An economics professor and her husband went out to dinner and she observed one of her students drinking alcoholic beverages to excess. The professor knew the economics final exam was scheduled for the next morning. When the professor's husband realized that the student was in his wife's economics class, he described the student's behavior as irrational. The professor disagreed.

Under what conditions is behavior irrational according to the properties of consumer behavior discussed in the chapter? What situations could make the student's behavior rational?