The speed prior account: A new theory to explain multiple phenomena regarding dynamic information.

Our perception of moving stimuli is prone to systematic biases. Different biases, for example concerning the perceived speed, or spatial location, of a dynamic, moving stimulus, have consistently been reported in the literature. Different lines of experimental research, together with different theoretical explanations, have emerged analyzing and discussing these biases separately. In the present study, we propose a new theoretical account to unite various effects relating to dynamic/moving stimuli: The speed prior account. The perceived location of a stimulus is suggested to reflect the combination of the sensory input, which is associated with uncertainty, and a prior expectation concerning stimulus speed. Discrepancies between the prior speed expectation and the actual speed of a stimulus then result in a distortion of perceived stimulus speed, leading to the various perceptual biases that have been observed. In the present study, we demonstrate that this new theory can already account for robust data patterns currently unexplained in the literature, while we additionally directly test the predictions of the new speed prior account across four experiments. The influence of stimulus speed was manipulated in two visual as well as two tactile studies (all N = 30). The results reveal a clear data pattern, consistent with the speed prior account, as perceived onset and offset location reveal strong interdependencies. The implications and possible future questions for the perception of moving stimuli, in particular, and dynamic information, more generally, are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).