Changes to the movement system may bias decision-making behaviour

What is it about?

Humans often perform movements based on perceptual information arising from objects in the environment. For example, when apple picking or choosing between donuts, one often makes judgements about the quality of the apples or donuts based on the colour of apple's skin or donut's glaze. One then uses a movement to acquire the apple or donut that is judged to be of higher quality. The present investigation was designed to better understand the process of going from decision to action. Specifically, the influence of the action system on such perceptuo-motor decisions was examined. That is, the investigation aimed to answer this specific question: do the characteristics of the actions used to enact these decisions influence the decision-making process itself?

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Photo by Nico Krohn on Unsplash

Photo by Nico Krohn on Unsplash

Why is it important?

When interacting with their environment, humans constantly enact perceptual decisions by performing specific actions. For example, people often choose between two apples based on the color or brightness of the apple’s skin and then grasp the more desirable apple with the left or right hand. Although perceptual features drive decisions, response characteristics may also influence the decision process. The present investigation examined the influence of the action system on perceptuomotor decisions by manipulating the side of space on which the stimulus appeared (a manipulation thought to affect activation levels of the response) and determined if this spatial presentation (and associated response activation) biased choice behavior. The results indicated that participants were biased to make the decision associated with the response that was on the same side of space as the stimulus (the more highly activated response). These findings provide evidence that perceptuomotor decisions are influenced by the action system and that decision making and action systems are highly interconnected.