Neuroscience: Unconscious brain makes best possible decisions

According to a recent Physorg story, the 1970s claim that humans rarely make rational decisions is false:

Pouget analyzed the data from a test performed in the laboratory of Michael Shadlen, a professor of physiology and biophysics at the University of Washington. 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.

I would be interested to know whether this is in part learned behaviour - as I suspect it is. That is, determining how much information is necessary to make a decision is probably partly a matter of experience. It would be interesting to test small children and see.

Neuroscience: When did you really decide to adopt that puppy?

Did you decide to adopt him when you first saw him? When he licked your hand? When you decided to speak to the Humane Society cage attendant? You might be surprised ...

Recent research on making decisions shows that people may actually make a decision ten seconds before they become aware of it.

In "Get Out of Your Own Way" in the Wall Street Journal, Robert Lee Hotz reports,

While inside the brain scanner, the students watched random letters stream across a screen. Whenever they felt the urge, they pressed a button with their right hand or a button with their left hand. Then they marked down the letter that had been on the screen in the instant they had decided to press the button.

Studying the brain behavior leading up to the moment of conscious decision, the researchers identified signals that let them know when the students had decided to move 10 seconds or so before the students knew it themselves. About 70% of the time, the researchers could also predict which button the students would push.

This is very interesting, though not surprising. It provides research support for something that storytellers sense and try to portray - we become aware of a choice after we have already made it.

Shakespeare's villains are especially good at sensing when their victims have already begun to commit to a disastrous course of action - even when they aren't yet conscious of it themselves.

In other research,

Dutch researchers led by psychologist Ap Dijksterhuis at the University of Amsterdam recently found that people struggling to make relatively complicated consumer choices -- which car to buy, apartment to rent or vacation to take -- appeared to make sounder decisions when they were distracted and unable to focus consciously on the problem.

That makes a lot of sense too, because consumer choices are essentially a question of what we think we'd be happy with. The more we think about it, the more complex the problem becomes. I suspect that if the problem involved abstract calculation rather than consumer choice, distraction would not be a benefit.

The puppy is from Purina Canada's site. Learn more about puppy needs there.