Monday, December 17, 2007

How brain catalogs info. PageRank-style?

"Human Brain Cloud: a multiplayer word association game that started with a single word ("volcano") and has since taken on a life of its own. Players are given a word, which is culled from the database of previously entered words, and asked to enter the first thing that comes to mind. As people interact with the game it collects data about word associations that can be formed into a giant network (the cloud)."

"Researchers at the University of California recently conducted a study in which they found evidence to suggest that our brains catalog and rate the relevance of information by forming connections between data. The researchers compared the brain's system to Google's PageRank algorithm"Source

" The investigators found that a word’s “Page­Rank” was a good pre­dic­tor of how of­ten it would show up when peo­ple were asked to think of words that start with A, with B, and so on.

When it came pre­dict­ing these re­sults, “Page­Rank” beat two oth­er seem­ingly rea­son­a­ble rank­ing sys­tems: tal­lies of how of­ten words show up in or­di­nary writ­ing; and a sim­ple count of di­rect “links” to a word that does­n’t con­sid­er how many words, in turn, link to those link­ing words.

In the PageR­ank for­mu­la, a page gains “im­por­tance” based on how many oth­er pages link to it. But links from pages that are them­selves “im­por­tant,” con­fer more im­por­tance than those that aren’t. Thus, im­por­tance can be thought of as flow­ing through the Web’s link net­work to­ward the most highly “linked-in” sites.

One ex­plana­t­ion for the new find­ings, wrote Grif­fiths and col­leagues, could be that con­nec­tions among brain cells work si­m­i­larly to Web links. Cells that are tar­gets of many con­nec­tions might be­come more ac­tive than oth­ers, in the same way that highly linked-in web­sites are deemed more im­por­tant." Source

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