Strategies

When a group of people work together to remember an event, the group do appear to recall more than an individual working alone, but do they recall more than the sum of the memories each individual recalls?

Studies have found that "brainstorming" groups actually produce fewer ideas than groups that are groups in name only₁. And in many tasks, from rope-pulling to vigilance tasks, it has been found that people contribute less when they are part of a group than when they are working alone₂.

In this study, two experiments compared the memory performance of nominal and collaborative groups of three, using

• random lists of pictures and words;
• a story (The "War of Ghosts", a supposed folk-tale, long used in psychology labs to demonstrate the errors in people's memories)

It was found that the nominal groups (where individual results were pooled) remembered the best. Collaboration appears to inhibit recall. Such collaborative inhibition was greater with the story than with the list.

References

1. Bouchard, T. J. Jr. & Hare, M. 1970. Size, performance, and potential in brainstorming groups. Journal of Applied Psychology, 54, 51-55.

Diehl, M. & Stroebe, W. 1987. Productivity loss in brainstorming groups: Toward solution of a riddle. Journal of Personality and Social Psychology, 53, 487-509.
Dunnette, M. D., Campbell, J. & Jaastad, K. 1963. The effects of group participation on brainstorming effectiveness for two industrial samples. Journal of Applied Psychology, 47, 30-37.

2. Karau, S.J. & Williams, K.D. 1993. Social loafing: A meta-analytic review and theoretical integration. Journal of Personality and Social Psychology, 65, 681-706.

It has long been known that spacing practice (reviewing learning or practicing a skill at spaced intervals) is far more effective than massed practice (in one heavy session). It is also well-known that people commonly over-estimate the value of massed practice, and tend not to give due recognition to the value of spacing practice, despite the fact that most memory improvement and study programs advise it.

Many learning strategies require extensive training. The advantage of spaced practice is that it does not. Experience with it may also result in better self-appraisal about how well information has been learned.

In this study, a class of 708 students were given instruction sheets on which was written a 7-digit number purporting to be a phone number. The students were instructed to memorize the number and told their recall would be tested later in the term. Half the class were told to memorize the number however they usually would. The other half were told to post the number where they would see it, and look at it once or twice a day for a week. They were told this would be an effective way of learning the number.

A significantly greater number of students from the spaced-practice group remembered the number correctly two weeks later (72.7% compared to 61% of the control group). According to the questions they answered, some 11.6% of the spaced-practice group in fact did all their studying in a single session, and only 46.4% studied the number on 3 or more days. Some 18% of the control group also studied the number on 3 or more days. In other words, being in the spaced-practice group doesn't necessarily mean spaced practice was used, nor does being a member of the control group mean that spaced-practice wasn't used.

Clearly, simple instructions to use spaced practice improve memory, but equally clearly, many people are not necessarily going to follow those instructions, for whatever reason.