The interaction of speed and time in biasing the perception of dynamically changing visual inputs

The perception of the duration of a visual stimulus is a very peculiar sensory experience built without dedicated sensors. Perhaps due to this distinctiveness, duration perception is often influenced by stimulus sensory features such as speed, temporal frequency, or stimulus contrast. For instance, stimulus speed is known to distort temporal judgments, with faster stimuli being perceived as lasting longer compared to static or slow-moving ones. In this study, we explored whether this effect depends on stimulus configuration and persists when salient sensory cues at interval onset and offset are available to solve the temporal task ("filled" vs. "flanked" condition). Additionally, given the strong link between speed and time, we wonder whether stimulus duration can affect speed judgments. To answer these questions, we ran two distinct experiments in which healthy volunteers discriminated either the duration or the speed of noisy incoherent random dot kinematograms whose duration and speed were manipulated orthogonally. The results of both experiments revealed that perceived duration was biased by the stimulus speed, as expected, and that this effect persisted across stimulus configurations. Moreover, we found that the duration of the stimulus influenced the perception of speed, albeit to a lesser degree. These findings emphasize the significance of sensory input integration and the temporal structure of stimuli in shaping both duration and speed perception.