Transcript lecture 01

Memory 3265
• Course website address
• http://www.yorku.ca/npark/memory_f_16
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
Introduction and History of
Memory Research
• History
– however, people did write about factors affecting
memory performance
attentiveness 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
Introduction and History of
Memory Research
• 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 information
developed the method of loci. In this method a
person places items to be memorized in particular
locations well known to the memorizer
Introduction and History of
Memory Research
• 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
– Investigated the factors associated with forgetting
– Memory performance as a function of delay
between learning and test
Introduction and History of
Memory Research
• History
– experimental procedure of Ebbinghaus
Materials. Used nonsense syllables (CVC) to try
and study acquisition and memory for brand-new
stimuli
Participant. Ebbinghaus
Procedure. 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)
Introduction and History of
Memory Research
• History
– experimental procedure of Ebbinghaus
Procedure (cont’d). After a delay Ebbinghaus
relearned the list.
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%
Introduction and History of
Memory Research
• History
– experimental procedure of Ebbinghaus
Results. Ebbinghaus produced his famous
forgetting curve. There is a precipitous drop in
retention shortly after a list was acquired
Ebbinghaus’ forgetting curve
120
100
80
60
Retention
40
20
0
immed
1 hour 9 hours
100
hours
1000
hours
Introduction
• History
– the tradition of Ebbinghaus
highly controlled experiments
simple stimuli
quantifiable dependent measures
– reaction to its restrictiveness
Gestalt psychologists, Bartlett, and cognitivists
Introduction
• 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 memory
 Secondary memory – now called long-term memory
Introduction
• 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
Introduction
• Other traditions
– ecological validity
– neuropsychology
• Ecological validity
– argues that the Ebbinghaus tradition is
concerned with unimportant problems with little
applicability to real world problems
Introduction
• Ecological validity (cont’d)
– this approach, spearheaded by Neisser (1978,
1982) is controversial
– and there are strong critics of this approach (e.g.,
Crowder)
Introduction
• 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 (early 1800s)
– 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
Introduction
• 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 sensitivity
 Mouth not paralyzed; he could understand speech
 Autopsy revealed damage to left inferior part of frontal lobe
 on the basis of a brain-behaviour case study he claimed that
language is localized to the inferior part of the left frontal
lobe
Introduction
• 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
Introduction
• 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)
Introduction
• 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 aphasia
Broca’s aphasia--speech is nonfluent; ie, short
phrases, poor melodic content, limited
grammatical form
Wernicke’s aphasia-- speech is fluent, but
comprehension is impaired
Lichtheim’s Neuropsychological model of language
Function
Word concept elaboration
3
Motor word
representations
(Broca)
Speech motor
output
Auditory word centre
(Wernicke)
Auditory input
Criticisms 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 makers
– 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
3. Did not carefully and systematically observe the
patients on which theoretical ideas were based
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 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
Cognitive Neuropsychology
• 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
Cognitive Neuropsychology
• 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
Cognitive Neuropsychology
• 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: 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
Introduction: Memory
• 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 piece
how do you use a hammer
Introduction: Memory
• 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
Introduction: Memory
Methodology
• 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
Introduction: Memory
Methodology
• Incidental versus intentional memory
• Explicit memory
– conscious recollection of previous experience
e.g., tell me your telephone number
e.g., try to recall when you first decided to take
this course
– explicit memory can be intentional or
unintentional
e.g., remembering an argument you had with your
friend is explicit, but may be unintentional
Introduction: Memory
Methodology
• 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
Introduction: Memory
Methodology
• Episodic versus semantic memory
– episodic memory is memory for events or
episodes;
– 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
Introduction: Memory
Methodology
• Independent variables
– factor that influence performance of some
dependent measure
– in memory research it is a factor that affects
memory performance
Introduction: Memory
Methodology
• Types of independent variables
– organismic: relatively permanent characteristics
of an individual that affect memory performance
e.g., age, intelligence, health
– antecedent variables: sleep, drugs, time of day
Introduction: Memory
Methodology
• 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
Introduction: Memory
Methodology
• Types of dependent variables
– accuracy
number of items recalled, recognized
types of errors made
scoring criterion: strict…(need to operationalize)
What do you do about guessing?
– speed
– order in which items were recalled
Introduction: Memory
Methodology
• 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
Introduction: Memory
Methodology
• 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 tasks
• Autobiographical memory
– memory of old TV shows
– famous faces
Non-traditional memory tasks
• 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
Non-traditional memory tasks
• Warrington and Weiskrantz (1970)
– tested amnesics and controls on explicit and
implicit memory tasks
subjects 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
Non-traditional memory tasks
• Conclusion
– amnesics may have selective damage to that
part of the memory system that mediates explicit
recollection of stored information