Abstract
We present data to indicate that an abrupt decrement in contrast can elicit the disappearance of stimuli viewed in the periphery of the visual field (Exp. 1). Such elicited disappearance can be produced by luminance changes in stimuli that are darker or lighter than the background. It can also be elicited by contrast decrements due to manipulating the background instead of the target (Exp 2). We also studied the effects of target eccentricity (Exp.3). Under all of the conditions we employed, the proportion of trials upon which disappearance occured increased with the size of the contrast decrement (CD) and eccentricity, but the duration of disappearance remained roughly constant (∼ 2 sec) over these ranges. Since this disappearance phenomenon occurs abruptly and completely, it is somewhat different than the gradual fading effects reported by Troxler (1804). The duration of this CD elicited disappearance is somewhat similar to the duration of Troxler fading, however, so we hypothesize that reappearance in these two phenomena may involve the same mechanisms. This technique provides investigators with a way to abruptly remove stimuli from conscious awareness, and address many issues concerned with implicit visual processing.