research into duration of memory

Question 1

duration of STM, Peterson and Peterson 1959

Answer 1

• In the experiment participants were given “nonsense trigrams” to remember.
• They were also given a 3-digit number.
• Participants had to recall the trigram after a retention interval of 3, 6, 9, 12, 15 or 18 seconds.
• During the retention interval the ppts had to count backwards from their 3 digit number.

Question 2

Peterson and Peterson findings

Answer 2

-After 3 secs-80% recalled correctly.

-After 18 secs- fewer than 10% recalled correctly.

-STM has a duration of between 18-30 seconds

Question 3

Bahrick et al duration of LTM

Answer 3

-duration of LTM was studied by Bahrick et al (1975) using 392 17-74 year olds

Recall was tested using year books
(1) Photo recognition task
90% accuracy if graduated within 15yrs.
70% accuracy if graduated within 48yrs.
(2) Free recall task.
60% accuracy if graduated within 15yrs.
30% accuracy if graduated within 48yrs.

Question 4

strength-bahrick-high external validity

Answer 4

This is because the researchers investigated meaningful memories (i.e. of people’s names and faces).
When other research has been conducted with meaningless pictures, recall rates were lower.
This suggests that Bahrick et al’s findings reflect a more ‘real’ estimate of the duration of LTM.

Question 5

limitation-artificial stimuli in Peterson’s study

Answer 5

Although not completely irrelevant because we do sometimes try to remember fairly meaningless material (e.g. phone numbers, postcodes).
Recalling trigrams does not reflect most everyday memory activities where what we are trying to remember is meaningful.
This means the study lacked external (ecological) validity as it may not be possible to generalise findings to real life