Introduction Human Memory

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IntroductionHuman Memory
13/02/2006, Annette Hohenberger
Baddeley, Alan (1999) Essentials of Human
Memory. Hove Psychology Press. Chapter 1 What
is memory Chapter 4 Learning
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Memory and Time
Future expectation, divination Present
perception, conception (knowledge) Past
Memory (Aristotle, ca. 350 b.c., On memory and
reminiscence, http//psychclassics.yorku.ca/Aristo
tle/memory.htm)
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Memory and reminiscence IAristotle

• Only animals that perceive time and that can
  distinguish a 'former' and a 'latter' remember.
• Memory always involves a 'presentation' and
  therefore belongs to the primary faculty of
  sense-perception or to the faculty of conception.
• The act of perception 'imprints' upon the soul an
  impression of the percept, like a physical
  impression with a seal.
• Do we remember the 'impressed affection' or 'the
  objective thing' from which it was derived?--gt
  both
• '...the mnemonic presentation within us is
  something which by itself is merely an object of
  contemplation, while, in-relation to somthing
  else, it is also a presentaion of that other
  thing.'

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Memory and reminiscence IIAristotle

• Memory ?Recollection Animals have memory but no
  (conscious) recollection.
• Remembering does not imply recollection, but
  recollection always memory (but false memory!)
• 'Recollection is the reinstatement in
  consciousness of something which was there before
  but had disappeared...'
• Recollection is an inference, the result of an
  investigation. Only beings capable of thinking
  for themselves ('faculty of deliberation') can
  remember.
• A memory which cannot be accessed immediately may
  be recollected after some time, starting from a
  'mnemonic locus' and passing through other
  mnemonic loci until the wanted memory is found.

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Memory and reminiscence IIIAristotle

• Some strange ideas...
• Recollection is a searching for an 'image' in a
  corporeal substrate.
• Recollection 'sets up a process in a material
  part, (...) in which resides the affection.'
  Around this part which is the organ of
  sense-perception, there is 'moisture' and this
  moisture is set in motion.
• Recollection instigates 'mnemonic movements which
  have to keep true to a course if they are to find
  the image the person tries to remember.
• Children and old people have bad memories because
  they have a lot of movement going on within them.
  Old people are in a process of decay children in
  one of growth.

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Memory and reminiscence IVAristotle

• Some even stranger ideas...
• 'Those whose upper parts are abnormally large, as
  is the case with dwarfs, have abnormally weak
  memory, as compared with their opposites, because
  of the great weight which they have resting upon
  the organ of perception, and because their
  mnemonic movements are, from the very first, not
  able to keep true to a course...'

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What couldn't we do if we had no memory?
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What is memory for?

• knowledge store
• Learning
• Planning and control of action
• computation
• language (processing, acquisition)
• identity (individual and cultural)

--gt integration of information from various
sensory channels into a coherent view of the
environment --gt building up knowledge about the
world --gt memory is needed for any aspect of
cognition and action
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Further questions about memory
-
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Memory and the environment

• Memory is only functional/advantageous if the
  organism and the environment have certain
  characteristics
• The organism and the environment have to persist
  in space and time (life time!)
• The environment is structured and predictable
  --gt determinism vs. Indeterminism
• Neither fully predictable nor fully
  unpredictable but in a medium range
• Neither maximally nor minimally entropic
• The environment offers resources necessary for
  the organism. Which resources?
• --gt embeddedness, systemic account of organism
  and environment

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Memory and the environment
BUT there are organisms in our environment for
which all these characteristics are true but
which do not have memory at all or which have
very limited memory --gt Memory is a
cognitive characteristic --gt teleological,
functional explanation is not satisfactory --gt
psychophysical basis of memory
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Aplysia Aplysia californica, lumpfish (mollusc)
is capable ofhabituation when it is siphon gets
stimulated, the siphon and the gills are
withdrawn. After repeated stimulation, this
reaction ceases.Sensitization unpleasant
stimulus to the tail enhances the withdrawal
response when the siphon is stimulated.classical
conditioning UCS strong stimulus to the
tailUCR withdrawal of siphon and gillsCS
light touch of siphon (normally does not lead to
withdrawal of siphon and gills)CR withdrawal of
siphon and gills UCS --gt UCR CS ---gt
CRmechanism association of synaptic
connections between nerve cells Bailey, C.H.
and Kandel, E.R. (1995) Molecular and structural
mechanisms underlying long-term memory. In M.
Gazzaniga (Ed.), The cognitive neurosciences,
19-36. Cmbridge, MA MIT Press.
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Synaptic connections
Donald Hebb (1949)--gt Hebb' synapse Hebb, Donald
(1949) Organization of behavior. New York
Wiley. 'Nervous cells that fire together wire
together' Nervous cells build up synaptic
connections and increase the strength between
the synapses when they are frequently active
simultaneously. What happens with nervous cells
that do not wire with any others?
--gt atrophy, pruning
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Subcomponents of the memory processWhen memory
fails...

