Memory 3265 Course website address

Memory 3265Memory 3265

• Course website address• http://www.yorku.ca/npark/memory_f_15

Introduction and History of Memory Research


• History– Ebbinghaus (1885) is credited with being the first

person to scientifically study memory– prior to Ebbinghaus relatively little was written

about about memory



• History– however, people did write about factors affecting

memory performanceattentiveness and rehearsal aid memory

– Aristotle (4th Century BC)proposed laws of associationism. Most important

is the law of contiguity-- two events or experiences occurring closely in time will come to be associated with each other



• History– Romans (e.g., Cicero) and others were

concerned with using mnemonics to assist memory

– mnemonics generally remember something new by pairing it with already known informationdeveloped the method of loci. In this method a

person places items to be memorized in particular locations well known to the memorizer



• History– Ebbinghaus (1885) published Memory: A

contribution to Experimental Psychology– first experimental study of memory; inspired by

Fechner’s work on the psychophysical study of sensation



• History– experimental procedure of Ebbinghaus

Materials. Used nonsense syllables (CVC) to try and study acquisition and memory for brand-new stimuli

Participant. EbbinghausProcedure. Presented nonsense syllables one at a

time at a fixed rate of presentation. Studied list until he could recall entire list in serial order without error (method of complete mastery)




Procedure (cont’d). Ebbinghaus was concerned with the rate of forgetting as a function of the time interval between initial learning and his attempt to recall the list. If he made one or more errors, Ebbinghaus restudied list until he could recite the list perfectly. The dependent variable was the savings score, ie, the time or trials saved in learning list again. Example, initially took 1500 seconds to learn list; took 600 seconds to relearn list; savings = 900/1500 = 60%




Results. Ebbinghaus produced his famous forgetting curve. There is a precipitous drop in retention shortly after a list was acquired

Ebbinghaus’ forgetting curveEbbinghaus’ forgetting curve

0

20

40

60

80

100

120

immed 1 hour 9 hours 100hours

1000hours

Retention

IntroductionIntroduction

• History– the tradition of Ebbinghaus

highly controlled experimentssimple stimuliquantifiable dependent measures

– reaction to its restrictivenessGestalt psychologists, Bartlett, and cognitivists


• History– Cognitive tradition (William James)

In his classic text, principles of psychology, James distinguished between different types of memory

Habits were 1 type of memory that mediated skills such as walking, writing, and singing

James believed these resulted from a concatenation of reflex mechanisms and pathways, which could combine to produce complex behaviors

Two other forms of memory according to James were:Primary memory – now called short-term working memorySecondary memory – now called long-term memory


• History– Cognitive tradition (William James)

James did not explicitly distinguish between habit and memory

Bergson (1911) proposed that representation of the past has two distinct types of memories – habits and memories

As we shall see, the distinctions proposed by James and Bergson continue to be made


• Other traditions– ecological validity– neuropsychology

• Ecological validity– argues that the Ebbinghaus tradition is

concerned with unimportant problems with little applicability to real world problems


• Ecological validity (cont’d)– this approach, spearheaded by Neisser (1978,

1982) is controversial– and there are strong critics of this approach (e.g.,

Crowder)


• Other traditions (cont’d) Neuropsychology– Neuropsychology: study of disorders of perception,

memory, language, thought, emotion, and action in neurological patients

– Gall proposed theory of cortical localization in which individual cognitive functions are mediated by specific brain regions

– No real evidence for this idea because he examined bumps on skull, which he related to cognitive functions (e.g., pride, vanity, language, and speech)– now called phrenology


• Other traditions (cont’d) Neuropsychology– Broca 1861

51 year old man; lost power to speak (“Tan” was one of the only speech sounds he could make)

Paralyzed on right side with a loss of sensitivityMouth not paralyzed; he could understand speechAutopsy revealed damage to left inferior part of frontal lobeon the basis of a brain-behaviour case study he claimed that

language is localized to the inferior part of the left frontal lobe


• Broca (cont’d)– two important parts of claim

1. Language can be dissociated from other cognitive functions

2. Language function can be localized to a particular brain region


• Carl Wernicke (1894)– Reported case of a patient who could produce

speech, but could not understand speech– Damage to left temporal cortex suggested that

this was site for speech comprehension– this approach to understanding cognitive function

led to the rise of the diagram makers (1860 - 1905)


• Logic of diagram makers– identify distinct syndromes, then attempt to

theoretically link the different syndromes– for example, they identified what they believed

were several distinct types of aphasiaBroca’s aphasia--speech is nonfluent; ie, short

phrases, poor melodic content, limited grammatical form

Wernicke’s aphasia-- speech is fluent, but comprehension is impaired

Auditory word centre(Wernicke)

Auditory input

3

Word concept elaboration

Motor wordrepresentations(Broca)

Speech motoroutput

Lichtheim’s Neuropsychological model of languageFunction

Criticisms of diagram makersCriticisms of diagram makers

• Work of diagram makers has a contemporary flavour and is now appealing to 20th century eyes– Work was attacked for following reasons

