Grab an object with a tool and change your body: tool-use-dependent changes of body representation for action

Abstract

Along the evolutionary history, humans have reached a high level of sophistication in the way they interact with the environment. One important step in this process has been the introduction of tools, enabling humans to go beyond the boundaries of their physical possibilities. Here, we focus on some "low level" aspects of sensorimotor processing that highlight how tool-use plays a causal role in shaping body representations, an essential plastic feature for efficient motor control during development and skilful tool-use in the adult life. We assess the evidence supporting the hypothesis that tools are incorporated in body representation for action, which is the body schema, by critically reviewing some previous findings and providing new data from on-going work in our laboratory. In particular, we discuss several experiments that reveal the effects of tool-use both on the kinematics of hand movements and the localization of somatosensory stimuli on the body surface, as well as the conditions that are necessary for these effects to be manifested. We suggest that overall these findings speak in favour of genuine tool-use-dependent plasticity of the body representation for the control of action.

Does tool use extend peripersonal space? A review and re-analysis

“…This shift of emphasis from peripersonal space to the body schema brings us full circle to the speculations of Head and Holmes one century ago. I will not discuss this fascinating and closely related topic here, but interested readers should turn to the work of Cardinali et al (2009aCardinali et al ( , 2012. Fig.…”

What a car does to your perception: Distance evaluations differ from within and outside of a car

“…Hand-held tools can influence perception of the body and of near space (e.g., Cardinali, Brozzoli, & Farné, 2009;Maravita & Iriki, 2004;Maravita, Spence, Kennett, & Driver, 2002;Driver & Spence, 1998;Spence, Pavani, Maravita, & Holmes, 2004). Specifically, the perception of one's bodily extensions can be varied (e.g., arm length can be extended) by tool use (Cardinali, Frassinetti et al, 2009;Cardinali et al, 2012). That is, differences in space perception after tool use might be a consequence of a variation in the observer's body perception.…”

Movement paths in operating hand-held tools: tests of distal-shift hypotheses

“…Several recent findings on tool use have strengthened the notion that tools become integrated with the body schema (Berti and Frassinetti 2000;Cardinali et al 2009Cardinali et al , 2012Iriki et al 1996;Maravita and Iriki 2004;Yamamoto and Kitazawa 2001). When the effective part of a tool replaces the hand as the end effector of the segmental chain, movement characteristics of the hand should turn into characteristics of tool movements.…”

“…Although the notion of tools being incorporated into the body schema has been supported repeatedly (Berti and Frassinetti 2000;Cardinali et al 2009Cardinali et al , 2012Iriki et al 1996;Maravita and Iriki 2004;Yamamoto and Kitazawa 2001), this idea has also been challenged by recent observations. For example, it has been argued that instead of being incorporated into the body schema, the use of tools changes the allocation of spatial attention (Holmes et al 2007).…”

“…According to a time-honored notion, the proficiency is based on the incorporation of the tool into the body schema (Head and Holmes 1911). In recent years this notion has been supported by different types of physiological and behavioral data (Berti and Frassinetti 2000;Cardinali et al 2009Cardinali et al , 2012Iriki et al 1996;Maravita and Iriki 2004;Yamamoto and Kitazawa 2001). When the body schema is extended by a hand-held tool, the effective part of the tool replaces the hand as the end effector.…”