Tau and kappa in interception - how perceptual spatiotemporal interrelations affect movements

Same principle, but different computations in representing time and space

Time and space are two intertwined contexts that frame our cognition of the world and have shared mechanisms. A well-known theory on this case is "A Theory of Magnitude (ATOM)" which states that the perception of these two domains shares common mechanisms. However, evidence regarding shared computations of time and space is intermixed. To investigate this issue, we asked human subjects to reproduce time and distance intervals with saccadic eye movements in similarly designed tasks. We applied an observer model to both modalities and found underlying differences in the processing of time and space. While time and space computations are both probabilistic, adding priors to space perception minimally improved model performance, as opposed to time perception which was consistently better explained by Bayesian computations. We also showed that while both measurement and motor variability were smaller in distance than time reproduction, only the motor variability was correlated between them, as both tasks used saccadic eye movements for response. Our results suggest that time and space perception abide by the same algorithm but have different computational properties.

Context modulates the impact of auditory information on visual anticipation

Research on the impact of auditory information on visual anticipation in tennis suggests that the intensity of racket-ball-contact sounds systematically biases estimates of the ball’s speed, thereby influencing anticipatory judgments. Here we examined whether the effect of auditory information on visual anticipation is dependent on the sport-specific context in two separate experiments. In Exp. 1, participants watched short videos of tennis rallies that were occluded at racket-ball-contact. Racket-ball-contact sounds of the final shot were either present or absent. Participants faced different tasks in two counterbalanced blocks: In one block they estimated the ball’s speed; in the other block they indicated the ball’s landing location. Results showed that participants estimated longer ball flight trajectories and higher ball speeds in the sound present condition than in the sound absent condition. To probe whether this effect is dependent on the sport-specific context, Exp. 2 introduced an abstract (i.e., context-free) version of the previous stimuli. Based on the ball locations in the original videos used in Exp. 1, we rendered new videos that displayed only a moving circle against a blank background. Sine tones replaced the original racket-ball contact sounds. Results showed no impact of sound presence on location anticipation judgments. However, similar to Exp. 1, object speeds were judged to be faster when the final sound was present. Together, these findings suggest that the impact of auditory information on anticipation does not seem to be driven by sound alone, but to be moderated by contextual information.