Memory

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Chapter 8

• Memory

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Memory

• Memory - any indication that learning persists
  over time
• Involves ability to store and retrieve
  information
• Sensory memory - initial recording of information
  in the memory system
• Sensory memory - very fleeting, fraction of a
  second
• Known as sensory registers.

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• Information checks in (registers) in the sensory
  system, but usually immediately checks out
  (within a fraction of a second)
• Sperling - classic experiment
• Sperlings experiment - flashed letters on a
  screen for one-twentieth of a second
• Subjects - write as many of the letters as they
  can recall

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K Z R Q B T S G N
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K Z R Q B T S G N
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• How many could they recall?
• About 50
• Sperling - about to conclude that only 50 of the
  letters registered in sensory memory
• However, before doing so he did one other
  experiment.

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• This time after flashing letters he indicated to
  subjects which row of letters to reproduce
• He did this by sounding either a high, medium, or
  low tone immediately after flashing the letters

High tone - top line,
Medium tone - middle line,
Low tone - bottom line
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K Z R Q B T S G N
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• Could subjects reproduce the row?
• Remember, subjects were not told which row to
  remember until after they had seen the letters
• Results - subjects could almost always reproduce
  the row which they were asked to reproduce
• Now what does Sperling conclude?
• All nine letters registered in sensory memory

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• Sperling used the term iconic memory
• A fleeting photographic memory
• Goal is to take information from sensory memory
  and place it in longer term storage
• Short-term memory - the second level of memory

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Short-Term Memory

• Capacity of STM 7 ? 2 (5 - 9) bits of
  information. Capacity still limited
• For about 3 - 20 seconds (thus, short-term)
• Number examples
• Can we take information from short-term memory
  and place it in long-term memory?

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Long-Term Memory

• Relatively permanent
• Unlimited storage
• Task - to take information from STM and place it
  in LTM
• In order to understand this process, lets look
  at encoding.

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• Encoding - the processing of information
• Automatic encoding - encoding that occurs without
  effort. Example
• Effortful processing - encoding which requires
  attention and conscious effort
• Hermann Ebbinghaus - experiments with nonsense
  syllables such as JIH, BAZ, YOX, SUJ, LEQ
• Ebbinghaus made long lists of these syllables,
  studied them for certain amounts of time, then
  checked recall.

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• Ebbinghauss conclusion The amount remembered
  depends on . . .
• time spent learning
• Also, spacing effect - distributing or spacing
  out study or practice time enhances memory
• Serial position effect - our tendency to recall
  best the first and last items in a list
• However, if we are asked to recall the list much
  later, recall is good for only first items.

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Other Types of Encoding

• 1) Visual encoding - the encoding of picture
  images
• 2) Acoustic encoding - the encoding of sound,
  especially the sound of words
• 3) Semantic encoding - the encoding of meaning
• Two or more types are better than one
• An experiment.

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• What was the purpose of this experiment?
• To demonstrate the difference between acoustic
  and visual encoding
• Which type of encoding was best for retention
  purposes?
• Visual encoding
• However, semantic encoding, although, not a part
  of this experiment is usually superior.

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Semantic Encoding

• Processing information in a meaningful way
• We do this in at least two ways
• 1. Relate information to what we already know
• 2. Relate information to something about
  ourselves. This makes it meaningful
• An experiment.

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S A V A O R E E E G U R S Y A O O D N S F C N E R
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• What was the purpose of this demonstration?
• To show value of semantic encoding
• Ebbinghaus estimated that compared with learning
  nonsense material, learning meaningful material
  only requires one-tenth the effort.

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• Wayne Wickelgren (textbook, page 358) states The
  time you spend thinking about material you are
  reading and relating it to previously stored
  material is about the most useful thing you can
  do in learning any new subject matter.
• Also, this experiment could be a demonstration
  for chunking
• Organizing information into manageable units

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• What you did - chunk this information into one
  unit and this unit was something you already knew
• Example of both chunking and semantic encoding
• Advertisers - telephone numbers
• A seven digit number is hard to remember, so make
  it into a word
• 1 - 800 - HOLIDAY.

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Mnemonic Devices

• Memory aids, especially those that use visual
  imagery and organizational devices
• Chunking is an example of a mnemonic
• Another mnemonic learning Great Lakes by
  learning a retrieval cue
• HOMES

H
- Huron
O
- Ontario
M
- Michigan
E
- Erie
S
- Superior.
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Storing Memories in the Brain

• Where is memory?
• In what form is it stored?
• Lashleys 1950 experiment with rats
• Lashleys conclusion Memories do not reside in
  single specific spots
• More recent research has focused on synaptic
  changes
• Sea snail classically conditioned (with electric
  shock) to reflexively withdraw gills when
  squirted with water.

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• Finding the snail releases the neurotransmitter
  serotonin at certain synapses when learning
  occurs. (seen with powerful microscope)
• First glimpse of what actually happens in NS when
  learning occurred
• These synapses fire together more efficiently
  when learned response is repeated
• Long-Term Potentiation -
• an increase in the firing potential associated
  with neurons involved in the learning.

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Stress Hormones and Memory

• Hormones produced when excited or stressed also
  increase learning and retention
• Emotion triggered hormonal changes help explain
  why we long remember exciting or shocking events
  - a first kiss, an earthquake experience, etc.
• Point to remember strong emotional experiences
  make for strong reliable memories.

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Implicit and Explicit Memories

• Implicit memory - retention without conscious
  recollection
• Explicit memory - memory of facts and experiences
  that one can consciously know and declare
• Hippocampus - a limbic system structure that
  serves as a way station for passing explicit
  memories to long-term storage.
• p. 342-343.

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Retrieval Getting Information Out

• Retrieval cues - along with learning, store a
  cue. Example HOMES
• Context effects - putting yourself in the context
  (environment) in which you learned something may
  enhance recall
• State dependent memory - things we learn in one
  emotional state are sometimes more easily
  recalled when we are again in the same state
  (state dependent memory). (p. 374)

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• Mood congruent memory - tendency to recall
  experiences that are consistent with ones
  current good or bad mood
• Example depressed person
• Retrieval can be an encoding problem
• Look at the following picture and questions.

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• Failure to correctly answer may be due to
  encoding failure - you never processed the
  information
• Failure to remember may be a failure in our
  ability to retrieve
• Example name of a person. You know it is there,
  you just cant retrieve it
• Perhaps, you need a retrieval cue.

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REVIEW
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Memory Construction

• Can you reconstruct memory accurately?
• Assume you witnessed a bank robbery
• You would be interviewed about what you could
  recall
• How accurate would your memory be?
• Misinformation effect - incorporating misleading
  information into ones memory
• Example
• Source amnesia - failure to remember correct
  source.

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Improving Memory