Stapel, D. A. & Winkielman, P. (1998). Assimilation and contrast as a function of context-target similarity, distinctness, and dimensional relevance. Personality and Social Psychology Bulletin, 24, 634-646

Two studies investigated when context information that is (a) cognitively accessible and (b) relevant to interpretation of an ambiguous target stimulus is used as an interpretation frame (and leads to assimilation) or as a comparison standard (and leads to contrast). Each of the 2 studies studied the influence of the unambiguous context stimulus (Ralph) on judgments of the ambiguous target (Donald).  Exp. 1 investigated the role of two factors for the emergence of contrast and assimilation effects: (i) categorical similarity between the context and the target stimulus and (ii) distinctness of the context stimulus. Exp. 2 kept the above two factors constant and tested the importance of dimensional relevance. Results show that beyond previously known factors of extremity and appropriateness, whether context information instigates assimilative interpretation or contrastive comparison processes may depend on 3 additional factors: (1) categorical context-target similarity, (2) perceived distinctness of the context information, and (3) relevance of the context information to the dimension on which the target will be judged.