Threat affects risk preferences in movement decision making

Abstract

Emotional states such as sadness, anger, and threat have been shown to play a critical role in decision-making processes. Here we addressed the question of whether risk preferences are influenced by postural threat and whether this influence generalizes across motor tasks. We examined risk attitudes in the context of arm-reaching (ARM) and whole-body (WB) leaning movements, expecting that increased postural threat would lead to proportionally similar changes in risk-sensitivity for each motor task. Healthy young adults were shown a series of two-alternative forced-choice lotteries, where they were asked to choose between a riskier lottery and a safer lottery on each trial. Our lotteries consisted of different monetary rewards and target sizes. Subjects performed each choice task at ground level and atop an elevated platform. In the presence of this postural threat, increased physiological arousal was correlated with decreased movement variability. To determine risk-sensitivity, we quantified the frequency with which a subject chose the riskier lottery and fit lottery responses to a choice model based on cumulative prospect theory (CPT). Subjects exhibited idiosyncratic changes in risk-sensitivity between motor tasks and between elevations. However, we found that overweighting of small probabilities increased with postural threat in the WB task, indicating a more cautious, risk-averse strategy is ascribed to the possibility of a fall. Subjects were also more risk-seeking in the WB movements than in ARM at low elevation; this behavior does not seem to derive from consistent distortions in utility or probability representations but may be explained by subjects' inaccurate estimation of their own motor variability. Overall, our findings suggest that implicit threat can modify risk attitudes in the motor domain, and the threat may induce risk-aversion in salient movement tasks.

Explicit Action Switching Interferes with the Context-Specificity of Motor Memories in Older Adults

“…This idea is further supported by findings indicating that aging impacts the integrity of the cerebellum (Luft et al, 1999 ; Raz et al, 2005 ), which regulates the sensitivity to errors driving motor adaptation (Criscimagna-Hemminger et al, 2010 ). Alternatively, older adults are in general risk averse (Albert and Duffy, 2012 ; Tymula et al, 2013 ) and risk-sensitivity has been shown to influence sensorimotor control (Nagengast et al, 2010 ; O'Brien and Ahmed, 2015 ) and motor adaptation (Trent and Ahmed, 2013 ). Thus, it is possible that the aged motor system exploits prior experiences rather than exploring new movements to avoid risks such as falling, which have more serious consequences in old than young populations (Talbot et al, 2005 ; Mitchell et al, 2010 ).…”

Using metabolic energy to quantify the subjective value of physical effort

“…However, there is strong evidence that the subjective valuation of movement-related costs such as time and probability differ from their objective values [2,35]. When considering the subjective value of these costs, models of movement control can better predict movement-related behaviours [36][37][38][39][40][41].…”

On the validity and consistency of misjudgment of stepping ability in young and older adults

“…Consistency in risk-taking behaviour, which could be considered a concept analogue to misjudgment, was studied by O’Brien and Ahmed [ 14 , 15 ]. Subjects that overestimate their ability might be inclined to accept higher risk than under-estimators [ 12 ], who in turn, are more likely to bypass activities to avoid risk exposure out of fear of falling [ 16 ].…”