CHANGES IN PREFERENCE

A basic framework for studies of changes in preference is introduced, and four types of changes in preference are identified. Revision by a sentence such as 'A is better than B' means that a preference for A ov er B is acquired. The result of contraction by 'A is better than B' is that the subject no longer holds A to be better than B. In addition a nd subtraction, an alternative is added to, or subtracted from, respec tively, the set of alternatives that are under consideration. Formal m odels of these four types of change are introduced, and they are shown to satisfy plausible postulates for rational changes in preferences.