Optimal Temporal Gap between Two Different Visual Stimuli for Optimal Perception in Perceptual Decision- Making

We encounter different information or stimuli. However, the combination of these stimuli and the quality of their presentation can influence our perception and decision. Despite the importance of these combined stimuli to our judgments and decisions, it is not yet clear how the characteristics of these stimuli affect the decision- making processes. For example, it is not clear whether the time interval between the information we receive can affect the accuracy and speed of decision- making. This study aimed to investigate the effect of the time interval between two different visual stimuli on perceptual decision- making.

According to psychophysical experiments, it was possible to measure the response to perceptual stimuli and compare perceptual choices. In a Random Dot Motion (RDM), the task was displayed to the participants as the primary visual stimulus and a graphic cue as the second visual stimulus, at different intervals, and then the participant's decision accuracy and reaction time to each of these two stimuli were recorded and analyzed.

We found that in RDM (primary stimulus), the accuracy of participants' decisions is not affected by the time interval between the presentation of two stimuli. Instead, the accuracy of the response to the Cue (second visual stimulus) decreases in long time intervals between two stimuli. Interestingly, if two stimuli are presented simultaneously, the decision about each of these stimuli is reasonably accurate; yet, the speed of the decision- making process is slower than when a person encounters two stimuli separated by a time interval.

The human visual system can distinguish visual stimuli that are presented with a short time interval in between; however, in exchange for correctly identifying these stimuli, the speed of decision- making may be slowed down.