memory - studies - peterson & peterson 1959

Question 1

Aims

Answer 1

• To test the true duration of STM
• to see if retention of items was affected by
  interference during recall intervals
• second part of their study, they investigated
  whether silent or vocal rehearsal would affect recall of items.

Question 2

sample

Answer 2

• 24 students from an introductory psychology course at Indiana University, USA were selected.
• As part of their course, the students were required to take part in
  research experiments.

Question 3

procedure

Answer 3

• The green light meant that the trial was ready to begin.
• The red light meant to stop counting & recall the trigram (three-letter consonant.)
• Each participant was tested eight times at each of the following six recall intervals: 3s, 6s, 9s, 12s, 15s, 18s
• 2 practice trials to ensure the instructions had been fully
  understood.
• Beginning of each trial, the experimenter would spell out a trigram followed by a number from which the participant had to count backwards in either 3’s or 4’s
  e.g BFP 709, 707
• In half the trials, participants counted backwards in 3’s
• in the other half they counted backwards in 4’s
• Participants counted backwards in time with the ticking of a metronome. This was a task that would minimise rehearsal behaviour between presentation and recall.
• In 2nd experiment, experiment asked participants to do same tasks, but given time to repeat trigram.

Question 4

results

Answer 4

• longer each student had to count backwards, less they’re able to accurately recall the trigam.
• when asked to count backwards after 3s = remembered 80% of trigram
• 18s = less then 10%
  2nd experiment
• extra time increased frequency of recall = able to consolidate info little more
• showed similar decline over time

Question 5

conclusion

Answer 5

• participants unable to rehearse trigrams
• info in our STM fades rapidly, only 10% recalled after 18s
• stm has limited duration
• Only in conditions where the repetition was vocal and controlled did accuracy of recall improve.
• The rate of forgetting from short-term memory depends on the amount of rehearsal undertaken.

Question 6

strengths

Answer 6

• Reliable → Extraneous variables like noise eliminated. Situational variables controlled. Study can be replicated, findings can be checked to make sure they weren’t one-off result.
• Standardized procedure → Fixed timings used - scientific.
• Explains how verbal distraction (interference) affects retention of info.

Question 7

weaknesses

Answer 7

• Lacks mundane realism → recalling trigrams not realistic use of memory.
• Reductionist → biological factors not considered.
• Trigrams may have personal meaning to participant → extraneous variable participant variable.