Memory

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Memory

• Special Lecture
• Kevin Silber
• University of Derby

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Overview

• The aim of this topic is to give you an
  introduction to the cognitive psychology of human
  memory.
• In studying memory, you will look at how we
  (humans) encode, store and retrieve information.
  This information can be either visual or verbal.
• We consider the distinction between short-term
  memory (STM) and long-term memory (LTM).
• In this lecture we look in details at short term
  memory.

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Learning Objectives

• By the end of this topic you will be able to
• Understand what is meant by the encoding, storage
  and retrieval of information.
• Understand the distinction between STM and LTM.
• Understand the distinction between semantic and
  episodic memory.

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What Is Memory?

• Memory is a set of processes that allow us to
  encode, store and retrieve information.
• William James believed that there were three
  types of memory store
• Sensory memory
• Short term memory
• Long term memory

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What Is Memory?

• If you were in any doubts as to just how
  phenomenal our memory is, on the next slide I
  will ask you to recall something.
• I will give you a minute to recall as much about
  this thing as possible.

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What Is Memory?

• Try to remember the last meal that you had at a
  restaurant

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What Is Memory?

• Did you recall what the meal was?
• Did you recall the restaurant and features about
  it?
• Did you recall who you were with?
• What else did you recall?

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What Is Memory?

• Given that I could have asked you just about
  anything, you have to admit that this memory
  retrieval system is pretty impressive
• It is no wonder that psychologists have wanted to
  find out just how this instantaneous retrieval
  processing is achieved
• But to do that we must also consider how the
  information gets in in the first place and then
  how it is stored

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Psychological Approaches to the Study of Memory

• Given James distinction between the three types
  of memory, psychologists have asked a number of
  questions
• How long does each type last?
• How much information can be stored in each type?
• What is the nature of the processing for each
  type?

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Sensory Memory

• There is believed to be a sensory store to
  accompany each of the five senses.
• However, the iconic (visual) and echoic
  (auditory) stores have been most studied.
• Sperling (1960) did the following study on the
  iconic store.

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Sensory Memory

• Look at the x below

P B S R W O V U G
X
X
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Sensory Memory

• What letters do you remember seeing?
• This is the pattern of letter you saw.
• How many did you get right?

P B S R W O V U G
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Sensory Memory

• The capacity of sensory memory is thought to be
  the same as for the sensory system itself
• The estimates of the duration of sensory memory
  vary but range from 0.5 to 1 second for iconic
  memory (Sperling) to about 4 to 5 seconds for
  echoic memory.

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Primary and Secondary Memory

• James described the main types of memory as
  primary memory and secondary memory
• Primary memory is what is in the here and now so
  is the equivalent of short term memory
• Secondary memory is described as the memory of
  the past and so equates to long term memory
• What evidence is there that these two types of
  memory are distinctive?

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The Serial Position Curve

• I am going to give you a sequence of 20 words
• At the end, I will give you some time to write
  down as many as you can remember
• You can write them down in any order
• Are you ready?

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Now write down as many words as you can remember
desk
shirt
ball
kerb
stick
piano
house
ball
clock
tree
lamp
door
case
carrot
radio
dog
bed
school
shampoo
bus
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The Serial Position Curve

• Here are the words you saw
• Lets see which ones people remembered
• The next slide shows a graph of what we should
  have got (it is a 25 item version)

desk shirt ball kerb stick piano house ball clock
tree lamp door case carrot radio dog bed school sh
ampoo bus
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The Serial Position Curve
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The Serial Position Curve

• The curve has a recency effect where you remember
  the final few items.
• This is attributed to a direct output from STM.
• It has a primacy effect where you remember the
  first few items.
• This is attributed to the first few items having
  been rehearsed into LTM.
• It has an asymptote where recall is poor in the
  middle.
• This is because the items could not be rehearsed
  and so failed to be transferred into LTM.

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Evidence from Neuropsychology

• What evidence is there that the two stores are
  truly separate.
• We can look to brain damage for the verification
• Patient KF had an intact LTM but a badly impaired
  STM
• Patients with Korsakoff syndrome have the
  reverse.
• This separation is called a double dissociation

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The Modal Model

• Atkinson and Shiffrin (1968) put together the
  evidence that had been collected into a model
  they called the Modal Model
• The model was revised slightly in 1971.
• The next slide presents the model.

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The Modal Model
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The Modal Model

• In the model, STM has a short capacity (7 /- 2
  according to Miller, 1956)
• Rehearsal is the key to transferring information
  from STM to LTM
• LTM has an unlimited capacity
• Forgetting from STM occurs via displacement but
  information is never really forgotten from LTM
  the problem is one of retrieval

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Problems with the Modal Model

• If rehearsal is needed for transfer from STM to
  LTM then how can people have an intact LTM and a
  deficit in STM as in patient KF?
• Also, the idea of a singular STM does not take
  account of differences in STM recall for
  different types of information.

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Working Memory

• An alternative model to the Modal Model was
  presented by Baddeley and Hitch in 1974

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Summary

• We have seen what a fascinating process memory is
• We have explored the main types of sensory memory
  (echoic and iconic)
• We have looked at the distinction between STM and
  LTM
• The concept of working memory has been introduced