3 stages of processing for manipulation of mental representations:

1
Information-processing approach to memorybasic
framework

• 3 stages of processing for manipulation of mental
  representations
• Encoding (acquisition of info)
• Storage (retention of info)
• Retrieval (recovery of info)

Encoding
Retrieval
time
Storage
2
Episodic memory Encoding processesHow do we
acquire information about episodes?

• Role of repetition / practice
• Role of attention
• Role of intention
• Role of level of processing / elaboration
• Role of organization

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Episodic memory Encoding processesRole of
organization

• Bousfield experiment (1953)
• list with 60 unrelated words
• other list with 60 words from 4 semantic
  categories (animals, boys names, professions,
  vegetables) presented in scrambled order
• two major results
• better recall of words from organized lists
• subjects show tendency to recall words in
  related clusters
• -gt attempt to impose organization on info to
  help understand and remember it
• application learn new names at family
  reunion

4
Benefits of more complex organization at
encoding
Experiment by (Bower, 1969) Presentation of
words with or without visible semantic hierarchy
at encoding
Results demonstration of hierarchy at
learning 65 words recall hierarchy obscured
at learning 19 words recall
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Episodic memory Encoding processesRole of
organization

• people show spontaneous tendency to organize
  material even if no objective principle is
  present in material -gt subjective organization
  (E. Tulving)
• Experiment by Tulving, 1962
• Word list apple bell table coffee school lamp
  car roof potato shoe disk paint
• several learning trials words in different
  orders
• after each learning trial free recall
• major result
• people recall words in same clusters on
  different trials
• e.g. subject 1 always school coffee
• subject 2 always school apple

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Episodic memory Encoding processesRole of
organization
benefits of organization are not limited to
verbal information (Mandler et al.
1976/1977) -gt people remember
location of objects better if organized in a
room (3D organization with floor and ceiling)
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Episodic memory Encoding processesRole of
organization and levels of processing

• General point 1
• research on LoP and on organization shows that
  successful encoding of new information relies on
  linking incoming new information to existing
  semantic knowledge
• e.g. think of Bowers minerals experiment
• -gt organization wont have benefits if no
  existing knowledge about hierarchical
  organization (e.g. metals vs stones)

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Episodic memory Encoding processesRole of
organization and levels of processing

• General point 2
• even though much of what we encode happens
  without intention to memorize (LoP), memory
  performance can still be improved by specific
  attempts to commit new info to memory
• -gt strategic aspects of memory
• (people can actively take control to improve
  memory and avoid failure in specific
  situations)
• e.g. waitress effort in restaurant to keep
  orders from different customers apart
• -gt use of mnemonic strategies

9
Episodic memory Encoding processesRole of
organization and levels of processing

• General point 3
• research on organization and LoP suggests that
  way in which info is encoded also determines how
  it can best be accessed later (i.e. what cues
  will help most)
• e.g. experiment with minerals
• what were the rare metals I saw earlier?
• -gt encoding benefits closely linked to
  retrieval benefits

10
Information-processing approach to memorybasic
framework

• 3 stages of processing for manipulation of mental
  representations
• Encoding (acquisition of info)
• Storage (retention of info)
• Retrieval (recovery of info)

Encoding
Retrieval
time
Storage
11
Episodic memory Can there be failures in
storage processes?

• General observation
• memory failure is not always due to insufficient
  encoding it occurs even when successful encoding
  shown
• failures due to problems
• in storage usually referred
• to as forgetting
• e.g. Ebbinghaus
• forgetting curve

12
Episodic memory Does forgetting occur for real
life episodes?

• What did you do for Thanksgiving last fall?

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Episodic memory Does forgetting occur for real
life episodes?

• study by Friedman deWinstanley (1998) on memory
  for latest Thanksgiving dinner in 500 college
  students
• follow-up of memory for details and vividness
  over 6 months
• Findings
• vividness declines more rapidly at beginning
  of delay
• memory for details also forgotten more
  rapidly first
• gist of event remembered well even after 6
  months e.g where was it, what did you eat,
  unique happenings
• BUT general semantic knowledge of help
• -gt forgetting of episodes follows familiar
  course but not all-or-none phenomenon

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Episodic memory Why do we forget?

• basic question that came up in research on STM vs
  LTM
• Why do we forget??
• i.e. why is information lost from episodic
  memory even when it was properly encoded to start
  out with?
• two major explanations
• - transience / trace-decay
• -gt fading of stored information over time
• - interference
• -gt replacing of stored by new information

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Episodic memory Why do we forget?

• McGeoch (1932) critique of trace-decay theory

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Episodic memory Why do we forget?

