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Introduction to Cognitive Psychology
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What is Cognitive Psychology?
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Cognitive psychology is the study of mental processes
What is Cognitive Psychology?
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Cognitive Psychology versusBehaviorism Behavioral Psych: how S maps onto R Cognitive Psych: what happens in the mind Both can use formulas to map S onto R The difference is level of complexity
Environment MindS
R
What is Cognitive Psychology?
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Cognitive Psychology versusNeurobiology Neurobiology: how does the brain do it? Cognitive Psych: how does the mind do it? Both can use neurons to describe mind The difference is behavior (the big picture)
What is Cognitive Psychology?
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Metaphor: mind = Windows Behaviorists:
“What happens when I press Alt-Tab? Cool! It switched to my last open application!!” But how does that work?
Neurobiologists: “Check this out, the harddrive and the RAM are both
connected to the motherboard!” But what does that mean?
Cognitive Psychologists: “Pressing Alt-Tab switches me between applications, and I
know that Windows uses STM… Let’s propose a model of Windows where it stores which apps are open in STM, and when a user hits Alt-Tab, it switches between open apps.”
What is Cognitive Psychology?
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Cognitive Psychology versusArtificial Intelligence (AI) AI: what’s the best way to do this? Cognitive Psych: how do humans do this? Both try to model some form of mind The difference is fidelity Brain is optimal: If AI truly wants to find
optimality they should study Cognitive Psychology.
Why study Cognitive Psychology
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Understanding the mindEducationMedicineTherapyArtificial IntelligenceTool/Interface DesignGaming/EntertainmentEtc.
What is involved in Cognition
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The book lists: Perception, Attention, Memory, Problem-Solving,
Language, Reasoning, & Decision-makingThis is not a comprehensive list of mental
processesThese processes are not independent of one
another E.g. attention may be part of perception;
language may be part of memory and decision-making, etc.
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Complexity of Cognition
Figure 1.1 (p. 3) - Complexity of CognitionSarah is walking toward her friend, who is waving in the distance. She is aware of her friend, but has little awareness of the stranger who is passing on her right, even though he is much closer.
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What we are aware of…
The complexities of cognition are usually hidden from our consciousness.
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The Magic of Cognition
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In our lives we are likely to NEVER encounter the same retinal input twice!
EVER!
We will learn about categorization and invariant representation
The Magic of Cognition
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The Stroop effect We have automatic reading routines It is hard to stop well-practiced routines from
executing This is the difference between experts and novices
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Figure 1.5 (p 8) - Hemholtz’s unconcious inferenceThe display in (a) looks like (b) a gray rectangle in front of a light triangle; but it could be (c) a gray rectangle and a six-sided figure that are lined up appropriately.
Complexity of Perception; Expectations
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The Herring illusionThe diagonal lines give the impression of moving forward- the lines look like optic streaks (streaks of neural activation in the retina)When moving forward, straight lines (like doorways) start looking like curves on the retina.
Complexity of Perception; Expectations
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The Magic of Cognition
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These types of phenomena give us a hint as to how cognition works
E.g. Do you process all of the information that falls on your retina? It may be that we have a perfect representation of the
world It may be that we make gross estimations based on prior
experience DEMO
Complexity of Cognition
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The “understand-the-brain” jigsaw puzzle is particularly daunting… To get a sense of the difficulty, imagine a jigsaw puzzle with several thousand pieces. Many of the pieces can be interpreted multiple ways, as if each had an image on both sides but only one of them is the right one. All the pieces are poorly shaped so you can’t be certain if two pieces fit together or not. Many of them will not be used in the ultimate solution, but you don’t know which ones or how many. Every month new pieces arrive in the mail. Some of these new pieces replace older ones, as if the puzzlemaker was saying, “I know you’ve been working with these old puzzle pieces for a few years, but they turned out to be wrong. Sorry. Use these new ones instead until future notice.” Unfortunately, you have no idea what the end result will look like; worse, you may have some ideas, but they are wrong.
- Jeff Hawkins, On Intelligence
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Methodology
How CogPsych is studied
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Donders reaction time experiment
Figure 1.3 (p. 6)A modern version of Donders’ (1868) reaction time experiment. (a) the simple reaction-time task; and (b) the choice reaction-time task. For the simple time reaction text, the participant pushes the J key when the light goes on. For the choice reaction time test the participant pushes the J key if the left light goes on, and the K key if the right light goes on. The purpose of the Donders experiment was to determine the time it took to decide which key to press for the choice reaction time test.
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Figure 1.4 (p. 7)Sequence of events between presentation of the stimulus and the behavioral response, in Donders’ experiment. The dashed line indicates that Donders measured reaction time, the time between presentation of the light and the participant’s response. (a) simple reaction-time task; (b) choice reaction-time task. www.gyanbigyan.com
How CogPsych is studied
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Behavioral and physiological
Correction:
Figure 1.9 (p. 15)Updated sequence of events between stimulus and response, taking into account the physio-logical response. A, B, & C show relationships that can be measured. The mental response must be inferred from these relationships.
Stimulus
Physical/Mental Response
Response
E.g. Think back to the “mind=Windows” metaphor.
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Figure 1.10 (p. 16)Design of Davachi et al. (2003) experiment. There were two parts to this experiment. The first part, learning, was followed one day later by a memory experiment. Note that the participants’ brain activity was measured during the learning task using a technique called functional magnetic resonance imaging.
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Figure 1.11 (p. 17)Results for the behavioral part of the Davachi et al. (2003) experiment. This graph indicates the relationship between how the participants related to the stimulus (place or read) during learning and their performance in the memory test. This corresponds to Relationship A in Figure 1.9.
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Figure 1.12 (p. 18)The results of the physiological part of the Davachi et al. experiment. Left: The relationship between how the participants reacted to the stimulus during learning (place or read) and the physiological response (Relationship B). Right: The relationship between the physiological response and the behavioral response (whether the person recognized or forgot the word) (Relationship C).
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Information Processing Approach
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Mind as a processor of information Input -> Mental Processes -> Output
To understand it, build it
Task MindI
O
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Think Critically
Think Critically
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Beware cognitive myths We only use 10% of our brain Group brainstorming Left vs right hemisphere
Left is an accountant, right is a hippie Phrenology
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Think Critically
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Beware vacuous Statements E.g. (p. 4) “the Stroop effect shows that some stimuli
can affect our behavior by forcing themselves on our consciousness, even if we are actively trying to ignore them.”
Think Critically
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Beware old theories E.g. Chomsky’s Poverty of Stimulus argument (p.
10) has been rebuked recently; Perfors, Tenenbaum, & Regier (2006) have shown that with the right approach it is possible to retrieve grammar rules from the data available to children
Think Critically
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Correlation does not imply causation 100% of people who eat pickles die Therefore, eating pickles is bad for you
Think Critically
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“Davachi … [states that] memory is better if the perirhinal cortex is activated when the word is being learned” (p. 18)
Does this mean that Perirhinal cortex is involved in memory? Everything is involved in memory
Is it involved in associative learning? Not necessarily. It could be activated during the “place” task
for any number of reasons• Maybe Ss found it amusing to place words, and the
perirhinal cortex is actually the amusement center; maybe being amused correlates with better memory
Think Critically
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Cognition is far from being solved Ask questions Use your intuition Do thought experiments Use multiple sources of information Think for yourselves
How would you design the mind?
On the brighter side…
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This is a young field, but we understand a lot about cognition already
At this point we are already able to predict Learning curves for procedural and declarative
memories How forgetting works (interference and decay) How some memories can prime other memories How cognitive mechanisms interact And much much more
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