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ChangingMinds Blog! > Blog Archive > 29-Jan-10
Friday 29-January-10 Illusory suddennessI went to another great lecture recently at the wonderful RSA. This time there were two neuroscientists and two philosophers duking it out over free will and choice. The keynote was by Professor Patrick Haggard who told the story of the famous Libert experiment. Benjamin Libert conducted a simple but remarkable experiment in 1983 that still fascinates psychologists and neuroscientists. All he did was to ask people to press a big red button at any moment of their choosing. He also had their brains wired up so he could measure the electric potential across the scalp that indicated deeper neural machinations. Libert's remarkable findings was that the brain shows activity about 200ms before we consciously think we have decided to press the button, with the tantalizing implication that our subconscious mind decides before our conscious kicks in. The frightening subsequent conclusion is that it's our subconscious that is driving the bus, and that maybe consciousness is some kind of illusion. Since 1983, scans with more sophisticated fMRI equipment have confirmed the finding, that conscious choice happens after the brain starts moving. It made me wonder about how decisions appear. The language of decision-making implies that choice is a sudden, digital step-function, where we think thoughts and reach logical conclusions. But the brain is not a computer and, as Libert's graphs show, what is actually happening is a varying analogue of electrical potential that, when slowed down, can be experienced as an increasing pressure that leads to a realization and 'decision'. Our experience is limited by our ability to perceive the passage of time, and when we seem to make a sudden choice, it may just be that we cannot perceive a rapid rise in neural potential. It may thus be that the apparent suddenness of choice is illusory. I got to ask a question and queried this point. I know I'd hit the button when they started nodding and an interesting debate ensued, including the whole question of illusion and the irreversibility of physical action. It's nice when you think about something and the idea gets recognized as having some merit. I went home, feeling pleasantly chuffed and still pondering how my subconscious came quickly or slowly to the conclusion about illusory suddenness. |
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Main sections: | Disciplines | Techniques | Principles | Explanations | Theories | |
Other sections: | Blog! | Quotes | Guest articles | Analysis | Books | Help | |
More pages: | Contact | Caveat | About | Students | Webmasters | Awards | Guestbook | Feedback | Sitemap | Changes | |
Settings: | Computer layout | Mobile layout | Small font | Medium font | Large font | Translate | |
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