Using 40 college students as subjects, this experiment was conducted to investigate differences in the influence exerted by formative groups and declining groups of the same size. No significant differences between formative and declining groups were found at the behavioural level, especially with respect to conformity rates. However, significant differences were found between the two groups at internal levels, especially with respect to the confidence exhibited in subjects' responses and the evaluation of group opinions. In formative groups, the confidence of conformers in the group increased but non-conformers showed no change. In declining groups, the confidence of non-conformers increased but conformers showed no change. Moreover, only the conformers continued to support group opinions after the groups broke down, evaluating the group opinions highly in private. The results suggested in general that individuals are influenced by group changes and that they select their own responses by anticipating changes likely to occur in the group.
