Psychology

Memory Unit 1

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  • Created by: jayde
  • Created on: 02-06-10 15:19

Cognitive Approach- Milner et Al (1957)

Case study of HM

HM was a patient with epilepsy. His seizures were based in a brain structurs called hippocampus. In 1953 doctors deicded to remove part of brain round this area.

Results

Operation reduced his epilepsy, but he had memory loss after it. He could still form short term memories but was unable to frm new long term memories. For exmple he could read something over and over without realising he had read it before. He moved house and had difficulty recalling new route to his house. He could still talk and show previous skills. From tests they found HM's episodic memory (past events) and semantic memory (knowledge e.g word meaings) as affected more than his procedural memory (previous skills)

1 of 3

Short term Memory- Peterson and Peterson (1959)

Wanted to find out how long items would remain in STM without rehaersal.

Method

Presented ppts with a nonsense trigram (three random consonants e.g CXV) they were then asked to recall them after 3,6,9,12,15 or 18 seconds. During this pause they were asked to count backwards in threes from a given number. This ws an 'interference task' prevented them from repeating letters to themselves.

Results

After 3 seconds, participants could recall about 80% of trigrams correctly.And after 18 seconds only 10% could be rcalled correctly.

Conclusion

When rehearsal is prevented, very little can stay in STM for longer than 18 secs approx.

Evaluation

  • +
  • Results are likely to be reliable- as its lab experiment where variables can be lightly controled.
  • -
  • Nonsense trigrams are artificial so the study lacks ecological validity.
  • Meaningful or 'real life' memories may last longerin STM.
  • Only one type of stimulus was used- the duration of STM may depend on the type of stimulus.
  • Each ppt saw many diffrent trigrams. This could lead to confusion, meaning first trigram was only reaistic trial.
2 of 3

Short term Memory- Peterson and Peterson (1959)

Wanted to find out how long items would remain in STM without rehaersal.

Method

Presented ppts with a nonsense trigram (three random consonants e.g CXV) they were then asked to recall them after 3,6,9,12,15 or 18 seconds. During this pause they were asked to count backwards in threes from a given number. This ws an 'interference task' prevented them from repeating letters to themselves.

Results

After 3 seconds, participants could recall about 80% of trigrams correctly.And after 18 seconds only 10% could be rcalled correctly.

Conclusion

When rehearsal is prevented, very little can stay in STM for longer than 18 secs approx.

Evaluation

  • +
  • Results are likely to be reliable- as its lab experiment where variables can be lightly controled.
  • -
  • Nonsense trigrams are artificial so the study lacks ecological validity.
  • Meaningful or 'real life' memories may last longerin STM.
  • Only one type of stimulus was used- the duration of STM may depend on the type of stimulus.
  • Each ppt saw many diffrent trigrams. This could lead to confusion, meaning first trigram was only reaistic trial.Wanted to find out how long items would remain in STM without rehearsal.
3 of 3

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