A research has pointed out that the best way to solve a difficult problem is to get away from it for a few minutes or just sleep on it overnight.
Those who consciously struggle with a difficult question are more likely to get the wrong answer, compared with those who put it on the mental backburner, experiments show.
Students were asked to choose the best models from four imaginary makes of car.
Each had 12 different features but two had better road holding and fuel economy. After reading about each car, one group of students was asked to make an instant choice.
Another group carried out a second test, which was designed to occupy their minds for five minutes before making their decision.
Volunteers in the second group were more likely to select the best car, the results showed.
Experts believe this is because their subconscious minds were given the time to weigh up all the pros and cons.
"Unconscious thought produces better decisions than when people decide immediately," the Daily Mail quoted psychologist Maarten Bos, who led the research at Radboud University in the Netherlands, as saying.
"Although in our current experiments participants did not actually sleep on their decision, the benefit of a period of rest is clear.
"It allows us to differentiate between the vital and the irrelevant aspects. When your grandparents advised you to sleep on a decision first, they may have intuitively sensed the benefits of letting it rest to get a clear grasp of one's priorities," Bos added.
The study will be published in a forthcoming edition of the Journal of Consumer Psychology.