Have you ever had a solution to a problem pop into your head, seemingly out of the blue? It could have been thanks to unconscious mental processes – and, in future, there might be a way to harness such brain activity.
Aurelio Cortese at the Advanced Telecommunications Research Institute International in Kyoto, Japan, and his colleagues have trained people to learn a simple rule they weren’t consciously aware of, yet subtly influenced their decision-making. “As far as I know, no one has [previously] directly shown that people can be trained to use their unconscious mind,” says Cortese.
The process involved getting 18 people to do a simple visual task while they watched a screen inside a brain scanner. They then had to make decisions that required them to learn an arbitrary rule: that a pattern of unconscious brain activity associated with leftward motion would signal A and rightwards motion would signal B.
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Before the human learning could start, the team trained an algorithm to recognise each participant’s corresponding brain activity for the two types of motion. They spent an hourĚýwatching patches of dots moving either left or right, while their brains were scanned.
After this, the human training began. First, the participants were shown dots moving around randomly and the computer read their brain activity, as before. Even though there was no true direction of motion to perceive, their randomly fluctuating brain activity sometimes matched what it would have been if the dots were actually moving left or right.
Then people were asked to choose between two options, A or B. If they picked the “correct” option – corresponding to their unconscious brain activity signalling left or right, as appropriate – they got a small cash reward, of 30 yen (£0.21).
Although they weren’t told that leftward motion meant A and rightward B, they started to unconsciously learn this rule. Over about 200 trials, they started picking the correct response more often – 54 per cent of the time on the second day on average.
This was only a little higher than if their selections had been down to chance, but “the very fact that they could go above 50 per cent was interesting”, says Cortese. “There’s no way that they can perform above chance if they have no access to the information.”
Some participants scored higher, getting it right about 65 per cent of the time by the end. Cortese thinks they were better at accessing their unconscious mental processes. “With more training, we’d expect the effect size to increase.”
People were also asked to state which way the randomly moving dots were going. Their guesses didn’t correspond to their unconscious brain’s “choice”, showing they weren’t consciously aware of it, says Cortese.
The researchers hope that giving people this kind of training will help in problem-solving or creative activities, where unconscious mental processes play a role – and they are about to start trying this out with artists.
“What we are consciously aware of is a very small part of the space of information being represented in the brain,” says Stephen Fleming at University College London. “This study shows us we can extract some of that information and then use it – it’s pretty compelling.”
Cortese’s group has previously shown that using this kind of brain scanning can reduce people’s fear of certain animalsĚý–Ěý by rewarding them for unconsciously thinking of the animals.
Journal reference:ĚýNature Communications, in press
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