitamin B1, usually as a result of chronic alcoholism

o This leads to destruction of areas in frontal and temporal loves, which causes severe permanent impairments in memory

o - Anterograde Amnesia: the loss of the ability to assimilate or retain new knowledge - Retrograde amnesia: the loss of memory for events that have happened in the past

Distinguishing Between Long-Term Memory and Short-Term Memory

- Long-term memory (LTM) is the systems that is responsible for storing information for long periods of time

Long-term and Short-term Processes

- Everything from 5 minutes ago to a memory from 10 years earlier is part-of long-term memory

- In LTM, recent memories tend to be more detailed and much of this detail and often the specific memories themselves fade with the passage of time

- LIM provides both an archive that we can refer to when we want to remember events from the past, and a wealth of background information that we are constantly consulting as we use working memory to make contact with that is happening at a particular moment

- The interplay between what is happening in the present and information from the past, which we described in the interaction between Tony and Cindy (Figure 6.2, pg. 150), is based on the distinction between STM/WM and LTM

- EXPERIMENT: Distinction between STM and LTM – SERIAL POSITION (pg. 151) Serial Position Curve

- Serial Position Curve: In a memory experiment in which participants are asked to recall a list of words, a plot of the percentage of participants remembering each word against the position of that word in the list

- The curve indicates that memory is better for words at the beginning and at the end of a list than the middle

- Primacy effect: superior memory for stimuli presented at the beginning of a sequence o Possible explanation: participants had time to rehearse these words and transfer

to LTM Participants begin rehearing the first word right after it is presented; no

other words have been presented which receives 1—percent of the person’s attention

When second word is presented, attention becomes spread over two words, and so on; as additional words are presented, less rehearsal is possible for later words

- EXPERIMENT: The idea that primacy effect occurs because participants have more time to rehearse earlier words was tested by Dewey Rundus

o Derived a serial position curve by presented a list of 20 words at rate of 1 word every 5 seconds and then asking participants to write down words they could remember

o Figure 6.4 (pg.152) shoes same primacy and recency effect as Murdoch’s o ADDED FURTER TWIST: asked participants to study the list as it was being

presented by repeating words out loud during the 5-second intervals between words

o Results: Words presented early in list were rehearsed more, and they were more likely to be remembered later.

o This result supports the idea that the primacy effect is related to the longer rehearsal time available for the earlier words on the list

- Recency effect: superior memory for stimuli presented at the end of a sequence o Possible explanation: most recently presented words are still in STM

- EXPERIMENT: Murray Glanzer and Anita Cunitz tested this idea o first deriving a serial position curve in the usual way o Then in another experiment, they measured the curve after having their

participants count backward for 30 seconds right after hearing the last word of the list

Counting prevented rehearsal and allowed time for information to be lost from STM

o Results: the delay caused by counting eliminated the recency effect o Conclusion: the recency effect is due to storage of recently presented items in

STM

Coding in Long-Term Memory - We can also distinguish between STM and LTM by comparing the way information is

coded by the two systems - Although all three types of coding can occur in LTM (auditory, visual semantic), semantic

coding is the predominant type of coding in LTM - Semantic coding illustrated by kinds of errors that people make in tasks that involve

LTM o Example: misremembering the word tress as bush (indicate meaning of the word

is what was register in LTM) - EXPERIMENT: Jacqueline Sachs demonstrated the importance of meaning in LTM

o Had participants listen to a tape recording of a passage and then measured their recognition memory to determine whether they remembered the exact wording of sentences in the passage or the general meaning of the passage

o Participants remembered the sentence’s meaning and not its exact wording o The finding that specific wording is forgotten by the general meaning can be remember

for a long time has been confirmed in many experiments

- Recognition memory: the identification of a stimulus that was encountered earlier

Locating Short- and Long-Term Memory in the Brain Neuropsychological studies

- Clive Wearing: the musician who lost his memory as a result of viral encephalitis o Has functioning STM but unable to form new LTMs

