Colloquium Cognitive Systems

Getting to grips with human tool use: a sensorimotor-control perspective

Dr. Simon Watt (School of Psychology and Sport Science, Bangor University, Wales, UK)

Abstract:  The ability to use complex handheld tools is a defining human characteristic. The modal account of this ability is that tools are incorporated into the body schema, and thereby controlled ‘as-if they are a body part’. Although widely assumed, this account is essentially descriptive, and what it means for the sensorimotor control mechanisms that underlie tool use is arguably under-specified and understudied. Historically, psychological research has typically explored corollaries of tool use (spatial attention, space representation) rather than sensorimotor control per se. Recent work uses aftereffects to probe the specific idea that tools alter the internal representation of the hand/arm (consistent with them being internalised by altering the body schema), but there is a lack of consensus regarding the outcomes of this work. We take a different approach to understanding sensorimotor control of tools, based on a functional description of the requirements for controlling them as body parts. We first ask, what are the signatures of normal hand control (i.e. what mechanisms/processes does controlling a body part imply?)? We next ask what additional processes are required for tools to be controlled equivalently. Then, we examine empirically whether such processes are evident during tool use. Depending on the tools’ specific geometric properties, we sometimes find that tool use rapidly resembles control-as-a-body-part, but we also find surprising ‘failures’. Understanding what drives these differences should ultimately reveal fundamental principles of human tool use, which can in turn inform development of a wide range of devices, including surgical robots, VR systems, and prosthetic limbs.

About: CV:  Simon earned a PhD in Psychology at the University of Surrey, supervised by Mark Bradshaw. He then worked as a postdoctoral researcher at UC Berkeley, working with Marty Banks, before joining the faculty at Bangor in 2004. Simon is a Senior Lecturer in the Department of Psychology in the School of Psychology and Sport Science. He is Director of the Cognitive Neuroscience Institute — a research group in the school. His research comprises a range of basic studies on how we see and use our hands in 3d space. This includes research on tool use, multisensory integration (of vision and touch), reaching and grasping, and 3d vision. A common thread (beyond topic areas) is that Simon's research aims to integrate fundamental science with practical use (an approach known as Pasteur's Quadrant). Much of his work on sensorimotor control aims to inform development of devices such as prosthetic hands, while his work on 3d vision aims to informs development of stereoscopic displays and VR technology.