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Cognitive Processes
PSY 334
Chapter 5 (Cont.)
Chapter 6 – Human Memory:
Encoding and Storage
July 29, 2003
Psychological Reality of
Schemas
 Brewer & Treyens – subjects left in a
room for 35 sec, then asked to list what
they saw there:
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Good recall for items in schema
False recall for items typically in schema
but missing from this room.
29/30 recalled chair, desk; 8 recalled skull
9 recalled books when there were none
Degrees of Category
Membership
 Members of categories can vary
depending on whether their features
satisfy schema constraints:

Gradation from least typical to most typical.
 Rosch – rated typicality of birds from 1-7:
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Robin = 1.1
Chicken = 3.8.
 Faster judgments of pictures of typical
items, higher sentence-frame ratings.
Disagreements at Category
Boundaries
 McCloskey & Glucksberg – subjects
disagree about whether atypical items
belong in a category:
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30/30 apple is a fruit, chicken is not a fruit
16/30 pumpkin is a fruit
Subjects change their minds when tested
later.
 Labov – boundaries for cups and bowls
change with context.
Event Concepts (Scripts)
 Schank & Abelson – stereotypic
sequences of actions called scripts.
 Bower, Black & Turner – script for going
to a restaurant.
 Scripts affect memory for stories:
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Story elements included in script well
remembered, atypical elements not
recalled, false recognition of script items.
Items out of order put back in typical order.
Two Theories
 What happens mentally when we
categorize?

Two theories are being debated.
 Abstraction theory -- we abstract and
store the general properties of instances.

Prototype theory.
 Instance theory -- we store the multiple
instances themselves and then compare
average distances among them.
Neural Nets for Learning
Schemas
 Gluck & Bower – designed a neural net
that abstracts central tendencies without
storing instances.
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Patients with four symptoms classified into
two hypothetical diseases.
One disease 3 times more frequent than
the other.
Error correction changes the strength of
associations in the network (delta rule).
 Model predicted subject decisions well.
Evidence From Neuroscience
 People with temporal lobe deficits
selectively impaired in recognizing
natural categories but not artifacts (tools)
 People with frontoparietal lesions
unaffected for biological categories but
cannot recognize artifacts (tools).
 Artifacts may be organized by what we
do with them whereas biological
categories are identified by shape.
Bartlett’s War of the Ghosts
 Demo
Cognitive Processes
PSY 334
Chapter 6 – Human Memory:
Encoding and Storage
July 29, 2003
Ebbinghaus
 First rigorous investigation of human
memory – 1885.
 Taught himself nonsense syllables

DAX, BUP, LOC
 Savings – the amount of time needed to
relearn a list after it has already been
learned and forgotten.
 Forgetting function – most forgetting
takes place right away.
Memory Models
 Atkinson & Shiffrin – proposed a three-
stage model including:

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Sensory store – if attended goes to STM
Short-term memory (STM) – if rehearsed
goes to LTM
Long-term memory (LTM)
 No longer the current view of memory.

Still presented in some books.
Criticisms of STM
 Rate of forgetting seemed to be quicker
than Ebbinghaus’s data, but is not really.
 Amount of rehearsal appeared to be
related to transfer to long-term memory.
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Later it was found that the kind of
rehearsal matters, not the amount.
Passive rehearsal does little to achieve
long-term memory.
 Information may go directly to LTM.
Depth of Processing
 Craik & Lockhart – proposed that it is not
how long material is rehearsed but the
depth of processing that matters.
 Levels of processing demo.
Working Memory
 Baddeley – in working memory speed of
rehearsal determines memory span.
Articulatory loop – stores whatever can
be processed in a given amount of time.
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Word length effect: 4.5 one-syllable words
remembered compared to 2.6 long ones.
1.5 to 2 seconds material can be kept.
Visuospatial sketchpad – rehearses
images.
Central executive – controls other systems.
Delayed Matching Task
 Delayed Matching to Sample – monkey
must recall where food was placed.
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Monkeys with lesion to frontal cortex
cannot remember food location.
Human infants can’t do it until 1 year old.
 Regions of frontal cortex fire only during
the delay – keeping location in mind.
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Different prefrontal regions are used to
remember different kinds of information.