U-shaped backward masking functions with nonmetacontrast paradigms

As the interval from the onset of a target letter to the onset of a masking stimulus is increased, target recognition first becomes worse and then improves under some conditions. Previously, these U-shaped functions have been documented only when metacontrast masking paradigms have been used. In the present studies, U-shaped functions were found with nonmetacontrast paradigms. Using a pattern mask, U-shaped functions were found when the target energy was greater than the mask energy. Moreover, a set of parameters was found that produced U-shaped functions when no contours were present within the masking field.