Two is one too many : dyadic memory collaboration effects on encoding and retrieval of episodes

Sammanfattning: The aim of the present thesis was to investigate how individual memory potential in different tasks is affected by collaboration in social settings. Collaborative group dimensions were also studied: friendship, age, and gender. The principal comparison was between an actual collaborative dyad and the sum of the two individuals' memory potential, i.e., the predicted potential. It was shown, in five studies, that two individuals can not cue each other effectively enough to reach their predicted potential, i.e., negative net effects of collaboration were demonstrated. The widespread feeling of a group superiority is therefore wrong. This effect held true for explicit and episodic memory tasks, but not for semantic and implicit tasks, across materials. Furthermore, collaboration at encoding and retrieval reduced the effectiveness of the cue and the reduced cue effectiveness hypothesis gained support in further tests. Friends, as opposed to non-friends, were shown to possess an ability to reduce the negative net effects of  collaboration. In addition, if the participants (old as opposed to young children) could take their partner's perspective, a reduction of the negative net effects occurred, i.e., the reciprocal understanding hypothesis was supported. It is suggested that young children's lack of perspective-taking ability reduces their possibility to cue each other as effectively as older children. Finally, negative net effects occurred for collaborative dyads regardless of gender constellation. Generally, the data pattern suggests that cognitive theory can explain how individual memory performance is influenced by collaboration. There is (a) a selectivity in the size of the negative net effect with respect to type of memory task and type of dyadic relationship, and (b ), there is a generality of the effect across task materials and gender. Thus, (a) and (b) replicate, extend, and further deepen our understanding of this counter-intuitive phenomenon.