Undergraduate volunteers were divided into Control (n= 18) and Novice Meditators (n = 8). Residents of an American Zen monastery who volunteered as subjects, having 1 year or more experience in meditation, formed a Longer-term Meditation group. All subjects were tested over five trials on the Poggendorff and Müller-Lyer illusions and completed the Taylor Manifest Anxiety Scale and the Beck Depression Inventory. Significant mean differences were found only for algebraic errors on the Poggendorff illusion, and significant decrement in illusion was noted for all subjects. A significant interaction was also found as the Longer-term Meditators showed less initial illusion and less dramatic decrement over five trials than the other groups. Finally, Longer-term Meditators exhibited significantly less anxiety and depression than the other two groups.