Scientists have some remarkable new advice for anyone who is struggling to make a difficult decision: Stop thinking about it.
In a series of studies with shoppers and students, researchers found that people who face a decision with many considerations, such as what house to buy, often do not choose wisely if they spend a lot of time consciously weighing the pros and cons. Instead, the scientists conclude, the best strategy is to gather all of the relevant information -- such as the price, the number of bathrooms, the age of the roof -- and then put the decision out of mind for a while.
Then, when the time comes to decide, go with what feels right. ''It is much better to follow your gut," said Ap Dijksterhuis, a professor of psychology at the University of Amsterdam, who led the research.
For relatively simple decisions, he said, it is better to use the rational approach. But the conscious mind can consider only a few facts at a time. And so with complex decisions, he said, the unconscious appears to do a better job of weighing the factors and arriving at a sound conclusion.
The finding, published today in the journal Science, would have practical implications if borne out by further research.
This is because the new research challenges the conventional approach to making everyday choices that shape so much of life.
But the work is also important, scientists said, because it provides more evidence for a profound reconsideration of the nature of the human psyche.
After Freudian psychology, with its focus on repressed desires, fell out of favor, psychological research largely dismissed the idea that the unconscious played an important role in mental processes. More recently, though, in research popularized in Malcolm Gladwell's bestseller ''Blink," scientists have been finding evidence that the unconscious is not just relevant, but that it is smart.
''There is a bit of a revolution going on in psychology the way that we look at the unconscious," said Timothy Wilson, a professor of psychology at the University of Virginia. ''It is a very different unconscious than Freud imagined."
''Blink" largely focused on snap judgments, such as deciding whether a couple was likely to divorce by watching them for a few moments.
But the Science article looked at what the researchers described as the ''deliberation-without-attention effect."
This was described as the power of the unconscious mind to process information and to mull through possibilities without the person being aware of it.
In one experiment, students were asked to pick one of four cars based on a list of positive and negative attributes. A description of each car's attributes was flashed on a computer screen for eight seconds, according to the paper.
First, the experimenters provided a simple choice, where each car had a list of just four attributes, some positive (''has good mileage") and some negative (''has poor leg room").
Half of the students were asked to think about their choice for four minutes. The other half were asked to do challenging, distracting puzzles for four minutes, preventing them from consciously considering the car options.
In this experiment, the conscious thinkers did a better job than the distracted students of selecting the best car, which was the only one with three positive characteristics; other cars in the experiment had fewer.
Next, the researchers did a similar experiment, but with a much more complicated choice: Each car was described with a list of 12 attributes rather than the four in the prior test.
This time the students who were not allowed to think consciously about the decision did a better job of selecting the car with the most positive attributes.
The results, Dijksterhuis said, underscored flaws in conscious decision-making. A person can pay attention to only a limited amount of information at once, which can lead people to focus on just a few factors and lose the bigger picture. The unconscious is better, he said, at integrating large amounts of information.
Another flaw, he said, is what he called a ''weighing problem." The conscious mind can weigh some factors too heavily, and discount others that are important.
For example, when people buy a house, they tend to put too much emphasis on its size, and not enough on their commute every day, he said. When working through a decision consciously, the mind has a tendency to focus on factors that are easy to articulate -- like the number of square feet -- at the expense of other factors that are hard to put into words.
To see whether what they had found in a lab applied in a more realistic setting, the researchers questioned shoppers. Via surveys, the team determined that people consider more factors when purchasing furniture than when purchasing kitchen accessories.
So they interviewed shoppers leaving a furniture store and a store that sells kitchen accessories. The shoppers were asked how much time they had thought about the product between seeing it and buying it. Later, the researchers contacted all the shoppers to ask how happy they were.
For shoppers who had bought kitchen accessories -- typically a simple choice -- those who had thought about their selection longer were found to be happier. But for the furniture -- a complicated choice -- those who had spent less time consciously considering their selection were said to be happier.
The implication is that for complex choices, once you have done a certain amount of thinking to gather relevant information, further thinking is counterproductive. Instead, busy yourself with other tasks, and let your unconscious work on the problem. (The study did not include data on people who shopped on impulse, spending little or no time gathering information on an item.)
Still, more work will need to be done to rule out other potential explanations for the data, scientists said. For example, it may be that shoppers who spend more time thinking about expensive purchases like furniture could be more critical people, and more apt to perceive problems with their purchases.
Luc Wathieu, an associate professor at the Harvard Business School, said that he is critical of the boom in research that questions the value of rational deliberation, and that he thinks there will turn out to be other explanations for the finding.
Wilson agreed that the research would be controversial, and predicted that it would spark a lot more work in the area. ''Like any great paper," he said, ''it raises more questions than it answers."
Gareth Cook can be reached at email@example.com.