Using pictures from hotornot.com, researchers tested men and women's reactions to accepting prize money in the following scheme: they could accept a check for US$15-35 tomorrow, or they could wait and get paid US$50-75 "at a variable point in the future." The students were shown pictures of attractive members of the opposite sex before being made to make a decision.
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.
And that is why commercials work.
