PowerPointPrsentation

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Cognitive Psychology Spring 2005 -Discussion
Section-
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Cognitive functions

• Perception

Emotion Motivation Action

• Attention

• Memory

• Memory

• Imagery

• Decision-making

• Reasoning, problem-solving

• Language

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A very mixed blessing
Memory is becoming popular

• Memento (2000)
• Finding Nemo (2003)
• Eternal Sunshine of the Spotless mind (2004)
• 50 first dates (2004)

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Memory I. Short term memory
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Types of memory
Basic classification based on longetivity of
storage, not qualitative aspects (after
Shiffrin Atkinson, 1975)

• Ultra-short term memory (sensory register)

• Short term memory (Working memory)

• Long term memory (Episodic, Semantic, Procedural,
  etc.)

All of them have relatively well established
physiological correlates
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Short term memory

• Demo

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9 5 0 1 2 3
6 0 6 8 4 8 6
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8 9 1 3 7 6 2 1
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4 5 6 5 0 1 8 5 8
9 2 1 8 7 3 8 2 1 7
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Short term memory

• Demo

9 5 0 1 2 3
6 0 6 8 4 8 6
8 9 1 3 7 6 2 1
4 5 6 5 0 1 8 5 8
9 2 1 8 7 3 8 2 1 7
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? Characteristics of STM

• Information available in absence of the stimulus

• Information is not stored indefinitely. Vanishes.

• There is a capacity limit. The short term storage
• cant keep large amounts of information active.

• The retained information is in a highly sensory-
• Based format. Little abstraction/distortion.

• There are characteristical memory-effects. STM
• profits highly from memorization strategies.

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Capacity of STM

• 7 /- 2 items (G.A. Miller, 1956)

• Improved by chunking. Chunking allows to improve
  the objective capacity of STM

• 7 7 3 8 3 4 3 0 7 2

• 773-834-3072

• Chunking is a form of re-coding of the sensory
• Information. Profits from identification, LTM

• C I A F B I K G B S D I M A D

• C I A F B I K G B S D I M A D

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Retention duration

• Basic retention time is roughly 20 seconds.

• Improved by rehearsal. Continuous rehearsal can
• basically extend the retention duration
  indefinitely.

• Moreover, rehearsal can also facilitate the
  trans-
• tormation of the information from STM to LTM.

• Another strategy to improve retention is sensory
• recoding (Silent) speaking, writing, etc.

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Coding

• Mental representation is sensory, particularly
  acoustic for language material.

• ? Things are encoded in terms of how they
• sound, not what they look like or mean.

• Classical studies People were given material to
• remember and then given confusing material on a
  test
• They were confused by items that sounded similar,
  not by items that mean similar things.

• This effect might be highly material-, task-, and
• strategy-dependent.

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STM effects

• Almost all information that goes into STM is
• subject to the so-called Primacy- and
  Recency-Effect.

• This effect means that information at the
  beginning and at the end of the list has a
  retention advantage

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STM effects

• Interference An alternative explanation for
• forgetting, vs. decay.

• Basic idea Some information displaces others in
  capacity
• limited STM. ? Alternative explanation for
  retention duration, as a side-effect of capacity
  limitations.

• Proactive interference Material learned first
  disrupting
• retention of subsequently learned material.
• Retroactive interference Material learned later
  disrupting
• retention of previously learned material.

Both effects explain why cramming is a bad idea.
Ineffective.
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Information retrieval

• Information retrieval is the complementary step
  to
• Information encoding.

• Saul Sternberg (1966) Information retrieval is
  serial and exhaustive The higher the number the
  distractors there are, the longer it takes the
  whole set is searched.

• Classical effects might be content-dependent ?
  Parallel search possible.

• Homework Watch Brazil (1985).

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Working memory

• Typical inflation of words, in memory field.
  Inspired
• by computer science. Term goes back to Baddeley.

• Means That short term memory has a substructure.

