Capacity & Duration of STM & LTM

What was Miller’s estimate of the capacity of short-term memory?

• 5-9

• Average of 7

Explain what evidence Miller based his claim on

• Review of digit span experiments

• Observations of everyday life

Explain how the capacity of short term memory can be extended

• through chunking information

• Into more meaningful groupings of information

What is the serial position effect?

People tend to recall items from the:

• Beginning of the list (primacy effect)

• End of the list (Recency effect)

• Serial Position effect = primacy effect + recency effect

• U shaped curve

Outline the case study of Clive Wearing

• Virus destroyed large parts of hippocampus in his brain

• Has virtually no memories of events since damage

• STM is largely normal - hold information for at least 7 seconds

• Memories pre damage are intact and frozen in time

• STM functions but doesn’t transfer to LTM

Explain the procedure of the Peterson’s experiment on the duration of short-term memory (3)

• Trigrams shown to participant

• Participant counts backwards in 3s from 100

• Tested at 1 interval of 3 seconds during countdown

What did Peterson’s claim about the duration of STM from this experiment? (1)

It was around 18 seconds

Explain the procedure of Bahrick’s study of the duration of long term memory (4)

• High School Graduates

• Tested after 15 & 48 years on recall of class mates:

• Tested by free recall/

• /cued recall (using photos)

Outline the main results of Bahrick’s study of the duration of LTM (4)

• Free Recall: 60% (15 years), 30% (48 years)

• Recognition: 90% (15 years), 70% (48 years)

Explain what conclusions can be drawn from Bahrick’s study of the duration of LTM (2)

• Long-term memories can remain stored for a very long time

• Cues increase recall from LTM