- H.M.: neurosurgeons removed his hippocampus on both sides of the brain in an attempt to eliminate epileptic seizures

o has a functioning STM but absent LTM o Operation eliminated the seizures but also eliminated his ability to form new

LTM - Table 6.1 (p. 155): evidence supports the idea that STM and LTM are caused by different

mechanism, which can act independently Brain imaging

- EXPERIMENT: DeborahTalmi and coworkers measured the fMRI response to tasks involving STM and LTM

o First presented a list of words to participants, as is done to determine a serial position curve

o Instead of asking participants to recall the words, they presented a single “probe” word

Probe was either (1) a word from near the beginning of the list (2) a word from near the end of the list (3) a new word that hasn’t been presented earlier

o Participants task was to indicate whether the word has been presented before o Brain activity was measured with fMRI after the probe was presented and as

they were preparing to respond o Results: probe words that were from the beginning of the list activated areas of

the brain associated with both long-term and short-term memory Probe words at the end of the list only activated areas of the brain

associated with short-term memory Types of Long-Term memory

- Explicit (conscious) memory, contents can be described or reported, consists of : o Episodic memory: memory for personal experiences

Ex. Remembering talking to a friend yesterday o Semantic memory: stored knowledge and memory for facts

Ex. Remembering the facts learned in class - Implicit (unconscious) memory are memories that are used without awareness:

o Priming: a change in a response to a stimulus caused by the previous presentation of the same or a similar stimulus

Ex. Reading recently view words is easier vs. words rarely encountered o Procedural memory: memory for doing things

Ex. Ability to type notes o Classical conditioning: when pairing an initially neural stimulus with another

stimulus results in the neutral stimulus taking on new properties

Ex. Red SUV smashed into your car. Now when you see a Red SUV or even red cars you feel anxious

Episodic and Semantic Memory (Explicit) Distinguishing between Episodic and Semantic Memory

- Distinguishing episodic and semantic memory based on types of information remembered

- Endel Tulving suggested that episodic and semantic memory can be also distinguished based on the type of experience associated with each

- Defining property of the experience of episodic memory is that is involves mental time travel: the experience of traveling back in time to reconnect with events that happening in the past

- Experience of mental time travel/episodic memory is described as self-knowing or remembering

o Putting oneself back in a situation through mental time travel does not guarantee that the memory is accurate

- The experience of semantic memory involves accessing knowledge about the world that does not have to be tied to remember a personal experience

o Things like facts, vocabulary, numbers and concepts - When we experience semantic memory, we are accessing things we are familiar with

and know about o Ex. I know many facts about Pacific Ocean but can’t remember exactly when I

learned these things - Tulving describes he experience of semantic memory as knowing

Connections between Episodic and Semantic Memories Episodic Memories Can Be Lost, Leaving Only Semantic Memories

- Example: In 6th grade you learn that the legislative branch of the U.S. government consists of the Senate and the House of Representatives

o A few weeks later if you remember what was going on in class as you were learning these facts, you are having and episodic memory, and if you remember the facts about the House and Senate, you having a semantic memory

o Years later you still know the difference between the Senate and the House of Representative (semantic memory still present), but it is unlikely that you remember what was happening on the specific day you were sitting in class in the 6th grade learning about U.S. government (episodic memory has been lost)

o Thus: illustrates the knowledge that makes up semantic memories is initially attained through ha personal experience that could be the basis of an episodic memory, but memory for this experience often fades, leaving only semantic memory

- Another example: High school graduation

Semantic Memory Can Be Enhanced If Associated With Episodic Memory - Semantic memories that have personal significance are easier to remember than

semantic memories that are not personally significant o Ex. Knowledge about the facts associated with your high school graduation has

personal significance for you - People have better recall for names of public figures whom they associate with personal

experiences o More likely to recall the name of a popular singer in a test if you had attended

one of their concerts than if you had just read about the singer in magazines Semantic Memory Can Influence Our Experience by Influencing Attention

