Unconscious mind influences accuracy of decisions

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The idea that unconscious information can influence our decisions has been an intriguing but controversial idea in psychology.

Information processed unconsciously can influence the accuracy of our decisions without us knowing it, new research has found.

"People tend to think the decisions they make are based on deliberation but there are elements in every type of decision we make that are unconscious -- a lot more than people think," says PhD candidate Alexandra Vlassova, of the University of New South Wales.

"Unconscious information could make your decisions better but it could also make them worse."

The idea that unconscious information can influence our decisions has been an intriguing but controversial idea in psychology, says Vlassova.

In a paper published today in the , she and colleagues report on a study designed to overcome the limitations of previous research into this question.

Participants were given the task of deciding whether a group of grey dots were moving left or right across a computer screen.

"The longer you look at the dots, the more evidence you get and at a certain point you have enough evidence to make your decision," says Vlassova.

"That's quite similar to how we make any type of decision. We accumulate information over time until we have enough to make a decision."

Probing the unconscious

To study how unconscious exposure to the 'decision dots' contributed to accuracy, the researchers presented different images to each of the participants' eyes at the same time.

One eye was shown the grey decision dots and the other eye was shown bright, apparently random-moving coloured dots.

Under these conditions, the coloured dots dominated the participants' conscious mind, while their unconscious mind took in and processed information on the grey decision dots.

"Even though they were not aware that the grey dots are on the screen, they were still able to extract some information from them," says Vlassova.

They then removed the coloured dots and allowed the conscious mind to focus on the grey decision dots which were either randomly moving, moving to the left or moving to the right.

The researchers found that the participants' accuracy was improved by unconscious exposure to the decision dots, but only if the dots were moving in the same direction as those focused on by the conscious mind.

Importantly, the researchers found that they could explain the unconscious decision-making using current mathematical models for conscious decision-making.

Just as accumulated conscious information helps improve decision accuracy, so does accumulated unconscious information -- although less effectively, say the researchers.

"It is not as strong as conscious processing," says Vlassova. "The quality of information being gathered unconsciously is reduced. If it was all conscious information they would be even more accurate"

Also, the researchers found the participants' confidence in their decision was the same regardless of whether they had unconscious information to help them decide.

"They were not aware that they were processing information unconsciously and that it was affecting their decisions," says Vlassova.

By contrast, she says, previous research has shown conscious information we gather prior to deciding increases confidence in our decisions.

Broader implications

Vlassova says if this type of unconscious influence works the same way with far more complex everyday decisions, it could have broad implications.

"For example, when you are driving, a lot of the decisions you make are based on unconscious processing of information," she says.

While the 'power of the unconscious' has often been invoked, Vlassova says there is little evidence to support the idea that subliminal advertising makes people buy products, or that listening to recordings in your sleep can help you learn languages.

"I haven't seen any convincing evidence to support that," she says. "There are definite limits to what we can do with unconscious learning but I think it's a very interesting area."

"This is just the first step and as we understand more we can get a better idea about possible practical implications."