Both male and female students at McMaster University were shown pictures of the opposite sex of varying attractiveness taken from the website 'Hot or Not'. The 209 students were then offered the chance to win a reward. They could either accept a cheque for between $15 and $35 tomorrow or one for $50-$75 at a variable point in the future.
Wilson and Daly found that male students shown the pictures of averagely attractive women showed exponential discounting of the future value of the reward. This indicated that they had made a rational decision. When male students were shown pictures of pretty women, they discounted the future value of the reward in an "irrational" way - they would opt for the smaller amount of money available the next day rather than wait for a much bigger reward.
Women, by contrast, made equally rational decisions whether they had been shown pictures of handsome men or those of average attractiveness.