Movement characteristics impact decision-making and vice versa

Carsten, Thomas [UCL] Fievez, Fanny [UCL] Duque, Julie [UCL]

Previous studies suggest that humans are capable of coregulating the speed of decisions and movements if promoted by task incentives. It is unclear however whether such behavior is inherent to the process of translating decisional information into movements, beyond posing a valid strategy in some task contexts. Therefore, in a behavioral online study we imposed time constraints to either decision or movement -phases of a sensorimotor task, ensuring that coregulating decisions and movements was not promoted by task incentives. We found that participants indeed moved faster when fast decisions were promoted and decided faster when subsequent movements had to be executed swiftly. Furthermore, inflicting faster movements seems to alter decision-making in a similar fashion as conditions promoting faster decisions: In both fast-decision and fast-movement blocks, decisions relied more strongly on information presented shortly rather than long before movement onset. Taken together, these findings suggest that decisions not only impact movement characteristics, but that properties of movement impact the time and manner with which decisions are made. We interpret these behavioral results in the context of embodied decision-making, whereby shared neural mechanisms may not only enable faster movements but also assist in making decisions in less time.