The visual size is enough to automatically induce the potentiation of grasping behaviours

Abstract

Seeing objects usually grasped with a power or a precision grip (e.g., an apple vs. a cherry) potentiates power-grip and precision-grip responses, respectively. An embodied account suggests that this effect occurs because object conceptual representations would lie on a motor simulation process. A new account, named the size-coding account, argues that this effect could be rather due to an overlapping of size codes used to represent both manipulable objects and response options. In this paper, we investigate whether this potentiation effect could be merely due to a low-level visual feature that favor a size-coding of stimuli: the visual size in which objects are presented. Accordingly, we conducted two experiments in which we presented highly elementary and non-graspable stimuli (i.e., ink spots) either large or small rather than graspable objects. Our results showed that the mere visual size automatically potentiates power- and precision-grip responses that is in line with the size-coding account of the potentiation effect of grasping behaviors. Moreover, these results appeal to improve the methodological control of the size of stimuli especially when researchers try to support the embodied account.