June 29, 2005 1:39 PM PDT

Your brain: Search engine, or calculator?

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For years, cognitive theorists have likened the human brain to a computer that completes tasks by breaking down complex problems into a series of small yes/no decisions. A recent study, however, shows that the brain adjusts its thinking as more data arrives.

In a study published online this week in Proceedings of the National Academy of Sciences, Michael Spivey, a psycholinguist and associate professor of psychology at Cornell University, tracked the mouse movements of 42 undergraduate students while working at a computer.

Students heard a word--such as "candy"--and were then shown two pictures. If the pictures were of different sounding objects--such as "candy" and "ziggurat"--the mouse moved in a straight line to the candy and clicked on it. If the words for the pictures sounded similar--"candy" and "candle"--they were slower to click on the correct answer, and the mouse trajectory was more curved. This indicates that, when faced with ambiguity, humans study what limited data they have before clicking.

Under the old metaphor, one would have expected subjects to rush to one solution and then correct the answer if they had chosen wrong.

Interestingly, the whole field of artificial intelligence has moved from a Boolean model, in which systems guide themselves through a series of embedded rules, to a Bayesian model, in which machines guide themselves by studying past experiences. Bayesian probability also underlies search engines.

"In thinking of cognition as working as a biological organism does, on the other hand, you do not have to be in one state or another like a computer, but can have values in between--you can be partially in one state and another, and then eventually gravitate to a unique interpretation, as in finally recognizing a spoken word," Spivey said.


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i don't get it...
doesn't this just sort of go with that annoying thing people always have in their signatures about some study in 'cmbidgare' or something?

if people read words as a whole, instead of by letter, ziggurat would obviously not be candy since it only shares one letter. candle is almost the same word. it requires extra verification like 'a hah, it has an 'le' at the end'

this same study could be done by sitting a 5' person next to a 6'10" person and saying 'which is taller?' and then sitting a 5'8" person next to a 5'9" person and asking the same question.

it's not a painfully obvious answer, and from experience, whenever i have to think about something at a computer, circling the mouse around is the same as looking up and going 'ummm...'

if that's all this study is supposed to prove, that when faced with a more difficult decision, people tend to think more, then i must congratulate these scientists for being able to con someone out of research money...
Posted by Sam Papelbon (242 comments )
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You didn't read the story
Or you'd not have written all that about how many letters are different between the various words. If you'd have read the story you'd have noticed that the words being compared were SPOKEN to the test subjects which therefore means the word is received in parts and not read as a whole.
Posted by aabcdefghij987654321 (1721 comments )
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We are analog, not digital
Without going into too much analysis, I'll take your conclusions as a simple confirmation that, once again, experimental method was unable to make human behavior fit neatly into a "digital" model, all answers being 1's or 0's, "yes" or "no", etc. The physical world is chemical in nature and therefore analog; and we are a product of that environment.
Posted by Razzl (1318 comments )
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