The Cognitive Approach to Memory

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The Cognitive Approach to Memory

• The first few seconds of memory

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Visual Memory

• How much information can we get from a single
  glimpse?

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George Sperling (1960)

• When stimuli consisting of a number of items are
  shown briefly to an observer, only a limited
  number of the items can be correctly reported.
  The fact that observers assert they can see more
  than they can report suggests the memory sets a
  limit on a processes that is otherwise rich in
  information.

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Experiment 1

• Subjects are presented with a brief glimpse (50
  msec) of letter matrix.
• Asked to give a FULL REPORT.
• 7 (/- 2)

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Experiment 2

• Asked to give a PARTIAL REPORT.
• All letters from any row.

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Conclusion We can see a great deal and can have
access to all the information. However, we can
only recall a portion of the information.
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What is this short term store called?

• Iconic Memory

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How long does Iconic Memory last?

• Determined by adjusting time the cue is given.
• Depends on what you are looking at.
• Brightness effects the decay of Iconic Memory.
• The majority of information decays between 300
  and 500 msec.

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Iconic Memory is Fragile

• Brightness Mask
• Brighter the mask the poorer the performance
• Will only work if shown to the same eye
• Retinal effect

• Pattern Mask
• Brightness doesnt matter
• Will work if mask is shown in opposite eye
• Cortical effect

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What good is Iconic Memory

• Iconic Memory keeps our consciousness from being
  overwhelmed
• We can select the information that is most
  important to us at a given moment

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Is all the information lost?

• Memory traces do last longer than 1 sec.
• Only if RECOGNITION is tested
• Information is available only for 1 sec. under
  FULL REPORT or PARTIAL REPORT conditions.

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Experiment (Phillips, 1971)

• Subject were presented with checkerboard patterns
• After a varied duration the pattern was shown
  again with one cell different
• Same or Different

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What is this short term store called?

• Short-Term Visual Memory

• Not effected by Masking
• Is effected by stimuli complexity
• Brightness effect?

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How long does Recognition Memory last?

• Phillips (1974) showed Recognition Memory could
  last a number of seconds
• Goldstein (1971) showed Recognition Memory could
  last a number of days

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Experiment

• Subjects were shown pictures of a) faces, b) ink
  blots, and c) snowflakes
• Recall was the same out to 48 hours
• 71 faces
• 48 ink blots
• 33 snowflakes

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Conclusion Within the first few seconds of
visual memory a great deal of information is
lost. The time in which the information is held
can be influenced by a number of things.
However, enough information can be held to make a
recognition out to a number of days.
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Auditory Memory

• Does auditory memory or Echoic memory work the
  same as Iconic memory?

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Experiment (Moray 1965)

• Simultaneously presented sequences of consonants
  from four different locations
• When cued to recall one location the estimated
  total amount of material stored was greater than
  when Full Recall was requested
• Same as Sperling

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Experiment 2 (Darwin 1972)

• Four-eared man technique
• Delay of cue (0, 1, 2, 3 or 4 seconds)
• Information was lost after about 4 seconds

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Conclusion

• Echoic memory is similar to Iconic memory in that
  there is more information accessible than can be
  Recalled
• Echoic memory is different in that the trace
  lasts longer than a second
• Echoic memory can be masked (Brightness)

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Physiological Evidence of Echoic Memory

• EEG Study
• Magnetic Mismatch Field (MMF) is a electrical
  brain pattern that is generated by a deviant tone
• MMF will still be generated when the deviant tone
  is withheld out to 9 or 10 seconds

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Summary

• Iconic memory is short lived
• Visual memory can be held longer (Recognition)
• Echoic memory is both similar and different to
  Iconic memory.
• Someone should do a Recognition study with Echoic
  memory