SOCIAL MEMORY PROCESSES

Studies of social memory support the trite adage, "Two heads are better than one." But there is more to this story. When recalling meaningful materials such as stories, word lists, and criminal acts, groups remember more than individuals. But in the recall of meaningless materials such as nonsense syllables, group and individual recall do not differ. However, even with meaningful materials, collaborative memory typically falls short of performance predicted by combining individual output (Clark and Stephenson, 1989). To determine if social interaction influences group recall, students of social memory have turned to comparisons between collaborative and nominal groups (see Figure 1).

Collaboration in Recall

In 1997, Weldon and Bellinger advocated testing nominal groups. In nominal groups participants actually recall separately, and the sum of their nonoverlapping output is calculated. For example, if Tom, Susan, and Hugh are members of a three-person nominal group and both Tom and Susan recall the word puma, that word would be counted as being recalled only once. The advantage of using nominal groups is that the effect of social interaction on group productivity can be determined; the recall of n persons recalling collaboratively is compared to the recall of n persons recalling individually. From the results of experiments that tested recall in three-person nominal and collaborative groups, Weldon and Bellinger as well as Basden, Basden, Bryner, and Thomas (1997) concluded that nominal groups recall more material than collaborative groups, a phenomenon they label collaborative inhibition. Thus, social interaction hurts rather than helps recall. To rephrase the adage: "Two heads apart are better than two heads together."

There is an interesting addendum to this research. Basden, Henry, and Basden (2001) gave both collaborative and nominal groups a second individual recall test. Understandably, the average recall of collaborating subjects was higher than that of nominal subjects on this final individual test. After all, collaborating subjects have the benefit of hearing the recall of others in their group on the initial recall test. When the nonoverlapping recall of the subjects in former nominal or collaborative groups was examined, former nominal group subjects outperformed former collaborative group subjects. In other words, collaboration enhanced the recall of individual subjects but reduced the output of the group as a whole.

Interpretations of Collaborative Inhibition

Contrary to popular intuition, collaborative inhibition does not result from social loafing. (Social loafing refers to motor tasks such as tug-of-war in which a person working with others exerts less effort than a person working alone.) Weldon, Blair, and Huebsch (2000) tested the effect of motivational variables on collaborative inhibition. When they paid collaborative groups to recall more words, collaborative-group recall still fell short of nominal-group recall. Basden, Basden, Bryner, and Thomas (1997) proposed an alternative interpretation of collaborative inhibition. They argued that individual retrieval strategies are disrupted during collaborative recall. For example, suppose Susan's retrieval strategy involved recalling puma, lion, and tiger, in that order. Hearing Tom recall puma and Hugh recall orange leads Susan toward recalling fruits and away from recalling lion and tiger, which she would have normally retrieved after recalling puma.

Several lines of evidence support the strategy-disruption interpretation of collaborative inhibition. For one, organization as measured by clustering (the tendency to recall exemplars of taxonomic categories together) is greater in the recall protocols of nominal subjects than those of collaborative groups, and forcing groups to organize their recall by category eliminates collaborative inhibition (Basden, Bryner, and Thomas, 1997). Furthermore, providing retrieval cues at the time of the test reduces or eliminates collaborative inhibition, as does having group members study items in the same rather than in different orders (Finlay, Hitch, and Meudell, 2000). Alternative interpretations are that waiting one's turn to recall and/or coordinating one's efforts with others may block production (Weldon, Blair, and Huebsch, 2000) and that the specificity of retrieval cues is greater for individual recall than for collaborative recall—that is, the encoding context originally experienced by the individual is diluted during collaborative tests (Andersson and Rönnberg, 1996).

