Transcript lecture 01

Memory 3265
• Course website address
• http://www.yorku.ca/npark/memory_f_14
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
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). 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%
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
– 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; 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
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