Research On Duration

Question 1

Study for short term memory

Answer 1

Margaret and Lloyd Peterson (1959)

Question 2

Method for Peterson and Peterson

Answer 2

• Tested 24 students in eight trials each
• On each trial, students were given a consonant syllable (eg. YCG) to remember
• Then, they were given a 3 digit number which they had to count backwards from until they were told to stop.
• This backward counting was to prevent mental rehearsal.
• On each trial, they were told to stop after varying periods of time- 3, 6, 9, 12, 15 or 18 seconds (retention interval).

Question 3

Results for Peterson and Peterson

Answer 3

After 3 seconds, average recall was 80%
After 18 seconds, average recall was 3%
Therefore, this shows that STM duration may be about 18 seconds, unless we repeat the information over and over again.

Question 4

Study for Long Term Memory

Answer 4

Harry Bahrick et al. (1975)

Question 5

Method for Harry Bahrick

Answer 5

• Studied 392 American participants aged between 17 and 34
• High school yearbooks were obtained
• recall tested in 2 ways: photo-recognition and free recall

Question 6

Photo-recognition test

Answer 6

50 photos, some from yearbook. Participants who graduation 15 years ago or less, were 90% accurate. Participants who graduated 48 years or more were 70% accurate.

Question 7

Free-recall test

Answer 7

Recalled all the names from their graduating class without any prompts. Participants who graduated 15 years ago or less were 60% accurate. Participants who graduated 48 years ago were 30% accurate.

Question 8

Findings of Bahrick’s study

Answer 8

Suggests that LTM may last up to a lifetime for some material.

Question 9

Evaluation Peterson and Peterson

Answer 9

• stimulus was artificial
• Isn’t completely irrelevant was we do sometimes need to remember meaningless material such as PIN codes or phone numbers
• Recalling consonant syllables does not reflect most everyday memory
• Low external validity

Question 10

Evaluation of Bahrick et al.

Answer 10

• High external validity
• Meaningful memories were investigated.
• When LTM studies were conducted with meaningless pictures (Shepard 1967), recall rates were lower.
• Therefore, Bahrick’s findings were a more ‘real’ estimate of the duration of LTM.