Should you buy that house? Don't sleep on it!

Don't just blink, think.

That's the message of a new study that challenges the wisdom of snap decisions and the power of "unconscious thought."

Spurred by the popularity of Malcolm Gladwell's bestselling book, Blink: The Power of Thinking Without Thinking, and by recent academic studies extolling the virtues of sleeping on decisions to let the unconscious mind sort things out, psychologists at the University of New South Wales and the University of Essex conducted a series of experiments to test how people choose things such as cars and apartments.

Their conclusion? When wrestling with a complex decision, careful, rational thought is still the best way to go.

"Claims about the powers of the unconscious are always appealing and seductive," writes lead author Ben Newell, a senior lecturer at the University of New South Wales in Sydney, Australia, pointing to headlines such as "Dilemma? Don't give it a thought" from The Times of London.

"At best, these sorts of headlines are misleading," Dr. Newell says. "At worst, they're outright dangerous. ... Our research suggests that unconscious thought is more susceptible to irrelevant factors, such as how recently information has been seen rather than how important it is."

Dr. Newell and his co-authors conducted four experiments in which volunteers were asked to choose between a variety of cars or apartments. For example, the apartment variables included space, neighbourhood crime rate, view, friendliness of roommate and cost of rent.

One group made an immediate decision (blink); a second group was distracted with puzzles and then asked to decide (the unconscious thought or sleep on it method); and the third group was directed to think carefully about the different options before making their choice (conscious thought). In general, the conscious thought group picked the car or apartment with the most positive attributes; perhaps more importantly, their choices best matched their values.

For example, people in the conscious thought group who ranked closet space higher than leisure facilities were more likely than those in the blink or sleep on it groups to choose the apartment with the features they said they wanted.

The study is slated for publication in The Quarterly Journal of Experimental Psychology.

Dr. Newell's advice for good decision-making harks back to what Benjamin Franklin called his "moral algebra" - make a list of pros and cons, then assign a weight to each.

Decision makers can also use "the five whys," Dr. Newell says in an interview with the BBC.

This involves asking yourself "why" at least five times before making a choice. For example, if you want to look for a new job, you would ask yourself why. If it's because you're bored at work, why? And so on.

"By going through that process you get to the root of the problem," Dr. Newell says. "And this perhaps provides reasons that you can enter into some kind of decision analysis technique."

Not as easy as blinking, but maybe a sounder strategy for life-altering choices.

(prepared by Rebecca Dube/Globe & Mail)