Movement characteristics impact decision-making and vice versa

Abstract

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 finger tapping movements had to be executed swiftly. These results were further supported by drift diffusion modelling and inspection of psychophysical kernels: Sensorimotor delays related to initiating the finger tapping sequence were shorter in fast-decision as compared to slow-decision blocks. Likewise, the decisional speed-accuracy tradeoff shifted in favor of faster decisions in fast-tapping as compared to slow-tapping blocks. These findings suggest that decisions not only impact movement characteristics, but that properties of movement impact the time taken to decide. We interpret these behavioral results in the context of embodied decision-making, whereby shared neural mechanisms may modulate decisions and movements in a joint fashion.

Dissociable effects of urgency and evidence accumulation during reaching revealed by dynamic multisensory integration

“…Further, the occurrence of changes of mind after the onset of a movement demonstrates that the decision process overlaps with movement execution (Visser et al, 2023). Other studies have shown that speed constraints imposed on decision making can influence the speed of subsequent movements and vice versa (Carsten et al, 2023). In line with such bi-directional influences between decision-making and movement control, Kelly and O’Connell (2013) showed that a centroparietal positivity component in an EEG study scaled both with coherence of a random dot motion stimulus as well as with the reaction time of the subsequent decision.…”

Task goals shape the relationship between decision and movement speed

“…The pacman was presented together with a ghost which will be described in the “Experimental Design” section, as its features depended on the experimental condition the subjects were in. Notably, the pacman animation often ended with a blank screen to cover the minimum 3000 ms period of the movement phase: as such, completing the tapping movement faster never allowed to shorten the trial duration, as in Carsten et al, 2023. Finally, note also that trials in which subjects did not provide a response before Jump -15 did not involve any pacman animation; in this case participants had instead to remain still in front of a blank screen for a period corresponding to the movement phase duration.…”

“…That is, faster decisions are typically followed by quicker movements. Interestingly, the reverse relationship has been observed too: one study in our lab has revealed that when the context requires movements to be performed in a shorter time period, the decisions leading to them arise faster, compared to contexts in which subjects have more time to perform the same movement (Carsten et al, 2023). Altogether, these findings suggest that the urgency signal implemented in decision making models may not solely operate at this restricted level but may shape behavior in a global manner, coregulating the speed of both decisions and movements (Carsten et al, 2023; Thura, 2020).…”

“…Interestingly, the reverse relationship has been observed too: one study in our lab has revealed that when the context requires movements to be performed in a shorter time period, the decisions leading to them arise faster, compared to contexts in which subjects have more time to perform the same movement (Carsten et al, 2023). Altogether, these findings suggest that the urgency signal implemented in decision making models may not solely operate at this restricted level but may shape behavior in a global manner, coregulating the speed of both decisions and movements (Carsten et al, 2023; Thura, 2020). This “coregulation hypothesis” is consistent with the view that the urgency signal serves to maximize reward rate, as in most situations a speeding up of both decision and movement will shorten the time required to obtain a reward (Shadmehr et al, 2019).…”

“…The “coregulation hypothesis” has received systematic support from studies investigating the impact of decision urgency on movement speed (Carsten et al, 2023;Thura et al, 2014; Thura, 2020). By contrast, studies that have addressed this relationship inversely, by looking at the impact of movement speed on the pattern of decision speed, have reported mixed findings (Carsten et al, 2023; Kita et al,2023; Reynaud et al, 2020; Saleri Lunazzi et al, 2021). As mentioned above, we recently observed changes in decision speed in relation to context-dependent adjustments in movement speed that are consistent with the coregulation hypothesis (Carsten et al, 2023).…”