Tuesday, October 18, 2011

The Bayesian Mind

A recent Science News (October 8, 2011) summarized psychological research showing that the human mind thinks in valid probabilities, and specifically, using something like Bayesian statistics.  I cannot tell whether these studies assert that the mind behaves just like the mathematics of Bayesian statistics, whether they simply assert that people change their minds when they experience new things, or a mix of the two.   

It is the first psychological study I have seen in a while providing evidence for a rational mind.  I guess after three decades of research suggesting we are imbeciles who can only prosper under the rule of a benevolent behavioral economist, a study showing a functional human mind is once again a novel finding.

Selected narratives.

People's behavior closely mirrored what Bayesian math predicted, the team reported.

In a way, it's self-evident that humans rely on existing knowledge.  A brain that didn't rely on its experiences would be a pretty pathetic brain.  "You could argue that it would be a little strange if we were bad at it," Geisler says.

If babies act Bayesian, then they may have been born that way.

"As early as we can test, babies are using things that are consistent with probabilistic models," she says.  "Babies are sensitive to the statistics of the environment."

Instead of looking for signs of probabilistic reasoning in young humans, some scientists are looking for signs in other species.  A recent study in owls suggests that aspects of their brains also follow Bayesian rules.

"Biological systems are not accidental," Simoncelli says.  "We believe that evolution shaped them, and shaped them to be good at what they do.  And we have a lot of evidence that that's true."

Sanders, Laura.  October 8, 2011.  "The probabilistic mind."  Science News.

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