Balazs Aczel, Aba Szollosi, Bence Palfi, Barnabas Szaszi, Pascal J. Kieslich
Is action execution part of the decision-making process? An investigation of the embodied choice hypothesis

Journal of Experimental Psychology: Learning, Memory, and Cognition, 2018: 44, Heft 6, S. 918–926
ISSN: 0278-7393 (print); 1939-1285 (online)

In this study, we aimed to explore whether action execution is an inherent part of the decision-making process. According to the hypothesis of embodied choice, the decision-making process is bidirectional as action dynamics exert their backward influence on decision processes through changing the cost and value of the potential options. This influence takes place as moving toward one option increases the commitment to and, therefore, the likelihood of choosing that option. This commitment effect can be the result of either (a) the continuous act of getting closer to this option or (b) the increased movement cost associated with changing the movement direction to select a different option. To disentangle the potential influence of these two factors, we developed the Guided Movement Task, a choice task designed to bias participant's computer-mouse movements by constraining the allowed movement space by a corridor. Using this task, we created different conditions in which the participants' mouse cursor, after being guided toward one of the options, either had equal or unequal distances to the choice options. By this manipulation, we could test whether the continuous act of getting closer to an option in itself is sufficient to influence people's decisions–a claim of "strong embodiment." In two experiments, we found that the likelihood of choosing an option only increased when the distances between the two options were unequal after the initial movement but not when they were equal. These results disagree with the hypothesis that action execution is an inherent part of the decision-making process.