Monday, December 29, 2008

Our Unconscious Brain Makes The Best Decisions Possible

Fascinating study about the probabilistic operation of our unconscious.
Pouget's extensive earlier work . . . suggested the human brain is wired naturally to perform [statistical] calculations. . . .

"We've been developing and strengthening this hypothesis for years—how the brain represents probability distributions," says Pouget. "We knew the results of this kind of test fit perfectly with our ideas, but we had to devise a way to see the neurons in action. We wanted to see if, in fact, humans are really good decision makers after all, just not quite so good at doing it consciously. . . . It's weird, but people rarely make optimal decisions when they are told the percentages up front." . . .

Shadlen's team watched the activity of a pair of neurons that normally respond to the sight of things moving to the left or right. For instance, when the test consisted of a few dots moving to the right within the jumble of other random dots, the neuron coding for "rightward movement" would occasionally fire. As the test continued, the neuron would fire more and more frequently until it reached a certain threshold, triggering a flurry of activity in the brain and a response from the subject of "rightward."

Pouget says a probabilistic decision-making system like this has several advantages. The most important is that it allows us to reach a reasonable decision in a reasonable amount of time. If we had to wait until we're 99 percent sure before we make a decision, Pouget says, then we would waste time accumulating data unnecessarily. If we only required a 51 percent certainty, then we might reach a decision before enough data has been collected.


Anonymous said...

There's a lot more to human decision-making than the actions of a pair of neurons. So extrapolating from that to a claim that the unconscious brain makes he best decisions is stretching way too far.

Anonymous said...

Interesting finding. Yet, this is only one facet out of many that account for decision making. If decisions were made only based on immediate input, then decisions would maybe take longer and be only made on simplistic ideals. For humans, decisions are not only made based on current input, but on background knowledge, knowledge that we keep in the back of our minds and in our subconscience. There is much more than the one pair of neurons that account for decisions. I think that is is only part of the larger equation.

RDT said...

I wonder if the greater reach of news media distort the brain's statistics.

My sense is that we over-weight the probability of the types of events that get wide news coverage (plane crashes, terrorist attacks, child abductions), and that the sense that the world is increasing unsafe is partly a result of that.

Anonymous said...

I'm of the same opinion though!

Muazzam Mehmood
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