Extending or projecting peripersonal space with tools? Multisensory interactions highlight only the distal and proximal ends of tools
Authors: Gemma A Calvert
Charles Spence
Nicholas P Holmes
Journal: Neuroscience Letters (2004)
Discipline: NEUROSCIENCE & BEHAVIOR
Keywords: tool-use; peripersonal space; visuotactile interactions; brain representation; body
Affiliations: Department of Experimental Psychology, South Parks Road, Oxford, OX13UD, Oxford University, UK.

Abstract:  The effects of tool-use on the brain's representation of the body and of the space surrounding the body ('peripersonal space') has recently been studied within a number of disciplines in cognitive neuroscience, and is also of great interest to philosophers and behavioural ecologists. To date, most experimental findings suggest that tool-use extends the boundary of peripersonal space-visual stimuli presented at the tips of tools interact more with simultaneous tactile stimuli presented at the hands than visual stimuli presented at the same distance, but not associated with the tools. We studied the proposed extension of peripersonal space by tool-use by measuring the effects of three different tool-use tasks on the integration of visual and tactile stimuli at three distances from participants' hands along two hand-held tools. When the tool-use task required using the shafts or the tips of the tools, visuotactile interactions were stronger at the tips of the tools than in the middle of the shaft. When the handles of the tools were used, however, visuotactile interactions were strongest near the hands and decreased with distance along the tools. These results suggest that tools do not simply 'extend' peripersonal space, but that just the tips of tools actively manipulated in extrapersonal space are incorporated into the brain's visuotactile representations of the body and of peripersonal space. 

Retracted: No

PubPeer comments:
 This paper was criticised as part of a self-reflection posted on Twitter on 2nd-3rd April, 2021 (twitter TheHandLab status 1377760796130869248) Criticism: After rejection from multiple high-tier journals (Nat Neurosci, Curr Biol [Rolling on the floor laughing] ), this 1-expt, N=16 paper was enlarged to 3 expts, N=24 each. The paper ( my career...) relies on a 3-way interaction, p=.045. Weak. The 3-way interaction is of a mixed design: within (distance x side) and between (group). In retrospect, since the paper was actually conceived sequentially, experiment-by-experiment, it should probably have been presented and analysed as 3 separate experiments, with a more specific hypothesis for E2 and E3 compared to E1. The critical effect referred to above (differences between sides at different distances, depending on different tasks) was likely stronger than the p-value for the 3-way interaction suggests, but the design and analysis was not optimal to detect this effect. Also (while I don t recall the details!), it is likely that we tried a number of different ways of analysing or presenting the data before settling on the story that we presented. I think that s quite normal when you re not sure what the effect is you re looking for. At worst, perhaps I would see this more as an exploratory or hypothesis-generating paper. ,