Memory: Duration, capacity & coding

Question 1

Duration of STM (Peterson & Peterson 1959)

Answer 1

AIM: investigate the duration of the STM when rehearsal is prevented.
METHOD: 24 students recall trigrams after 3 second intervals up to 18 seconds. Then, counted backwards in 3s from 456 to prevent rehearsal.
FINDINGS: 90% recall after 3 seconds in comparison to 2% recall after 18 seconds.

Question 2

Evaluation weakness: low mundane realism

Answer 2

artificial materials

Question 3

Duration of LTM (Bahrick et al 1975)

Answer 3

METHOD: assessing how people could recall the names of the people in their graduating class at high school
FINDINGS: after 48 years, people were still about 70% accurate when it came to putting names to year book faces.
CONCLUSION: we can store in our LTM for potentially a lifetime.

Question 4

Evaluation strength: high external validity

Answer 4

real life materials were used.

Question 5

Capacity of STM (Jacobs 1888)

Answer 5

METHOD: having participants repeat back digit strings (0-9) and letter strings.
FINDINGS: average digit string length was 9.3, average letter string length was 7.3
he concluded it was between 5-9 items

Question 6

Miller (1956)

Answer 6

found that capacity of STM could be increased by chunking information by making links with the information in the LTM

Question 7

Evaluation weakness: poorly controlled

Answer 7

participants may have been distracted whilst doing the task therefore this has low internal validity.

Question 8

Evaluation weakness: Miller over-estimated

Answer 8

the capacity of the STM has actually been found to be 4 chunks.

Question 9

Research on coding: Baddeley (1966)

Answer 9

found that participants were poorer at recalling acoustically similar words in the STM. Whilst they were poorer at recalling semantically similar words in the LTM.

Question 10

Evaluation weakness: low mundane realism

Answer 10

artificial materials used in the form of word lists.