Encephalon 19 at Peripersonal Space

Encephalon 19: Emotion vs. Reason (a false dichotomy) and a hidden emotion quote embedded in the text appear at Peripersonal Space. Can you solve the mystery?

Among the included posts are two from Neurophilosophy and (of course) The Phineas Gage Fan Club about the widely-covered Nature paper, Damage to the prefrontal cortex increases utilitarian moral judgements (Koenigs et al., 2007). Can I say anything new about it? [Can I ever finish reading the paper without getting too annoyed? Stay tuned...] Now everyone knows about the "trolley problem" and the "fat man" thought experiments in ethics.

Oh, and don't forget this fun one, "smother for dollars" (Greene et al., 2001):

You are in hospital lounge waiting to visit a sick friend. A young man sitting next to you explains that his father is very ill. The doctors believe that he has a week to live at most. He explains further that his father has a substantial life insurance policy that expires at midnight.

If his father dies before midnight, this young man will receive a very large sum of money. He says that the money would mean a great deal to him and that no good will come from his father's living a few more days. He offers you half a million dollars to go up to his father's room and smother his father with a pillow.

Is it appropriate for you to kill this man's father in order to get money for yourself and this young man?

In unrelated news, the figure below is from a cool article that presents four alternative hypotheses regarding the effects of tool-use on the visuotactile representation of peripersonal space (Fig 1., Holmes et al. 2004).



Holmes NP, Calvert GA, Spence C. (2004). Extending or projecting peripersonal space with tools? Multisensory interactions highlight only the distal and proximal ends of tools. Neurosci Lett. 372:62-7.

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.