Duration

Question 1

How do you find out how long your STM lasts?

Answer 1

You have to do a ‘distractor task’

Question 2

Who did research on duration of STM and when?

Answer 2

Peterson and Peterson (1959)

Question 3

Describe the method that Peterson did to research duration of STM

Answer 3

Tested 24 students in 8 trials
On each trial the students were given a consonant syllable (eg. YCG, JWG) to remember
They were then given a 3-digit number which they had to count backwards from until they were told to stop
This backwards counting is to prevent mental rehearsal (distractor task)
On each trial they were told to stop after varying periods of time - 3,6,9,12,15 or 18 seconds (retention interval)

Question 4

What was the average recall after 3 seconds?

Answer 4

About 80%

Question 5

What was the average recall after 18 seconds?

Answer 5

About 3%

Question 6

What did Peterson and Peterson’s findings suggest?

Answer 6

Findings suggested that STM duration may be about 18 seconds, unless we repeat the information over and over (verbal rehearsal)

Question 7

Who researched LTM duration?

Answer 7

Bahrick et al. (1975)

Question 8

Describe the participants involved in the research of LTM duration

Answer 8

392 American participants aged 17-74

Question 9

Describe the two ways recall was tested in Bahrick’s experiment

Answer 9

1. Recognition test: 50 photos from the participants’ high school yearbook
2. Free recall test: participants recalled names of their graduating class with no prompts

Question 10

What were the results of participants tested within 15 years of graduation in Bahrick’s experiment?

Answer 10

Were about 90% accurate in photo recognition and dropped to about 60% in free recall regocnition

Question 11

What were the results of participants tested within 48 years of graduation in Bahrick’s experiment?

Answer 11

Recall declined to about 70% for photo recognition, and dropped to 30% in the free recall recognition

Question 12

Give a strength and a limitation for Peterson/ Bahrick

Answer 12

1. Strengths - Bahrick had high external validity because meaningful memories were investigated (names and faces). When LTM studies were conducted with meaningless pictures (Shepard 1967), recall rates were lower, suggesting Bahrick’s findings reflect a more ‘real’ estimate of the duration of LTM
2. Limitations - Peterson’s stimulus material was artificial (YDW). Recalling consonant syllables does not reflect most everyday memory, meaning this study lacked external validity
   HOWEVER, the study isn’t completely irrelevant as we do need to remember some meaningless material (like some phone numbers)