Assimilation and Contrast are Everywhere

Whenever a stimulus is rated, that judgment can be influenced by another stimulus so that the rated stimulus is rated as more similar (assimilation) or less similar (contrast) to the other stimulus. Theories about phenomena referring to assimilation and contrast can be found in several fields of psychology. Still, the respective research is unconnected and has not been integrated. In the present review, we present theories that aim at explaining and predicting assimilation and contrast effects. We observe that theoretical and empirical overlap of the theories and models is surprisingly strong and introduce an ‘overlap-model of assimilation and contrast’ to systematize the plethora of existing theories and phenomena. We discuss potential reasons for similarities between these approaches and suggest that future research should tackle approach assimilation and contrast effects in a more systematic way than has been done in the past.