- Example: Steven and Troy watching a football game o Troy remembers the details of the play but it doesn’t stand out for Steven o Troy remembers because his semantic memory, which contains a large amount

of knowledge about football caused him to direct his attention to what various players were doing as the play unfolded

o Troy’s detailed semantic memory about the various types of plays in football helped direct his attention, and he formed memories about specific plays

Priming, Procedural Memory, and Conditioning (Implicit)

- Implicit memory occurs when some previous experience influences our performance on a task, even though we do not consciously remember the previous experience

- Tulving describes implicit memory as nonknowing Priming

- Priming: occurs when the presentation of one stimulus (the priming stimulus) changes the response to a subsequent test stimulus (the test stimulus) either

o positively (postivie priming, which causes an increase ins peed or accuracy of the response of the text stimulus) or

o negatively (negative priming, which causes a decrease in the speed or accuracy of response to the test stimulus)

- Repetition priming: occurs when the test stimulus is the same as or resembles the priming stimulus

o Ex. Seeing the word bird may cause you to respond more quickly to another presentation of the word bird than a word you have not seen, even though you may not remember seeing bird earlier

- Conceptual priming: occurs when the enhancement caused by the priming stimulus is based on the meaning of the stimulus

o Ex. Presentation of the word furniture might cause you to respond faster to a later presentation of the word chair

- Avoiding explicit remember in a priming experiment (p. 161) - Proof that priming involves implicit memory is provided by neuropsychology

experiments - EXPERIMENT: Peter Graf and coworkers tested three groups of participants:

(1) : 8 amnesia patients with Korsakoff’s syndrome and 2 patients with another form of amnesia

(2): patients without amnesia who were under treatment for alcoholism (3) patients without amnesia who has no history of alcoholism

o Presented lists of words to their participants and asked them to rate each word on a scale of 1 to 5 based on how much they liked each word (to prevent words to memory)

o After rating words, participants were tested in one of two ways (1) a test of explicit memory, in which they were asked to recall the

words they had seen (2) a test of implicit memory, in which they were presented with three-

letter fragments and were asked to add a few letters to create the first word that came into their mind

o Results of recall experiment amnesia patients has poor recall compared to the two control groups This poor recall confirms the poor explicit memory associated with their

amnesia o Results of implicit memory test:

The percentage of primed words that were created in the word completion test demonstrates that the amnesia patient performed just as well as the controls

This shows that priming can occur even when there is little explicit memory for the words

- Implicit memory is not simply a laboratory phenomenon, but also occurs in everyday experience

o Ex. Exposure to advertisements that praise the virtues of a product or perhaps just present the product’s name

- Propaganda effect: participants are more likely to rate statements they have read or heard before as being true, simply because they have been exposed to them before

o The effect involves implicit memory because it can operate even when people are not aware that they have heard or seen a statement before

Procedural Memory

- Procedural memory: also called skill memory because it is memory for doing things that usually require action

- The implicit nature of procedural memory has been demonstrated in amnesia patients who can master a sill without remembering any of the practice that led to this mastery

- Mirror Drawing: trace a picture of a star by looking at its reflection o H.M. did this task. After a few days of practice, H.M. became good at mirror

drawing but each time he did it, he thought he was practicing it for the first time o H.M.’s ability to trace the star in the mirror, even though he couldn’t remember

having done it before, illustrates procedural memory - People who can form new long-term memories can still learn new skills The fact that

people with amnesia can retain skills from the past and learn new ones has led to an

approach to rehabilitant patients with amnesia by teaching them tasks, such as sorting mail, that they can become expert at, even though they can’t remember their training

Classical Conditioning

- Classical Conditioning: occurs when the following two stimuli are paired: o (1) a neutral stimulus that initially does not result in a response, and o (2) a conditioning stimulus that does result in a response

- Example: presenting a tone to a person followed by a puff or air to the ye that cuases the person to blink

o Initially does not cause an eye blink but after a number of pairing with the puff of air, the tone alone causes eye blink