Collaborative encoding with a new categorization task: a contribution to collaborative memory research.

Collaborative memory research has focused primarily on the effects of collaboration at recall with collaboration during encoding receiving less attention. In the present study, collaboration was investigated both at encoding and at retrieval to determine its effects and possible interactions. The aim was to clarify whether the collaborative inhibition effect depended on whether the encoding was with the same or with a different partner. A total of 320 participants (160 Italian and 160 Spanish undergraduate students) were administered a modified version of the collaborative memory paradigm with a new categorization task of verbal affective stimuli at encoding. Specifically, they were asked to classify 90 printed words into 6 categories, so as to have 15 words in each category and then did two recall tasks. Participants were assigned to one of five possible conditions according to encoding (collaborative, individual) and recall (collaborative with the same partner, with another partner, and individual). Results show a collaborative encoding deficit and the classic collaborative inhibition effect independently of whether the encoding was collaborative or individual and even in a collaborative recall group that showed a degree of recall output organization comparable to that of the individual recall group. These results are not wholly consistent with a retrieval disruption explanation and are discussed according to divided attention during collaborative recall and how it may contribute to the collaborative inhibition effect.