The effect of predictive visual stimuli on perceived location of auditory targets: Kinematic evidence


Previous research showed that visual information is integrated into the movement plan when reaching to a sound target. Movement planning and execution were negatively impacted, even in the presence of a relevant visual stimulus. The present experiment examined if the voluntary allocation of attention alters the degree to which a secondary stimulus is integrated with the primary stimulus during a goal-directed reaching task. Twenty-two adult participants were assigned to either the Told(T) or Not-Told(NT) condition and asked to reach to the perceived location of a 200ms burst of white noise. Two sound targets located in right and left hemispace were paired with a 200ms light that was presented at the same location on 80% of trials. Participants in the T condition were explicitly aware of the relationship while those in the NT were not. Movement trajectories were recorded using Optotrak 3D Investigator at 300Hz. RT analysis revealed no significant differences between T and NT conditions. Greater spatial variability was observed at peak acceleration in the primary axis when participants were NT compared to being T, but was reduced by movement endpoint compared to the latter. Comparing congruent and incongruent trials, participants exhibited increased variability in the x-axis that was reduced by movement endpoint. The findings indicate participants adopted different movement control strategies based on the amount of information available for accurate limb movement. Precisely, additional information about the probability of the auditory target influenced the strategies adopted by the participants when reaching to the perceived location of auditory targets.

Acknowledgments: Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC), Research Manitoba, and the Canadian Foundation for Innovation