Although rare, Capgras is of interest because understanding it could shed light on the normal processes by which people recognize people. To decide that you are in the presence of your wife, not a stranger who bears an uncanny resemblance to your wife, is to make a personal identity judgement. We make them all the time, usually automatically and effortlessly with people we know well, sometimes with effort when we struggle to place a familiar face encountered in an unusual setting. An understanding of how beliefs about personal identity can go so spectacularly wrong in Capgras and related disorders may afford insight into the ordinary intuitions we rely on to recognize other people and ourselves. (more…)
Posts Tagged ‘neuroscience’
To say that amputees have phantom limbs and whole-bodied people do not is misleading. The so-called ‘phantom’ is the brain’s representation of the body, something everybody has. As neurologist Ronald Melzack put it, “the phantom represents our normal experience of the body.” [Melzack, 1989, p 4]
Amputees differ from other people in that they notice their phantom limbs, while the rest of us do not. They notice them because the corresponding limb of flesh and blood is missing. The difference between representation and reality is what makes the amputee’s phantom salient. The rest of us fail to notice our body phantoms because, when all is well, we cannot distinguish them from our bodies themselves.
I have started to think of the phantom as ‘the brain’s user interface to the body.’ It’s a very good interface, one that might have been designed by a genius like Steve Jobs. It gives your brain exquisite control over your body while remaining utterly transparent to you, the user. Most people go through life without ever realizing that the interface exists.
The interface is so transparent, it only becomes visible at all when there are discrepancies between representation and reality. In this blog, I’ve taken brief looks at two kinds of discrepancy: the phantom limbs which almost all amputees experience, and the rubber-hand illusion which allows an ordinary person to observe her phantom from a new perspective by tricking her brain into shifting the phantom from her real hand to an obviously fake, dummy hand. (more…)
I do not expect a theory of personhood to match all our pre-reflective philosophical intuitions, even if deeply considered and strongly felt (especially if strongly felt!) for two reasons: (1) our best intuitions on this subject are demonstrably unreliable, and (2) billions of otherwise sane and competent people hold beliefs about personal identity which are unsupported by empirical evidence, but to which they have strong emotional attachment. These two facts strongly suggest that there is something wrong with what we are naively inclined to believe about our identity. Hence we should not be surprised to find that a satisfactory solution, when it is found, will at first seem counter-intuitive. (more…)