By Renée Grinnell

A distorted perception of reality; unlike delusions, illusions are generally shared by most people, as in a 3D “hidden picture” puzzle.

Example: A breeze stirs the curtains, you see the motion out of the corner of your eye, and you briefly think you see a lurking attacker.

    Last reviewed: By John M. Grohol, Psy.D. on 1 Sep 2011