1. One of the four logical ways in which perception, memory, or representation can transform an experience that is ostensibly merely reproduced. Addition involves adding one or more elements which were not identifiably part of the original source material. For example, in eyewitness testimony, we might innocently recall a particular observation or event which would normally be part of a similar situation but which did not occur on the particular occasion in question. See also deletion; levelling and sharpening; selective perception; selective recall; substitution; transformation; transposition.
2. In rhetoric, adjectio, one of Quintilian's four types of rhetorical figures of speech involving deviation (mutatio): in this case, the addition of elements.