Errors and Social Contagion

Group recall is usually more complete and more accurate than individual recall when groups discuss the events to which they were exposed and strive to reach consensus before recording their joint recall (e.g., Yarmey and Morris, 1998). When recall is collected without prior discussion and ensuing arrival at consensus, collaborative groups may produce more errors than nominal groups. Basden, Basden, Thomas, and Soupasith (1998) tested false memory in groups by omitting the most common examples (e.g., apple), from lists made up of common taxonomic categories (e.g., fruit.) Collaborative groups falsely recalled more critical omitted items than did nominal groups. Furthermore, members of collaborative groups who had not recalled a given critical item often did so on a subsequent individual-recall test, indicating that memory errors may spread from one group member to another.

Roediger, Meade, and Bergman (2001) studied the spread of memory errors within groups. After briefly studying an everyday scene, such as a bathroom, two undergraduates alternated in recalling objects from that scene. Unbeknownst to the true subject in the experiment, the other undergraduate was a confederate of the experimenter. The confederate recalled a nonpresented critical object—a toothbrush, for example—in the course of recalling objects that were actually present in the scene. On a subsequent individual recall test, true subjects often falsely recalled the toothbrush, the critical object. Roediger and colleagues referred to the spread of false information from person to person as social contagion. In subsequent research, social contagion was induced by an implied presence—a bogus confederate, for example. Social contagion is greater when the presentation is brief, when false information is introduced more than once, and when a live rather than a simulated confederate provides the misinformation.

Characteristics of Group Members

People who are familiar with the memory abilities of others in their group may show less collaborative inhibition than people who are unfamiliar with others in the group. Collaborative inhibition is less evident in dyads composed of friends than in dyads composed of nonfriends (Andersson and Rönnberg, 1996). Johannsen, Andersson, and Rönnberg (2000) found that prospective memory in older couples was influenced by reliance on one another's memory. Couples who reported using transactive memory (Wegner, Giuliano, and Hertel, 1985)—knowledge of their partner's memory—showed less collaborative inhibition than older couples who did not. To illustrate transactive memory, a husband may not attempt to remember proper names that he knows his wife will remember, so he instead concentrates on remembering dates and times. Dixon and Gould (1998) studied story recall in young and old participants (older than sixty-five) tested either individually, in two-person groups, or in four-person groups. Collaboration had similar effects on the recall of younger and older participants. As group size increased, recall increased as much for older as for younger participants. Recall at each group size was greater for younger than for older participants. In a second experiment, Dixon and Gould tested story recall in older and younger married couples. Somewhat surprisingly, older couples did not differ from younger couples. Older couples appear to profit more from transactive memory than do younger couples.

Collaboration in Recognition Tests

In tests of recognition memory, groups outperform individuals. As before, "Two heads are better than one." However, as with recall tests, it is important to know if group members effectively share information. Clark, Hori, Putnam, and Martin (2000) found that both two-and three-person groups produced hits more often than individuals but that collaboration did not reduce false-alarm rates. Clark et al. argued that a recall-to-reject strategy underlies group superiority in hits. When a group member can recall an item's occurrence or the circumstances surrounding the item's occurrence, he/she may convince others that the item was actually presented. According to Clark et al., collaboration facilitates recognition performance beyond levels expected from simple rules such as "majority wins" or "follow the leader." As in collaborative-recall tests, performance on collaborative-recognition tests may be influenced by the responses of others in the group. Schneider and Watkins (1996) found that true subjects who made their recognition choices after false responses were given by the experimenter's confederate often conformed to the confederate's choices.

Collective Memory

As illustrated by collaborative memory of long-married couples, memory for events may be distributed among the members of a group (Wegner et al., 1985). Acquiring a complete account of an event—a collective memory—may require obtaining contributions from all members of the group. To study memory distribution in groups, Weldon (2000) proposed a social-network analysis of collective memory. However, the concept of collective memory goes beyond the idea that memory for events is dispersed among members of a group. Memory both emerges from and supports social interaction (Halbwachs, 1980). For example, the growth of autobiographical memory in children depends upon collaborative recall of parent and child (Farrant and Reese, 2000); researchers have studied collective memories of cultures by obtaining memory reports from people of different nationalities. A full understanding of collective memory may require interdisciplinary efforts.

See also:COLLECTIVE MEMORY

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Barbara H.Basden