• Storing trace laid down but fades rapidly
• Retrieval trace present but unaccessible
• Registering no memory trace laid down
• Problem differentiating between these
  possibilities

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What kinds of memories are there?

• Memory is probably not unitary
• -immediate sensory store
• -short term memory/working memory
• -long term memory
• Implicit vs explicit memory
• semantic/declarative vs procedural memory
• what vs. how
• Memory for different cognitive domains
• faces, numbers, language (names),
• Memory in different sensory/motor modalities
• visual, auditory, tactile, motor,

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Taxonomy of memory(Tulving 1972)
Types of memory working long-term (shor
t-term) explicit implicit episodi
c semantic procedural perceptual (event)
(fact) representional Tulving, Endel
(1972). Episodic and semantic memory.
Organization of memory. In E. Tulving and W.
Donaldson. New York, Academic Press.
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The Atkinson and Shiffrin model (1968)
inson, R.C. And Shiffrin, R.M. (1968) Human
memory A proposed system and its control
processes. In K.W. Spence (Ed.), The psychology
of learning and motivation Advances in reesearch
and theory (pp. 89-195). New York Academic
Press.ss.
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Sensory memories
Iconic Memory (vision) Capacity
Essentially that of the visual system (Sperling,
1963)) Duration About 0.5 to 1.0 second
Processing None additional beyond raw
perceptual processing Sperling, G. (1963) A
model for visual memory tasks. Human Factors, 5,
19-31. Echoic Memory (hearing
Capacity ???? Duration About 4 to 5
seconds Processing None additional beyond
raw perceptual processing --gt Benjamin's
experiment
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Short-Term-Memory
Information that is attended to arrives in
another temporary store called short-term or
working memory. Capacity About 7 plus or
minus 2 "chunks" of information (Miller, 1956)
Duration About 18 to 20 seconds (Peterson
Peterson, 1959) Processing To hold
information in STM, it is often encoded
verbally, although other strategies may also be
used such as visualization. To hold Information
in STM, it needs to be rehearsed. Miller,
George A. (1956) The magical number seven, plus
or minus two. Some limits on our capacity for
processing information. Psychological Review, 63,
81-97. Peterson, L.R. And Peterson, M.J. (1959)
Short-term retention of individual verbal items.
Journal of Experimental Psychology, 58, 193-198.
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Long-Term-Memory
Here are some properties of LTM Capacity
Virtually unlimited Duration Up to a
lifetime Processing Information is
organized according to meaning and is
associatively linked Capacity is unlimited
in the sense that nobody seems to run out of the
capacity to store new information, even if they
live beyond 100 year
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Hermann Ebbinghaus (1850-1909)
Learning and Memory
Ebbinghaus was the first to study memory
systematically in experiments (on himself) How
did he go about studying memory? Ebbinghaus,
Hermann (1885) Über das Gedächtnis.
Untersuchungen zur experimentellen Psychologie.
Leipzig.
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3 Methods of Ebbinghaus
Recall Free recall -- attempt to recall items
of a list in any order - immediate -
delayed Serial recall -- attempt to recall the
list items in the order studied.
Recollection Given a large list of nonsense
syllables try to recognize which of them had
been on the list studied. Saving Rememorize
the list (usually used after a long retention
interval, when neither recall nor recognition
produce much evidence of prior learning).
Compare the number of repetitions required
to learn the list the first time to the number
required the second time.

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Free Recall
List of nonsense CVC-syllables WUX CAZ BIJ ZOL LE
F SOF GAN FUP VIB TEM Recall after different
periods of time immediately, 20 min, 1 h, 9 h,
1,2, 6 days How much of the material is
retained/forgotten?

