In an experiment conducted by Bos while at Nijmegen University, with researchers from Kellogg School of Management, a group of subjects were asked to choose the best out of 12 apartments, and given six rules to abide by (rent must be no more than $2,000 a month, must allow dogs), in making their choice.

Those given four minutes to consider their decision chose apartments that fit with the rules 75% of the time but selected the best apartment just 29% of the time.

Those who deliberated for two minutes and then were distracted for two minutes chose a rule-abiding apartment 44% of the time, but identified the apartment with the best aggregate of attributes 58% of the time.

This may sound deeply mysterious, but most of us are probably familiar with the feeling of having arrived at a decision by unconscious means.