1 Absorption or incorporation of information or of a substance, or more generally the act or process of making things similar or alike.
2 In the writings of the Swiss psychologist Jean Piaget (1896–1980) and his followers, a form of adaptation (3) in which novel experiences are incorporated into existing psychological structures or processes, as when an infant responds to a new toy that is introduced into its environment by treating it like an already familiar object, interpreting it on the basis of past experience as something to be grasped, shaken, put in the mouth, and so on. See also equilibration. Compare accommodation (2).
3 The influence on a speech sound by one of its neighbours, making the two sounds more alike than they would otherwise be. For example, the plural-forming /s/ is pronounced with a voiced [z] allophone when it follows a voiced consonant, as in the English word dogs, but with a voiceless [s] allophone when it follows a voiceless consonant as in cats. See also wug test.
4 Decreasing the discrepancy between one's own attitude and that of a persuasive source or message. See also assimilation-contrast theory, false-consensus effect. Compare contrast (4).
5 The distortion of a memory through making it similar to already existing memories, a phenomenon that also occurs in serial reproduction and rumour transmission. Compare levelling (1), sharpening.
6 A tendency for the perception of objects or images to take on perceptual characteristics of adjacent objects or images. See colour assimilation. assimilate vb. assimilative adj. [From Latin assimilare to make similar or alike, from ad to + similis like + -ation indicating a process or condition]