Chapters 5: Memory Models and Research Methods

Memory Is …The mechanism we use to create, maintain and retrieve information about the past

• Processes in Memory
  • Encoding
    • Processes used to store information in memory
  • Storage
    • Processes used to maintain information in memory
  • Retrieval
    • Processes used to get information back out of memory

I. TASKS USED FOR MEASURING MEMORY

A. Recall versus Recognition Task

• Recall Tasks
  • Free Recall
    • Recall all the words you can from the list you saw previously
  • Cued Recall
    • Recall everything you can that is associated with the Civil War
    • Participants are given a cue to facilitate recall
  • Serial Recall
    • Recall the names of all previous presidents in the order they were elected
    • Need to recall order as well as item names
• Recognition Tasks
  • Circle all the words you previously studied
  • Indicate which pictures you saw yesterday
  • The participant selects from a list of items they have previously seen

B. Implicit versus Explicit Memory Task

• Explicit memory tasks
  • Involves conscious recollection
  • Participant knows they are trying to retrieve information from their memory
• Implicit memory tasks
  • Require participants to complete a task
  • The completion of the task indirectly indicates memory
• Implicit Memory Tasks

Participants are exposed to a word list (Priming)

Tiger

Lion

Zebra

Panda

Leopard

Elephant

After a delay…

Participants then complete word puzzles, they are not aware they are a type of memory test

Word fragment Completion:

C_E_TA_

E_E_ _A_ N_

_ E _ R A

Word Stem Completion:

Mon _____

Pan_____

• 1. Explicit Memory
• 2. Implicit Memory
• 3. Priming

II. TRADITIONAL MODEL OF MEMORY

Atkinson & Shiffrin's 3 Stage Model of Memory

• A. Sensory Store
  • 1. Iconic Store
    • Sperling (1960) Iconic Memory Research
      • Whole report procedure
        • Flash a matrix of letters for 50 milliseconds
        • Identify as many letters as possible
        • Participants typically remembered 4 letters
      • Partial Report Procedure
        • Flash a matrix of letters for 50 milliseconds
        • Participants are told to report bottom row
        • Participants were able to report any row requested
  • Sensory Stores
    • Iconic store or Visual sensory register
      • Holds visual information for 250 msec longer
      • Information held is pre-categorical
      • Capacity &endash; up to 12 items
      • Information fades quickly
    • Econ or Auditory sensory register
      • Holds auditory information for a 2-3 seconds longer to enable processing
• B. Short-term store
  • Attention
    • Attend to information in the sensory store, it moves to STM
  • Rehearsal
    • Repeat the information to keep maintained in STM
  • Retrieval
    • Access memory in LTM and place in STM
  • Research on Short-Term Memory
    • Miller (1956) (Magic Number &)
    • Examined memory capacity
    • 7+/- 2 items or "chunks"
  • Chunking -- organize the input into larger units
    • 1 9 8 0 1 9 9 8 2 0 0 3 - Exceeds capacity
    • 1980 1998 2003 - Reorganize by chunking.
• C. Long-term store
  • Capacity
    • Thus far limitless
  • Duration
    • Potentially permanent
  • Bahrick's Research on Very Long Term Memory
    • High school year books containing all of the names and photos of the students were used to assess memory
    • 392 ex-high school students (17-74) took 4 different memory tests:
    • Free recall of the names
    • A photo recognition test where they were asked to identify former classmates
    • A name recognition test
    • A name and photo matching test
    • For some of the participants, it was as long as 48 years since they graduated from High school
  • Bahrick et. al., (1975) Results
    • 90% accuracy in face and name recognition after 34 years
    • 80% accuracy for name recognition after 48 years
    • 40% accuracy for face recognition after 48 years
    • 60% accuracy for free recall after 15 years
    • 30% accuracy for free recall after 30 years
• D. Hypothetical Constructs

III. LEVELS OF PROCESSING MODEL

Craik & Lockhart's Level of Processing Model

• Different ways to process information lead to different strengths of memories
• Deep processing leads to better memory; elaborating according to meaning leads to a strong memory
• Shallow processing emphasizes the physical features of the stimulus; the memory trace is fragile and quickly decays
• Distinguished between maintenance rehearsal and elaborative rehearsal
• Support for Levels of Processing
  • Craik & Watkins (1973)
    • Participants listened to lists of words
    • Task was to recall the last word in the list which began with a particular letter
    • The number of intervening words between words beginning with the target letter was varied
  • Craik & Watkins (1973) Results
    • Recall of words was independent of the length of time (the number of intervening words) it was maintained in STM
    • Conclusion: Maintenance rehearsal did not automatically lead to LTM
    • Levels-of-Processing Interpretation: Students rehearsed the words without elaborating on the meaning of the words, only concentrating on the initial consonant sound&emdash;rehearsing at a shallow level
  • Craik & Tulving (1975)
    • Participants studied a list in 3 different ways
      • Structural: Is the word in capital letters?
      • Phonemic: Does the word rhyme with dog?
      • Semantic: Does the word fit in this sentence? The ______ is delicious.
    • A recognition test was given to see which type of processing led to the best memory
  • Craik & Tulving (1975) Results
    • Deeper processing led to better memory
  • Criticisms of LOP Model
    • Circular definition of levels
    • Transfer appropriate processing effect
  • Morris, Bransford, and Franks (1977)
    • Two processing tasks: semantic vs. rhyme
    • Two types of tests: standard yes/no recognition vs. rhyme test 
    • Memory performance also depends on the match between encoding processes and type of test (elaboration)

