Experiencing someone else’s qualia

05/01/2009 by admin.

It is the time of year again when Edge does its yearly question. This year it is, “what will change everything. What game-changing scientific ideas and developments do you expect to live to see?” Among the replies is one from V.S. Ramachandran. I am never disappointed in what Ramachandran has to say and I intend to have a few postings centered on his essay, Self Awareness: the Last Frontier. The Edge contributions are (here).

As well as self, Ramachandran has an insight into qualia.

“…The qualia problem is well known. Assume I am an intellectually highly advanced, color-blind martian. I study your brain and completely figure out down to every last detail what happens in your brain—all the physico-chemical events—when you see red light of wavelength 600 and say “red”. You know that my scientific description, although complete from my point of view, leaves out something ineffable and essentially non-communicable, namely your actual experience of redness. There is no way you can communicate the ineffable quality of redness to me short of hooking up your brain directly to mine without air waves intervening (Bill Hirstein and I call this the qualia-cable; it will work only if my color blindness is caused by missing receptor pigments in my eye, with brain circuitry for color being intact.) We can define qualia as that aspect of your experience that is left out by me—the color-blind Martian. I believe this problem will never be solved or will turn out (from an empirical standpoint) to be a pseudo-problem. Qualia and so-called “purely physical” events may be like two sides of a Moebius strip that look utterly different from our ant-like perspective but are in reality a single surface…So to understand qualia, we may need to transcend our ant-like view, as Einstein did in a different context. But how to go about it is anybody’s guess.”

One of the examples of the disruption of the normal ‘self’ is:

“A patient with a phantom arm simply watches a student volunteer’s arm being touched. Astonishingly the patient feels the touch in his phantom. The barrier between him and others has been dissolved.”     

Ramachandran discusses motor mirror neurons and then goes on to discuss other types of mirror neurons.

“There are also: “touch mirror neurons” that fire not only when your skin is touched but when you watch someone else touched. This raises an interesting question; how does the neuron know what the stimulus is? Why doesn’t the activity of these neurons lead you to literally experience the touch delivered to another person? There are two answers. First the tactile receptors in your skin tell the other touch neurons in the cortex (the non-mirror neurons) that they are not being touched and this null signal selectively vetos some of the outputs of mirror neurons. This would explain why our amputee experienced touch sensations when he watched our student being touched; the amputation had removed the vetoing. It is a sobering thought that the only barrier between you and others is your skin receptors! … I mention these to emphasize that despite all the pride that your self takes in its individuality and privacy, the only thing that separates you from me is a small subset of neural circuits in your frontal lobes interacting with mirror neurons. Damage these and you “lose your identity”—your sensory system starts blending with those of others. Like the proverbial Mary of philosopher’s thought experiments, you experience their qualia.”

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