Abstract When two or more stimuli are presented to describe a hypothetical person, people often report their impression of the person as if they are averaging these stimuli. The weighted averaging model of impression formation (N. Anderson, 1981) fits empirical data; however, it has been criticized for its lack of psychological plausibility. A psychological process model of the averaging phenomenon is presented, which combines the heteroassociative matrix memory model (Anderson, 1972) and a distributed representational adaptation of the variable perspective model (Upshaw, 1962). The model proposed here is consistent with the weighted averaging model and can explain empirical findings about order effects in impression formation that are inconsistent with the anchoring-adjustment model (Hastie, 1988). The model also predicts time variability and response dependency, which are not predicted by existing models of prototype production (a task similar to impression formation). The results of an experiment are reported in support of the present model.