Assimilation and contrast effects in voter projections of party locations: Evidence from Norway, France, and the USA

In the standard Downsian model, voters are assumed to choose parties based on the extent of ideological proximity between the voter’s own position and that of the party. Yet it is also well known that there are rationalization and projection effects such that voters tend to misestimate the policy platforms of candidates or parties to which they are sympathetic by overstating the correspondence between those positions and the voter’s own preferences (see, e.g., Markus & Converse 1979; Granberg & Brent 1980; Granberg & Holmberg 1988; Merrill & Grofman 1999). Here we follow insights in the psychological literature on persuasion (Sherif & Hovland 1961; Parducci & Marshall 1962) by distinguishing between assimilation and contrast effects. Assimilation refers to shortening the perceived ideological distance between oneself and parties one favors; contrast refers to exaggerating the distance to parties for which one does not intend to vote. Using survey data on voter self-placements and party placements on ideological scales for the seven major Norwegian parties, five major French parties, and two major American parties we show that both assimilation and contrast effects are present in each country to a considerable degree. We also investigate the possible effects of randomness in party placement and scale interpretation – effects that can easily be confounded with assimilation but not so easily with contrast.