Humans sacrifice decision-making for action execution when a demanding control of movement is required

Abstract

<jats:p> A growing body of evidence suggests that decision-making and action execution are governed by partly overlapping operating principles. Especially, previous work proposed that a shared decision urgency/movement vigor signal, possibly computed in the basal ganglia, coordinates both deliberation and movement durations in a way that maximizes the reward rate. Recent data support one aspect of this hypothesis, indicating that the urgency level at which a decision is made influences the vigor of the movement produced to express this choice. Here we investigated whether conversely, the motor context in which a movement is executed determines decision speed and accuracy. Twenty human subjects performed a probabilistic decision task in which perceptual choices were expressed by reaching movements toward targets whose size and distance from a starting position varied in distinct blocks of trials. We found strong evidence for an influence of the motor context on most of the subjects' decision policy but contrary to the predictions of the "shared regulation" hypothesis, we observed that slow movements executed in the most demanding motor blocks in terms of accuracy were often preceded by faster and less accurate decisions compared to blocks of trials in which big targets allowed expression of choices with fast and inaccurate movements. These results suggest that decision-making and motor control are not regulated by one unique "invigoration" signal determining both decision urgency and action vigor, but more likely by independent, yet interacting, decision urgency and movement vigor signals. </jats:p>

The Self-Prioritization Effect: Self-referential processing in movement highlights modulation at multiple stages

“…Speiser et al ( 2017 ) found that, under certain conditions, the SAT mechanism in decisional processes can speed up motor-specific preparation (reflected in a faster build-up of EMG-activity), and produce faster movements (but increased overt errors). Indeed, until recently, it was thought that decision urgency and movement vigour may constitute a unique ‘invigoration’ signal, influencing latencies in both decisional and motor processes (see Reynaud et al, 2020 ). In this account, the self-advantage in RT could drive the self-advantage in MT through a shared invigoration signal.…”

“…In this account, the self-advantage in RT could drive the self-advantage in MT through a shared invigoration signal. However, recent work has shown that decisional urgency and movement vigour are actually independent (albeit interacting) signals (Reynaud et al, 2020 ). In line with this, a recent study by Barton et al ( 2020 ) found that self-mug ownership shortened both RT and MT in approach movements and only RT in (participant-body-directed) avoidance movements.…”

“…Following Reynaud et al (2020), and as noted above, the self-advantage in RT and MT must be coordinated by a third factor. One potential candidate is the vmPFC (necessarily through connections with the basal ganglia; Reynaud et al, 2020).…”

“…Following Reynaud et al (2020), and as noted above, the self-advantage in RT and MT must be coordinated by a third factor. One potential candidate is the vmPFC (necessarily through connections with the basal ganglia; Reynaud et al, 2020). It has been proposed that activity in the vmPFC (thought to house a self-representation; Humphreys & Sui, 2016) is rapidly activated by self-relevance and modulates responses by functionally coupling with distinct domainspecific regions associated with different components of the self .…”

“…The potential mechanisms by which a perceptual modulation in Sui et al's (2012) task could influence the movement response are discussed in Desebrock et al (2018). 4 Movement vigour (or vigor;Dudman & Krakauer, 2016;Panigrahi et al, 2015;Reppert et al, 2018;Turner & Desmurget, 2010) refers to the dynamics of motor performance, namely to "the interplay between amplitude, speed, duration or frequency of movements" (Berret et al, 2018, p. 1) and is modulated by an urgency signal that is thought to arise in the basal ganglia (Reynaud et al, 2020;Thura et al, 2014). urgency and movement vigour may constitute a unique 'invigoration' signal, influencing latencies in both decisional and motor processes (see Reynaud et al, 2020).…”