EXPRESS: Hands representation is more fine graded and more pronounced than whole-body only if we are aware of using a motor strategy.

Abstract

Mental representations guide action planning and body execution. While hand representations have been extensively studied, not much is known about differences between hands, feet and whole-body representations. Previous studies tell us about functional and sensory differences between body parts and between parts and whole body, however hands and feet studies also tell us that it matters if we are aware of using motor strategies when we activate body representations, and this has not been compared yet between body parts and between parts and whole body. Sixty participants (M = 26.68, SD = 8.22) took part in an online experiment, including Implicit Association Tests (IAT) where participants are not fully aware of using a motor strategy, and a Mental Motor Chronometry (MMC), a more explicit task requiring awareness of imagining actions. The influence of visual imagery was controlled by administering a Vividness of Visual Imagery (VVI) questionnaire to exclude non-motor-related effects. Results show that when the task requires less awareness to be solved, there are no differences between hands, feet, and whole body. Differences are found when more awareness of body representation and related processes is required, with a more pronounced and finer representation of hands than the whole body. No differences between hands versus feet and whole body versus feet were found. These results highlight the importance of awareness in the representation of body parts and suggest that motor strategies contribute to the differentiation between hand and whole-body representations, a distinction not accounted for by visual imagery differences.