Contrast discrimination and choice reaction times at near-threshold pedestals.

摘要: Choice reaction times (CRTs) to contrast differences were measured and compared with increment thresholds obtained from concurrently psychometric functions at pedestal contrasts in the vicinity of detection threshold. Contrast discrimination had a classical dipper shape. The main finding was that CRTs shorter low but longer higher detection, reflecting behaviour thresholds. Even when equalized for response accuracy, varied similar manner depended on suggests both share common origin. This origin is proposed lie variability sensory effect which determines information accumulation process, turn affects criterion At pedestals, decrease lowers results lower criterion, thereby accelerating times. high increasing signal-dependent noise inflates thus raises slower CRTs.