Long term memory

Question 1

• Taught himself series of nonsense syllables (DAX, BUP, LOC), until could repeat lists twice in order without errors. Tested retention at various delays. Counted amount of time it took to relearn the lists, using same criterion of 2 perfect recitations. Measured how much faster second learning was than first
• Retention decreases as retention interval increases
• BUT rate of forgetting slows down.
• Basic results have been reproduced many times in years since.

Answer 1

Ebbinghaus 1985

Question 2

4 experiments, examined memory capacity and retrieval speed for pictures and words.

• Memory capacity, as a function of the amount of material presented, follows a general power law with a characteristic component for each task
• Pictorial material shows an overall superiority to verbal material. The capacity of recognition memory for pictures is almost limitless.
• When recognition task is made harder by using more alternative, memory capacity stays constant and superiority of picture is maintained.
• Picture memory also exceeds verbal memory in terms of verbal recall.
• Verbal memory shows a higher retrieval speed, inferred from reaction time measures.

Answer 2

Standing 1973

Question 3

Suggested capacity of LTM constrained by rate of acquisition

Humans can take in max ~100 stimuli per minute
Over 70 year lifetime- theoretical capacity limitation of ~3bn stimuli. But no evidence for this as yet.

Answer 3

Lindaur 1986

Question 4

Evidence that memory is reconstructive:

Eyewitness testimony study. Showed that memory of an event can be interfered with by post-event questioning

45 students, shown short clips, and asked to write an account of the accident they had just seen. Also asked to answer some specific questions. Five conditions in the experiment, the only thing varied was the adjective to do with the speed of the vehicles: smashed/collided/bumped/hit/contacted. Asked to esimate how fast the cars were going when they **** eachother.

Results showed clear effect of adjective- e.g. smashed av esitmate was 41mph, contacted was 32mph.

2 possible explanations:

• distortion in memory of participant
• response-biase factors: participant is not sure of eteh exact speed, so adjusts etimate to fit in wiht expectations of the questioner.

Second experiment: similar proceedure. Three conditions: 50 asked how fast were the cars going when they hit, 50 asked how fast when they smashed, 50 not interrogated about speed. 1 week later, participants returned and without viewing the film again were askes series of questions about the accident- critical question was ‘did you see any broken glass?’. (there was no broken glass). ‘Smashed’ condition were significantly more likely to say yes, compared to hit and control.

L and P explained this with the reconstructive hypothesis- that 2 kinds of information go into a persons memory of an event: the info obtained from percieveing the event, and teh other info supplied after the event. Over time the info from these two sources may be integrated in a way that cannot tell what came from which source.

NB limitation: artificial situation, not how people normally witness events. ALso used all student participants- not representative of the general pop, especially not many tend to be experienced drivers.

Answer 4

Loftus and Palmer 1974