CONTRAST, ASSIMILATION, AND BASE-RATE EFFECTS - RECONSIDERATION OF THE MANIS-PASKEWITZ JUDGMENT MODEL

We evaluate the Manis-Paskewitz judgment model (Manis, M. & Paskewitz, J. R., 1984; Manis, M., Biernat, M., & Nelson, T. F., 1991) with an e mphasis on what evidence Manis and colleagues provide for contrast and assimilation effects. Contrary to their claims, we suggest that contr ast and assimilation effects are mutually exclusive and that correlati ons alone are uninformative with respect to assessing which has occurr ed. We also argue that the analyses reported by Manis and colleagues d o not speak to whether the experimental contexts they provided their p articipants simultaneously evokedboth assimilative and contrastive ten dencies, the net effect of which were contrastive judgments. We conclu de that the unique component of the Manis-Paskewitz judgment model-the possibility that assimilation and contrast effects may occur simultan eously-has riot been demonstrated and that the analyses reported by Ma nis and colleagues do not constitute an appropriate rest of their clai ms.