Memory

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Memory
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Modal Model of the Mind

• Three memory stores
• Four Control Processes

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Sensory Memory Store

• Divided into two subtypes
• iconic memory - visual information
• echoic memory - auditory information
• Visual or iconic memory was discovered by
  Sperling in 1960

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Sperlings Experiment

• Presented matrix of letters for 1/20 a second
• Report as many letters as possible
• Subjects recall only half of the letters
• Was this because subjects didnt have enough
  time to view entire matrix? No
• How did Sperling know this?

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Sperlings Experiment

• Sperling showed people can see and recall ALL the
  letters momentarily
• Sounded low, medium or high tone immediately
  after matrix disappeared
• tone signaled 1 row to report
• recall was almost perfect

• Memory for image fades after 1/3 seconds or so,
  making report of entire display hard to do

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• How does Information get from Sensory to STM?
• Who did research in this area?

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Selective Attention

• Also called Preattentive Processing
• Cherry 1953
• Dichotic Listening

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Cocktail Party Effect

• The ability to focus on a single speaker, even if
  there are many speakers, is known as the
  cocktail party effect
• The hearing impaired have a diminished ability to
  focus on one speaker when there are numerous
  contemporaneous sounds
• Recent research aims to separate the audio
  signals so that only the speaker of interest is
  amplified by the hearing aid

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Separation Methods

• Classical methods
• Exploit spectral diversity
• Beamforming
• Assumes speech sources of no interest are in far
  field
• Adaptive Noise Cancellation
• Assumes availability of reference signal (which
  must not contain speech of interest)
• Blind Source Separation, BSS
• Exploit spatial diversity, e.g., speech sources
  must be spatially distinct

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Short Term Memory Store

• Function - conscious processing of information
• where information is actively worked on
• Capacity - limited (holds 7 /- 2 items)
• Duration - brief storage (about 15 - 30 seconds)

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Short Term Memory

• Miller The Magical Number 7, Plus or Minus Two.
• Chunking
• Peterson and Peterson Short Term Retention of
  Individual Verbal Items.

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Maintenance Rehearsal
Allows information to remain in working memory
longer than the usual 30 seconds
Maintenance rehearsal
Working or Short-term Memory
Sensory Memory
Attention
Sensory Input
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Working Memory Model

• Baddeley (1992)
• 3 interacting components

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Working Memory Model

• Visuospatial sketch pad - holds visual and
  spatial info
• Phonological loop - holds verbal information
• Central executive - coordinates all activities of
  working memory brings new information into
  working memory from sensory and long-term memory

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• How does Information get from STM to LTM?
• Who did research in this area?

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Encoding andLevels of Processing

• Craik and Tulving 1975

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More Evidence for Elaboration

• Positive correlation between grades and use of
  elaboration in 5th grade students
• In an experiment, college students assigned to
  use elaboration received higher grades than
  students not taught elaboration

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Ways to Use Elaboration

• Actively question new information
• Think about its implications
• Relate information to things you already know
• Generate own examples of concepts
• Dont highlight passage as you read
• Focus on the ideas in the text

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Long-term Memory SystemsSquire 1993
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Explicit Memory

• Also known as declarative or conscious memory

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Implicit MemoryAlso known as
nondeclarative memoryInfluences your thoughts or
behavior, but does not enter consciousness
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There is biological evidence for these theories
as shown in Pet Scans.
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Modal Model of the Mind

• Three memory stores
• Four Control Processes

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Elizabeth Loftus and John Palmer Memory
Experiment and Hypothesis

• Hypothesis People will remember a car accident
  differently if given different language cues
  (words) about the accident

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Loftus and Palmer Methodology

• Students watched a film of two cars colliding
• Collision was moderate with no broken glass
• Different students asked different questions
  hit, smashed, collided, bumped, contacted

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Loftus and Palmer Results
VERB MEAN ESTIMATE OF SPEED (MPH)
Smashed 40.8
Collided 39.3
Bumped 38.1
Hit 34.0
Contacted 31.8

• People reported the fastest speeds if the
  researchers had used the word smashed in the
  question
• From fastest to slowest reported speeds smashed,
  collided, bumped, hit, and contacted groups

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Loftus and Palmer Results

• One week later, subjects were asked if they had
  seen broken glass
• 32 of subjects asked the smashed question said
  yes 14 of subjects asked the hit question
  said yes

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Loftus and Palmer Results and Implications

• People remember things differently depending on
  the language used to describe an event (e.g.,
  smashed versus hit)
• Misinformation effect

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Role of Time Decay Theory

• Memories fade away or decay gradually if unused
• Time plays critical role
• Ability to retrieve info declines with time after
  original encoding
• Problem Many things change with time.
  Something else may change and actually cause
  forgetting Interference