1. Postulated that the functions they hypothesized could be precisely localized; evidence do not support this claim

2. Psychological concepts were inadequate; e.g., aphasia was a word-based deficit; evidence suggests that syntax is an important component of the deficit

Criticisms of diagram makersCriticisms of diagram makers

– Work was attacked for following reasons1. Postulated that the functions they hypothesized

could be precisely localized; evidence do not support this claim

2. Psychological concepts were inadequate; e.g., aphasia was a word-based deficit; evidence suggests that syntax is an important component of the deficit

3. Did not carefully and systematically observe the patients on which theoretical ideas were based

Group study approach (1940-1970)

Group study approach (1940-1970)

• Rejected the single-case approach to neuropsychology in favour of the group study approach

• clinical observations became an insufficient basis for theoretical speculation

Cognitive NeuropsychologyCognitive Neuropsychology

• Use information processing models to describe cognitive function; these models are very similar to Lichtheim– note: you can conceptually ‘lesion’ information

processing models

• returned to the use of the case study– however, an experimental approach was used– attempt to use case studies to discriminate between

different models of normal function


• Memory findings by early neuropsychologists– early investigators studied anterograde amnesia

– impaired ability to recall newly learned information

– Retrograde amnesia – loss of memories acquired prior to onset of brain trauma


• Ribot (1882)– Reviewed a large number of cases of retrograde amnesia

following brain damage and head trauma– Memories acquired remotely prior to insult were better

retained compared to memories acquired more recently before insult

– This result is called Ribot’s law or the law of regression– Concluded that memories require time to be organized

and consolidated


• Alzheimer (1906)– Reported the case of a patient with dementia

now known as Alzheimer’s disease (AD)– Showed that 2 important symptoms of AD were:

anterograde amnesia and retrograde amnesia (graded; i.e., remote memory better retained than more recent memory)

Introduction: MemoryIntroduction: Memory

• What sorts of functions are subserved by memory?– Who am I?

If you have no memory of the events that you have experienced (autobiographical memory), then it would be difficult to answer this question

– What do I know?Semantic knowledge about the world


• What sorts of functions are subserved by memory?– Memory for actions

procedural memory; memory is expressed by performance rather than by recollection or verbal description

how do you tie your shoelace?How do you play a musical piecehow do you use a hammer


• What sorts of functions are subserved by memory?– How do I learn?– Why do I forget? Is it functional?

Introduction: Memory Methodology


• Distinctions– Learning refers to the the acquisition of new skills

and information– Memory refers to the retention of what has been

learned over time



• The memory process is composed of three main phases:– encoding or registration: transformation of

information presented to a person into a form that can be retained

– retention: storage of information– retrieval: recollection or remembering of stored

information



• Incidental versus intentional memory• Explicit memory

– conscious recollection of previous experiencee.g., tell me your telephone numbere.g., try to recall when you first decided to take this

course

– explicit memory can be intentional or unintentionale.g., remembering an argument you had with your

friend is explicit, but may be unintentional



• Measuring explicit memory– recall (free or cued)– recognition

• Implicit memory– indirect memory test; conscious recollection not

involved– e.g., mere exposure effect; word stem completion



• Episodic versus semantic memory– episodic memory is memory for events or

episodes; it is stored in terms of its autobiographical reference to already stored information

– semantic memory is the memory necessary for language; it is a mental thesaurus, organized knowledge a person possesses about words, and other verbal symbols and their meaning



• Independent variables– factor that influence performance of some

dependent measure– in memory research it is a factor that affects

memory performance



• Types of independent variables– organismic: relatively permanent characteristics

of an individual that affect memory performancee.g., age, intelligence, health

– antecedent variables: sleep, drugs, time of day



• Types of independent variables (cont’d)– task variables:

instructions (e.g., intentional vs incidental)presentation conditions (e.g., rate of presentation)stimulus variables (e.g., picture, word, type of

word)context in which task occurs



• Types of dependent variables– accuracy

number of items recalled, recognizedtypes of errors madescoring criterion: strict…(need to operationalize)What do you do about guessing?

– speed– order in which items were recalled



• Some standard memory tasks– serial learning: recall items from a list in the exact

order in which they were presented– free recall: recall as many items from a list in any

order– cued recall: present cue-target pairs at study; at

test present cue and have participant recall target



• Some standard memory tasks (cont’d)– Recognition test

multiple-choice test. Participant selects which of 2 or more alternative choices is correct

true-false test (yes/no test)

Non-traditional memory tasksNon-traditional memory tasks

• Autobiographical memory– memory of old TV shows– famous faces


• Implicit memory has become increasingly popular – amnesics remember information when tested

using implicit memory procedures; however, amnesics are unable to remember this information when they are tested using explicit memory procedures


• Warrington and Weiskrantz (1970)– tested amnesics and controls on explicit and implicit

memory taskssubjects were presented a list of words to study;

amnesics were much inferior to controls in their explicit recall and recogniton of the studied words

also tested memory on two implicit memory tasks (word fragment identification and word stem completion e.g., cha----); on these two implicit memory tasks amnesics performed as well as controls


• Conclusion– amnesics may have selective damage to that

part of the memory system that mediates explicit recollection of stored information

Documents

Memory 3265 Course website address