Monday, April 15, 2013

A horse in your head

You want to make a chair. What are you going to do? According to Plato we have innate ideas in our heads that show how the objects in the world look like. These ideas are more like blueprints or templates than the abstract conceptions that nowadays are called “ideas”. Therefore, they are also called “forms”. What you do then when you want to make a chair is that you call up the form “chair” from your memory and make a wooden (or stone etc.) copy of it, of course with your personal variations or with the variations demanded by your client. But does it really work that way?
Yukiyasu Kamitani and his colleagues of the ATR Computational Neuroscience Laboratory in Kyoto, Japan, asked three volunteers to have a nap in an fMRI brain scanner. While the test subjects were sleeping the scanner registered the activities of their visual cortices. When they started to dream, the volunteers were wakened and asked to tell what they dreamed about. From these dreams the researchers choose some simple objects like house, table, man, and so on. In the second part of the experiment the volunteers were shown pictures of these same simple objects, while the brain scanner registered again their brain activities. Then the volunteers had again to sleep in the fMRI scanner. When they had woken up, the researchers compared the scans made in this third phase of the experiment with the results of phase one and two and in about two third of the cases they could read correctly what the volunteers had been dreaming about. What the researchers saw was still rather abstract and when they concluded correctly, for instance, that a volunteer had been dreaming about a man, they couldn’t say whether this man was his neighbour or the Japanese Prime Minister or whoever, but anyway a first step has been done on the path of dream reading.
What does this mean? Paraphrasing moon walker Neil Armstrong, we can say that it’s one small step for the researchers but a giant leap for dream research. It will help us understand what dreams really are: Just epiphenomena of brain activity or ways of storing our recent experiences? Steven Scholte, neuroscientist at the University of Amsterdam, thinks that the implications are even wider: “At the moment there is a wide gap in our understanding how visual perception is related to concepts like ‘chair’ or ‘horse’. This kind of research will redefine what semantic knowledge is and how the external world is enciphered in the brain”. And this has philosophical implications, so he goes on, for “unless when you believe in ghosts, this representation in the brain is also what the external word is … When talking about a horse what do we exactly mean by ‘horseness’? What do we mean by ‘chairness’? On a fundamental level this is about what the world is and how we experience the world”.
Actually this fits well what Plato thought, for maybe ideas or forms are not innate, as he believed, it seems that Plato rightly supposed that you need to have a horse in your head in order to know that what you see out there really is a horse.
Source: De Volkskrant, April 6, 2013: Science Supplement, p. V5.

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