Economists have long recognized that physical beauty affects wages, even in occupations where appearance does not seem relevant to job performance. It seems that attractive men and women are paid more than ordinary people for the same work. The question is why.

Two economists, Markus Mobius of Harvard and Tanya Rosenblat of Wesleyan University, recently reported on an experiment that tried to uncover the root causes of the so-called beauty premium.

Their experiment involved a labor market in which employers interviewed applicants for the job of solving mazes. Both the employers and the applicants had been recruited from a pool of students. The applicants first filled out a résumé describing their age, sex, university, graduation date, job experience, extracurricular activities and hobbies.

Then the experimenters gave the applicants a simple maze to solve.

After completing this task, the applicants were asked to estimate how many similar mazes they would be able to solve during their 15-minute employment period. This estimate was interpreted as a measure of the subjects' confidence in their own abilities.