IV. AN INTEGRATIVE MODEL: WORKING MEMORY

Baddeley's Working Memory Model

• Articulatory Loop
  • Used to maintain information for a short time and for acoustic rehearsal
• Visuo-spatial Sketch Pad
  • Used for maintaining and processing visuo-spatial information
• Episodic Buffer
  • Used for storage of a multimodal code, holding an integrated episode between systems using different codes
• Central Executive
  • Focuses attention on relevant items and inhibiting irrelevant ones
  • Plans sequence of tasks to accomplish goals, schedules processes in complex tasks, often switches attention between different parts
  • Updates and checks content to determine next step in sequence of parts
• Working Memory Model Support
  • Baddeley (1986)
    • Participants studied two different list types
      • 1 syllable: wit, sum, harm, bay, top
      • 5 syllables: university, opportunity, aluminum, constitutional, auditorium
    • Reading rate seemed to determine recall performance
    • Supports conceptualization of an articulatory loop
  • Visuo-spatial Sketch Pad
    • Dual-task paradigm
    • Sketchpad can be disrupted by requiring participants to tap repeatedly a specified pattern of keys or locations while using imagery at the same time

V. MULTIPLE MEMORY SYSTEMS

• Tulving's Multiple Memory Systems Model
  • Semantic Memory
    • General knowledge
    • Facts, definitions, historical dates
  • Episodic Memory
    • Event memories (first kiss, 6th birthday)
  • Procedural Memory
    • Memories on how to do something (skiing, biking, tying your shoe)
  • Multiple-Memory Systems Model Support
    • Nyberg, Cabeza, & Tulving (1996)
      • PET technology to look at episodic and semantic memory
      • Asked people to engage in semantic or episodic memory tasks while being monitored by PET  
    • Results 
    • Left (hemisphere) frontal lobe differentially active in encoding (both) and in semantic memory retrieval
    • Right (hemisphere) frontal lobe differentially active in retrieval of episodic memory
• Figure 5.6--taxonomy of memory

VI. A CONNECTIONIST PERSPECTIVE

• McClelland & Rumelhart's Connectionist Model
  • Parallel distributed processing model
    • Memory uses a network
      • Meaning comes from patterns of activation across the entire network
    • Spreading Activation Network Model
      • Supported by priming effects
  • Results
    • Koriat & Goldsmith (1996)
      • Suggest a change in the metaphors used to conceptualize memory
      • Propose a correspondence metaphor
      • Emphasize function of memory
      • Emphasize how memory works in real world

VII. MEMORY IN THE REAL WORLD

• A. Storehouse
• B. Correspondence

VIII. EXCEPTIONAL MEMORY AND NEUROPSYCHOLOGY

• Case studies of mnemonists
  • S. (Luria, 1968)
    • Long strings of words
    • Remembered over 15-18 years
  • Rajan Mahadevan
    • Can recite pi to 31,811 places
    • No forgetting on matrices up to 20x20 digits
• Deficient Memory
  • Amnesias
    • Retrograde Amnesia
      • Loss of memory for events that occurred before the trauma
    • Infantile Amnesia
      • Inability to recall events of young childhood
    • Antereograde Amnesia
      • No memory for events that occur after the trauma
  • Amnesia Studies
    • Study antereograde amnesiacs using implicit and explicit memory tests
    • Amnesiacs show normal priming (implicit), but poor recognition memory (explicit)
    • They did not remember having seen the word list, but completed the word fragments at the same rate as normals
  • Alzheimer's Disease
    • Leads to memory loss and dementia in older population
    • Atrophy of the cortical tissue
    • Alzheimer brains shows abnormal fibers that appear to be tangles of brain tissue and senile plaques (patches of degenerative nerve endings)
    • The resulting damage of these conditions may lead to disruption of impulses in neurons
    • Over the age of 65 are labeled 'late onset'
    • 'Early onset' is rare but can affect those in their mid 30's and in middle age
    • Symptoms (Gradual, Continuous & Irreversible)
      • Memory loss
      • Problems doing familiar tasks
      • Problems with language
      • Trouble knowing the time, date, or place
      • Poor or decreased judgment
      • Problems with abstract thinking
      • Misplacing things often, such as keys
      • Changes in mood and behavior
      • Changes in personality
      • These symptoms could be an early sign of Alzheimer's when it affects daily life
  • Hippocampus
    • Critical for integration and consolidation
    • Essential for declarative memory
      • Without the hippocampus only the learning of skills and habits, simple conditioning, and the phenomenon of priming can occur