Central executive
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Memory II. Long term memory
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Characteristics of LTM
STM
LTM

• Very long, potentially life-long.

• Virtually unlimited, hard to study, hard to
  quantify.

• Semantic, conceptual coding.
• Retained is the gist, the meaning of
• information that was learnt.

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Structure of LTM
LTM
The real deal? Methods matter. Example
Experimental evidence for decontextualisation.
A gradient, vs. categorical
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Some brain facts about memory...

• Declarative vs. Procedural has a brain basis
  (Neocortex vs. Cerebellum).

• Most of the back part of the brain
• (posterior part) involved in LTM.

• Exact coding principle is unknown. Many theories
  (holistic, etc.). In general, we know much less
  about the biological basis than about the biol.
  basis of STM.

• Processing tissue Storing tissue. Not like in
  Computers. This has important implications...

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Basic memory processes
Encoding
Storage
Retrieval
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Encoding
Information can be encoded on different levels
Encoding of meaning is usually more stable Than
encoding for physical attributes.
Levels of Processing theory. Critique Highly
dependent on retrieval task.
Encoding into LTM generally by paying attention,
rehearsal.
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Storage LTM Forgetting due to
Decay and/or loss of retrieval cues
Interference
OVERWRITING
Each information retrieval is a new encoding.
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Principles of Information retrieval

• Categorization Subjects generally recall lists
  in the order of their internal categories.

• Encoding specificity Retrieval is easier if the
  context of retrieval matches the context of
  encoding as close as possible.

? Context effect, mood/state-dependent memory.

• Cues Memory retrieval is best, if as many cues
  as possible are attached to a given memory
  (spacing), but as few as possible memories to any
  given cue.

Bad
Good
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Eye-witness memory
Elizabeth Loftus, Lady Eye-witness memory
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Eye-witness memory
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Eye-witness memory
Blue van or red car?
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Eye-witness memory
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Eye-witness memory
Red hair or bald?
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Eye-witness memory
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Eye-witness memory
Black boots or sandals?
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Eye-witness memory

• Not really reliable

• Fallible to distortions, information that was
  introduced later. (due to constructive nature of
  memory overwriting).

• Likely cause Source memory failure

• Can be offset by paying attention to relevant
  things.

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Flashbulb memories

• Characteristics
• Extremely vivid
• High personal confidence of accuracy
• Usually for rare events of personal significance.

• Examples
• 9/11
• Tschernobyl
• Princess Diana
• ...

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Flashbulb memories

• Surprisingly, they are NOT much more accurate
  than other memories, just more memorable.

• They do NOT form a special system, vividness can
  be explained by basic memory mechanisms

-Attention (Relevance) -Rehearsal -Lack of
interference -Spacing

• No inflation of concepts ? Good science.

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Repressed memories

• A hot issue since the mid 90s. Number of
• Cases exloded. ? Into the thousands.

• People have been sued and convicted
• Of ghastly crimes (often involving relatives)

• Usually based on concept of repression
  (Introduced by Freud).

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Repressed memories

• While it is impossible to tell in an invididual
  case, some things are very troubling...

• Scientific concept of Repression is extremely
  shaky. No evidence that it can happen. In fact,
  the opposite seems to be true (PTSD)

• It has been shown that very vivid memory can be
  implanted into the minds of both adults and
  children. The subjects cant discriminate real
  vs. implanted memories.

• The process of recovery (recovery therapy) is
  very similar to the process used for artificial
  implantation.

• Evidently wrong recovered memories seem to be
  progressive, ? the reports of the abuse get more
  and more severe over time.

• People who solidly claim that they were abducted
  by space aliens and similarly outrageous stories
  usually have bad source memory.

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The seven sins of memory by Dan Schacter
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What are the seven sins?

• Pride
• Envy
• Gluttony
• Lust
• Anger
• Greed
• Sloth

• Transience
• Absentmindedness
• Blocking
• Misattribution
• Suggestibility
• Bias
• Persistence