The effect of load magnitude on path choice in a decision-making task


We are constantly faced with decisions about how to choose a path when navigating a complex movement environment. When deciding between movement paths that vary in reach distance and walking distance, previous research shows that the path which minimizes reach distance is more likely to be chosen, as reaching is ~11.2x more costly than walking (Rosenbaum et al., 2011; Rosenbaum, 2012; Cappelletto & Lyons, 2018a, 2018b). Our recent work investigates biomechanical factors (joint loading at the trunk and shoulder) during decision-making tasks and provides evidence that these functional movement costs can influence cognitive decision making when choosing between alternative movement strategies in both a two-choice and four-choice model (Cappelletto & Lyons, 2018a, 2018b). It is still unclear how functional costs are incorporated into the planning and execution of a decision-making task with decision factors in multiple domains (e.g. distance and weight). The purpose of this study is to explore how the perceived costs of multiple task variables are prioritized and integrated into action planning. Sixteen participants performed 80 trials of a bucket transfer task that varied as a function of load start location, load magnitude, and terminal target position. Our biomechanical data revealed that participants prioritized decreased reach distance over bearing an increased load, as reflected in decreased joint loading in chosen vs. unchosen paths, which suggests that bottom-up processes are influencing action planning.