PS2505 Cognition Lecture 3 by n3NYd0M

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									     Core Features of Episodic Memory
   (1) Memory for specific events from your past

   (2) Involves retrieving the bound together contents and
    context (what happened, when it happened and where did it
    happen)

   (3) Associated with a particular kind of conscious
    experience
       ‘mental time travel’
       re-experiencing past sights, sounds, etc
            Episodic Memory Mechanisms
            Perceptual                                     Perceptual
Semantic                                       Semantic
             Records     Context                            Records     Context
Records                                        Records


             Binding                                        Binding


           Encoding                Storage                Retrieval


  Attentional                  Consolidation                     Attentional
   Control                     Mechanisms                         Control
                  Aims of Lecture 3

   (1) How the core features are investigated in lab-based
    experiments that strip EM down to its basic elements.

   (2) How does EM differ from other forms of long term
    memory?

   (3) What don’t we know about episodic memory?
           Amnesia

       Retrograde Anterograde



Past                            Future
Childhood (Anterograde) Amnesia
   Vargha-Khadem et al, Science (1997)
      Three amnesic children
         Beth: birth: perinatal anoxic episode, seizures
         Jon: age 4: seizures
         Kate: age 9: drug overdose, inducing seizures


   Disabling memory problems with every-day life
     Spatio-temporal (i.e. Episodic!)


   But ‘normal’ intellectual development
Questions Asked by Varga-Khadem

   (1) What kind of brain damage was present?

   (2) What kind of memory has been lost?
    » Which cognitive processes are no longer functioning?


   (3) What kind of memory is still intact?
Methods Used by Varga-Khadem et al

    Functional brain imaging to reveal brain damage

    Standard neuropsychological tests of general intellectual
     and memory function to establish the clinical profile

    Experimental Cognitive Tests of item and associative
     recognition
Common Underlying Brain Damage

   Selective bilateral (left and right) atrophy of the
    hippocampal formation
Standard Neuropsychological Tests of
 Intellectual and Memory Functions
    Speech, language, IQ, etc, all within normal range
    Immediate recall normal (intact short term working
     memory)
    Delayed recall severely impaired

    A clinical profile consistent with a dense and
     selective anterograde amnesia
Experimental Cognitive Tests of Memory
     Item and associative recognition for

       Nonwords (eg FLUNT)
       Faces
       Nonword pairs
       Face pairs
       Voice-face pairs
       Object-place pairs
 Study Phase


         BLUE

TOP
                CAT

                      SHOE

                         DROP
Recognition Test Phase

NEW!



             BLUE
       TOP
                    DOG

                          SHE

                                AIR
               Performance on the
            Cognitive Tests of Memory

TYPE OF STUDY ITEM        ITEM       ASSOCIATIVE
                       RECOGNITION   RECOGNITION

     Nonwords            INTACT        INTACT
       Faces             INTACT        INTACT
  Object-place pairs        ---       IMPAIRED
   Voice-face pairs        ----       IMPAIRED
             General Conclusions
   Selective and generalised loss of episodic memory
    function
     » The episodic memory failure may reflect an
       inability to bind (associate) qualitatively
       different kinds of information together.

   Intact ability to recognise must be based on a non-
    episodic form of memory.
     Core Features of Episodic Memory

   (1) Memory for specific events from your past

   (2) Involves retrieving the bound together contents and
    context (what happened, when it happened and where did it
    happen)

   (3) Associated with a particular kind of conscious
    experience
       ‘mental time travel’
       re-experiencing past sights, sounds, etc
            Episodic Memory Mechanisms
            Perceptual                                     Perceptual
Semantic                                       Semantic
             Records     Context                            Records     Context
Records                                        Records


             Binding                                        Binding


           Encoding                Storage                Retrieval


  Attentional                  Consolidation                     Attentional
   Control                     Mechanisms                         Control
                  Encoding Specificity

   How are memory traces accessed by retrieval ‘cues’?
    » Introduced by Tulving and Thompson, in 1973.



   The most effective ‘retrieval pathways’ reinstate processing
    that occurred when the target information was encountered.
      How Encoding Specificity Works
   From Fisher and Craik (1976) (see Reisberg, pp176-177)

    » Subjects studied word-pairs
       – The encoding task emphasised a relationship based either on
         meaning (‘CAT-DOG’) or on sound (‘CAT-HAT’)


    » And performed ‘associative recall’ tasks
       – Can you recall a studied word associated with ‘CAT’?
       – Can you recall a studied word sounding like ‘CAT’?
Fisher and Craik’s Findings

50
45
40
35
30
                              MEANING CUE
25
                              SOUND CUE
20
15
10
 5
 0
     ENCODE    ENCODE SOUND
     MEANING
     Various Encoding Specificity Effects
50                                                 40
45                                                 35
40
                                                   30
35
30                                                 25                               RETRIEVE ON
                                    MEANING CUE                                     LAND
25                                                 20
                                    SOUND CUE                                       RETRIEVE
20                                                 15                               UNDERWATER
15
                                                   10
10
 5                                                 5
 0                                                 0
       ENCODE       ENCODE SOUND                        ENCODE ON     ENCODE
       MEANING                                            LAND      UNDERWATER


90                                                 30
80
                                                   25
70
60                                                 20
                                   SAD RETRIEVAL                                      PLACEBO
50                                                                                    RETRIEVAL
                                                   15
40                                 HAPPY                                              DOPE
                                   RETRIEVAL       10                                 RETRIEVAL
30
20
                                                   5
10
0                                                  0
     SAD ENCODING    HAPPY                               PLACEBO    DOPE ENCODING
                    ENCODING                             ENCODING
                 Encoding Specificity

   Memory performance is best when there is overlap in the
    conditions at encoding and retrieval.

   Nothing is encoded in isolation, information is always
    encoded within a ‘context’, including
    » The external spatiotemporal context (time and place)
    » Your internal thoughts and feelings while the information is
      processed.
            Episodic Memory Mechanisms
            Perceptual                                     Perceptual
Semantic                                       Semantic
             Records     Context                            Records     Context
Records                                        Records


             Binding                                        Binding


           Encoding                Storage                Retrieval


  Attentional                  Consolidation                     Attentional
   Control                     Mechanisms                         Control
     Core Features of Episodic Memory
   (1) Memory for specific events from your past

   (2) Involves retrieving the bound together contents and
    context (what happened, when it happened and where did it
    happen)

   (3) Associated with a particular kind of conscious
    experience
       ‘mental time travel’
       re-experiencing past sights, sounds, etc
  His face
is familiar...
                 When episodic memory fails.....

                              HEY BUDDY,
                             I MISSED YOU
                               SO MUCH....
Recollection Contrasted With Familiarity
   Only recollection, the retrieval of episodic details, can
    provide information about the ‘source’ of a memory.

   Familiarity can arise for a number of reasons, and can
    support recognition judgements even when recollection
    fails - hence it can be prone to error.

   It is possible that Varga-Khadem’s patients may have been
    utilising the familiarity of studied items as a basis for their
    intact recognitions.
      Modified Recognition Procedures
   Remember / Know Judgements
    » Ask subjects to report on their experiences while recognising.
    » Do they ‘Remember’ any episodic details
    » Or do they just ‘know’ the information was encountered at study.


   These cognitive processes supporting remember and know
    responses are not identical.
    » E.g. only ‘remember’ responses are reduced when attention is
      divided.

								
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