A computer‐mediated communication system (CMCS) was used to explore the effects of de‐individuation on group polarization. Reicher (1984) argued that de‐individuating members of a group should increase the salience of group identity and hence normative behaviour, while de‐individuating subjects treated as individuals should have the reverse effect. We extended this idea to the group polarization paradigm and in addition independently manipulated group salience and de‐individuation, which were confounded factors in Reicher's study. It was reasoned that the visual anonymity created by isolating discussants in separate rooms would be de‐individuating compared to seating them together in the same room. At the same time either the subject's group or individual identity was made salient. A computer‐mediated communication system provided text‐based communication for discussants in all four conditions. Assuming that group polarization reflects conformity to a group norm (Turner, Hogg, Oakes, Reicher & Wetherell, 1987), we predicted an interaction between the de‐individuation and group salience factors, such that greatest polarization in the direction of a pre‐established group norm would be obtained in the de‐individuated—group condition and least in the de‐individuated—individual condition. This prediction was confirmed. Explanations of the findings in terms of Reicher's earlier study and in terms of self‐attention processes are considered within the general framework of social identity theory. Finally, the relevance of this research to the realm of human communication via computer networks is evaluated. 1990 The British Psychological Society
