A beautiful woman can make a guy irrational -- and now there's science to prove it.

Researchers at McMaster University showed male students pictures of women, some of whom were said to be attractive and some not-so-attractive, as determined by the Hot or Not? Web site.

After seeing a very attractive woman, the men were more likely to make dumb choices.

The Canadian researchers asked the male students to roll dice. If they rolled double digits, they were given a choice of taking $15 to $35 the next day or up to $75 after waiting a while.

The men who saw the attractive women were more likely to take the lesser amount.

NewScientist.com said biologists call choosing immediate rewards to greater ones in the future as "discounting the future."

The researchers said they tried the same test with female students. But there was no lessening of intelligence among the women after looking at hunks. Men also didn't show a change in reaction after seeing pictures of expensive cars.

The researchers said men stop thinking about long-term consequences once they get slightly aroused and see a sexual opportunity.