Temporal facilitation and stroboscopic motion*

Luminance of extended-duration adapting field was varied from zero to a level sufficient to reduce brightness of a 5 ms test stimulus to a level just above increment threshold. Increasing the luminance of surrounds or solid adapting fields resulted in increased reaction time. With the perceived-order method, reduction of latency with increasing surround luminance (temporal facilitation) was obtained with a visual comparison stimulus but not with an auditory comparison. It was concluded that perceived motion is a necessary condition for temporal facilitation. This study and earlier studies using moving test stimuli may be explained by a shift from sustained to transient units with increasing adapting luminance.