Short and Long-term Memory Flashcards

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1
Q

Define coding (encoding).

A

The way information is changed so that it can be stored in memory.

Enters through senses, stored as visual codes (pictures), acoustic codes (sounds) or semantic codes (meaning of experience).

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2
Q

Define duration.

A

A measure of how long a memory lasts before it is no longer available.

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3
Q

Define Long-term memory (LTM).

A

Your memory for events that have happened in the past

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4
Q

What is the duration, capacity and coding of LTM?

A

Can last anywhere from 2 minutes to 100 years - unlimited

Unlimited capacity

Tends to be coded semantically

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5
Q

Define short-term memory.

A

Your memory for immediate events.

Measured in seconds and minutes rather than hours and days.

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6
Q

What is the duration, capacity and coding of the STM?

A

Short duration (unless rehearsed)

Limited capacity of about 4 items or chunks

Tends to be coded semantically

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7
Q

Define capacity.

A

This is the measure of how much can be held in memory.

Represented in terms of bits of information, e.g. number of digits

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8
Q

What experiment tests the duration of the STM?

A

Peterson and Peterson

Trigram Experiment

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9
Q

What were the aims of the Peterson and Peterson trigram experiment?

A

Information held in the STM appears within about 20 seconds if rehearsal is prevented

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10
Q

What was the procedure of the Peterson and Peterson Trigram Experiment?

A
  • 24 students in a lab
  • researcher called out 3 letters followed by 3 numbers
  • students counted down in thread from number read out
  • after a certain period of time (3,6,9,12,15 or 18 seconds) researcher says stop
  • students have to say the 3 letters they started with
  • researcher wrote down their response
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11
Q

What were the findings of the Peterson and Peterson trigram experiment?

A

90% of trigrams were recalled after 3 seconds

50% of trigrams were recalled after 6 seconds

Less than 10% recalled after 18 seconds

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12
Q

What were the conclusions of the Peterson and Peterson trigram experiment?

A

Duration of the short term memory is that 18 seconds

Information was often lost in short term memory unless it can be solidated

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13
Q

Criticisms of Peterson and Peterson trigram experiment

A

The experiment was only done up to 18 seconds and not above 20 - said that in hypothesis

Only done on 24 students - no range

Not life like- isn’t how you use STM - generalisation

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14
Q

What experiment tests the duration of the LTM?

A

Harry Bahrick et al

1975

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15
Q

What were the aims of Harry Bahricks experiment?

A

Wanted to see the duration of the long-term memory

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16
Q

What was the procedure of the long-term memory?

A
  • tested 400 people of various age (17-74) on memory of their class mates
  • a photo recognition test consisted of 50 photos, participants high school yearbook
  • a free recall test participants were asked to list names they could remember of those in their graduating class
17
Q

What were the findings of Harry Bahricks experiment?

A

Photo recognition:

Participants tested within 15 years of graduation, 90% accurate

After 48 years dropped to 70%

Free recall:

60% accurate after 15 years

30% after 48 years

18
Q

What are the conclusions of Harry Bahricks experiment?

A

Identifying the faces was more accurate than free recall

People tested closer to their graduation were more accurate than those tested later on

19
Q

Evaluation of Harry Bahricks experiment?

A

Field experiment - ecological validity

Poor controls - assumed no contact since yearbook

Unclear why recall was reduced after 48 years, duration of LTM?

20
Q

What experiment tests the capacity of the STM?

A

Joseph Jacobs

1887

21
Q

What are the aims of the Joseph Jacobs experiment?

A

How much information can be stored in the STM

22
Q

What is the procedure of the Joseph Jacobs experiment?

A
  • showed a set of digit, increasing by one each time
  • participants had to recall the digits after each showing
  • also did this with letters
23
Q

What were the findings of the Joseph Jacobs experiment?

A

The average span for digits was 9.3 items

The average span for letters was 7.3 items

24
Q

What are the conclusions of the Joseph Jacobs experiment?

A

The STM doesn’t have a very big capacity - can only remember a certain amount of information

25
Q

Evaluation of Joseph Jacobs experiment

A

Some people are going to have a bigger capacity than others - eight year old have average of 6.6, 19 years old have 8.6 digits

George millers findings were different

26
Q

What a George millers experiment?

A

Dots flashed onto a screen, people can count seven dots but not any more. Magic number 7 +/- 2.

People can recall 5 words as well as they can recall 5 letters -chunk things together so we can remember more

27
Q

What did Cowan conclude about STM that could contradict Jacobs?

A

Trough reviewing many studies, STM is likely to be limited to about 4 chunks - STM may not be as extensive as first thought.

Lower end of millers range is more appropriate 7-2=5

28
Q

What is the experiment that tests the capacity of the LTM?

A

There’s isn’t one, it is believed that LTM has infinite capacity.

29
Q

What experiment tests the coding of the STM and LTM?

A

Alan Baddeley

1966

30
Q

What were the aims of Baddeleys experiment?

A

How STM and LTM encode differently (acoustically/semantically)?

31
Q

What was the procedure of Baddeleys experiment?

A

4 lists of words:

  • acoustic similar/dissimilar
  • semantic similar/ dissimilar

2 groups:

  • immediate recall
  • after 20 minutes
32
Q

What did Baddeley find from his experiment?

A

Difficulty remembering acoustically similar words in STM but not LTM

Easy to remember semantically similar words in STM but led to muddled LTMs

Suggests that STM is largely encoded acoustically but LTM is largely encoded semantically

33
Q

Evaluation of Baddeley experiment.

A

Laboratory experiment - less ecological validity (not so meaningful)

Coding may be more complex - visual smell taste. Frost (1972) showed LTM recall was related to visual as well as semantic categories