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R e - t / S where R is memory retention, S is
relative strength of memory and t is time. --gt
exponential decay

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Serial position curve Effects Primacy and
RecencyEbbinghaus was the first to discover the
serial position curve -- the relation between the
serial position of an item (its place in the
list) and the ability to recall it. Items near
the beginning of the list are easier to recall
than those in the middle (the primacy effect).
Those near the end of the list are also earier to
recall than those in the middle (the recency
effect.) These two effects together yield a curve
that is roughly U - shaped.
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Role of sensory modality in immediate recall
The Recency effect is present only in immediate
recall. Auditory gt visual modality --gt
Benjamin's experiment
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Recognition
1. Presenting a list of items of target words 2.
Presenting a list of items containing the target
as well as non-target words 3.Subjects have to
decide which items were old and which items
were new. --gt next experiment
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Saving
1. Presenting a list of CVC-nonsense syllables 2.
Compare the number of repetitions required to
learn the list the first time to the number
required the second time. A handy measure is
percent savings. For example, if it required 20
trials to memorize the list, and only 10 trials
to rememorize it, then this represents 50
savings. --gt next experiment
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Recall vs. Recognition vs. Saving
Saving gt Recognition gt Recall Savings is the
most sensitive test of memory, as it will
indicate some residual effect of previous
learning even when recall and recognition do
not. Savings can be an effective memory test even
after a long delay between learning and testing.
Sometimes Saving and Recognition are the only
ways of testing memory, e.g. memory for smells.
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Rate of learning
Ebbinghaus also found the relation between the
amount of time devoted to learning some material
and the amount of learning/memory of this
material Total time hypothesis The relation
between amount learned and time spent learning
is linear.
Method Savings Learning a list of nonsense
syllables with varying number of
repetitions Re-learning the list 1 day later How
many learning trials would he need to re-learn
the list? --gtThe more time he had spent on
learning the original list the higher was the
saving on the next day.
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Distributed practice
If the total amount of time spent on learning is
distributed over more learning events, memory is
better as if on a single or few learning
event(s). --gt Distribution of practice effect
little and often
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Spaced presentation
If presented with a single item twice, what is
more effective presentation in short
succession or presentation after some
interval? --gt spaced presentation But if the
interval is too long, the (vocabulary) item might
already be forgotten. However, it is more
effective of remembering successfully for oneself
rather than being provided with the item a second
time. Solution Combination of spaced
presentation and immediate recall
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Ideal Vocabulary learning
English Turkish 1-1 1 ? 2-2 2 ? 1 ? 2
? 3- 3 3 ? 1 ? 2 ? 3 ? 4-4 4 ? 3
? 4 ? 1 ? 3 ? 2 ?
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Learning and arousal
In order to learn material explicitly, the
organism has to be conscious With increasing
anaesthesia, learning is impaired. But some
implicit learning may still take
place. Interaction of arousal x time
elapsed For immediate recall For later recall
Explanation High level of arousal consolidates
the memory trace, but only after some time. There
is an immediate short-term penalty on
high-arousal learning.
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Time of learning and time of recollection
Interaction between time of the day when
learning takes place and time of the day when the
material is recollected. For immediate
recall For later recall
Explanation Arousal increases during the day. It
is still low in the morning (good for immediate
recall) and gets higher in the afternoon (good
for delayed recall).
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Repetition and learning
Repetition/rehearsal is important--gt total time
hypothesis But for LTM the organization of the
material is more important - meaning (gestalt),
not superficial features meaning (deep
processing) form/features (shallow
processing) --gt levels of processing hypothesis
(Craik and Lockhart 1972)
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Meaning and memory
-Those nonsense syllables which were more likely
to be associated with a meaningful word were
better learned. --gt meaning facilitates
memory -Items of a list are better retained when
they are embedded in a meaningful story. --gt
experiment remembering a list of words in rote
memory vs. in terms of a meaningful story -When
we retell a story we had previously heard, we do
this in terms of meaning and do not (cannot)
recall the exact words.--gt Barlett (1932) --gtLTM
retains material in terms of meaning Barlett,
Frederick (1932) Remembering. Cambridge CUP.
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Learning and predictability
Verbal material that conforms to the transition
probabilities between words in sentences is
better retained than random material --gt
predictability, redundancy --gt role of syntax
binding together elements to form a higher order
constituent --gt chunking (see Miller 1956, Short
Term Memory)
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Learning and predictability
Cloze technique (Taylor 1953) Technique for
testing the readability of a text. Inspired by
the Gestalt Principle of Closure (tendency to add
missing features so that a closed gestalt
results). Parts of a story were systematically
deleted (e.g., every 5th word). The amount of
correctly guessed words was a reliable indicator
of the text's readability. Taylor, Wilson
(1953) Cloze procedure A new tool for
measuring readability. Journalism Quaterly, 30
(4), 415-433.
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Some Terminology