The effect of cognitive load on time-to-contact estimation across different time structures

Time-to-contact (TTC) estimation is critical for daily activities, assessing when a moving object will reach a location. TTC tasks are used to study motion processing. In the TTC tasks, time structure (T) refers to the ratio of the durations of the motions in two phases: (a) one in which the stimulus is visible before it reaches occlusion point and (b) one in which it is invisible after it reaches occlusion point. The condition of T = 1.0, which indicates that the time spent moving is the same across the two segments, is called an equal time structure; otherwise, it is called an unequal time structure condition (T ≠ 1.0). The present study investigated the effect of cognitive load on TTC estimation across different time structures using a dual-task paradigm across two experiments. Experiment 1 showed that when visual velocity was available, high cognitive load enhanced participants performance in T ≠ 1.0, but had no effect on T = 1.0. Experiment 2, isolating visual velocity information, showed no significant differences in performance across different cognitive loads. These findings indicated that cognitive load could have a differential effect on TTC estimation in relation to visual velocity cues and time structure, offering insights into optimizing cognitive processes associated with time judgments.