The detectability of a brief gap in a pulse of light as a function of its temporal location within the pulse

A signal detection experiment was carried out to test the hypothesis that the detectability of abrief gap of fixed duration in a pulse of light would vary with its temporal location in the pulse. For five of six Os, as the gap occurred later and later in the pulse, gap detectability increased until just prior to the end of the pulse, where a sharp decrease was found. The finding was replicated in a seventh O and the decrease in detectability near the end was found to be attributable to the temporal proximity of the end of the pulse. The results are interpreted in terms of the effects of light adaptation and masking.