• McGeoch (1932) gist of interference theory
• in normal experiments and in real world there
  are always activities or events that intervene
  between encoding and retrieval of information
• -gt these activities produce retroactive
  interference and are critical determinants of
  forgetting not time passage as such

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Episodic memory Forgetting mechanisms

• testing of interference hypothesis in verbal
  learning study by McGeoch MacDonald (1931)
• learning of list with 10 adjectives until
  recalled perfectly
• effects of 10 min delay filled with different
  tasks
• -gt is there retroactive interference?

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Episodic memory Forgetting mechanisms

• testing of interference hypothesis in verbal
  learning study by McGeoch MacDonald (1931)
• two major findings
• type of interpolated activity has clear effect
  on memory performance for previously learnt list
  
• -gt most detrimental effect with similar,
  semantically related material
• application remembering lunch at UCC last
  Thursday
• even subjects in rest condition show some
  forgetting

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Episodic memory Forgetting mechanisms

• even subjects in rest condition show signs of
  forgetting in McGeoch MacDonald s experiment
• Why??
• - answer of early believers interference
  hypothesis
• proactive interference
• i.e. detrimental effect of mental activities /
  learning subjects engaged in before entering
  the experiment

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Episodic memory Forgetting mechanisms

• evidence for proactive interference in list
  learning study with up to 20 different lists
• (Underwood, 1957)

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Episodic memory Forgetting mechanisms

• implications of idea of proactive interference
• forgetting in any given experiment is due in
  part to proactive interference from the subjects
  past language use
• - difficult to test, but prediction possible
• more frequently used words in daily language
  should be more difficult to learn due to higher
  interference
• - findings no convincing evidence to support
  prediction
• also forgetting occurs even for nonsense
  syllables (without prior exposure)
• -gt interference theory cannot explain forgetting
  entirely

22
Testing of interference hypothesis in sleep
study (Jenkins Dallenbach, 1924) mo
re forgetting in students with interpolated study
activity during day -gt support for interference
hypothesis difference cant be due to fading /
trace decay
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Episodic memory Forgetting mechanisms

• problems in interpretation of Jenkins
  Dallenbachs sleep study
• - learning occurred at different times of day
  (not equally good for learning)
• when experiment repeated with sleep during day,
  sleep (as compared to wakening) does not reduce
  forgetting as much
• -gt difference in interference between sleep and
  waking
• not whole story
• -gt benefits of sleep go beyond reducing
  interference
• consolidation

24
Episodic memory Processes working against
forgetting

• basic idea of consolidation
• initial memory representation fragile,
  consolidation makes info resistant against
  forgetting
• changes in brain that allow the mind to retain
  info do not all occur during encoding but
  develop over time (allow info to sink in)
• some physiological / neurochemical processes
  of consolidation tied to natural nocturnal sleep
  cycle
• -gt non-REM sleep thought to be critical
  component for consolidation of info in
  episodic memory

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Episodic memory Processes working against
forgetting
typical pattern of findings in studies examining
effect of sleep on retention of word list (e.g.,
Phihal Born, 1997)
Improvement as compared to pre-sleep testing
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Episodic memory Processes working against
forgetting

• recent advantages in study of physiological and
  molecular processes underlying memory allow
  researcher to study trace decay and consolidation
  without encountering philosophical problem
  pointed out by McGeoch (1932)
• e.g.
• learning-induced protein synthesis and gene
  expression
• -gt require time
• -gt lead to structural changes in synapses
  (change in communication between neurons)
• -gt require brain structure hippocampus for
  episodic memory formation

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Episodic memory Why do we forget?

• interference theory vs consolidation theory
• Which theory is right in explaining forgetting?
• -gt certain that both factors determine degree of
  forgetting when info is processed in episodic
  memory explanations not mutually exclusive
• -gt consolidation likely linked to interference
  processes
• BUT theories traditionally address forgetting at
  different level of explanation (neural vs
  cognitive)

28
Information-processing approach to memorybasic
framework

• 3 stages of processing for manipulation of mental
  representations
• Encoding (acquisition of info)
• Storage (retention of info)
• Retrieval (recovery of info)

Encoding
Retrieval
time
Storage
29
Episodic memory Processes at retrieval

• can memory fail at time of retrieval?
• e.g. think of tip-of-the-tongue phenomenon
• relates to difference between accessibility and
  availability
• Availability is info stored?
• Accessibility can stored info be accessed in
  given situation?

30
Episodic memory Retrieval and interference

• Tulving Psotka experiment (1971)
• Does retroactive interference reflect problems
  in availability vs accessibility?
• initial learning of list of with 24 words from 6
  different categories (e.g. buildings, flowers,
  tools, metals, professions, cars)
• afterwards learning of many additional lists
• How does of additional list affect recall of
  first one?
• -gt answer depends on whether free recall or cued
  recall (with category cues) is used

31
Episodic memory Retrieval and interference

• findings in Tulving Psotka experiment

• typical pattern of interference seen with free
  recall increasingly poorer performance with
  increasing of lists
• when category cues provided (