"Investigators asked college students to choose foods from menus that differed in only one feature; one menu offered a salad and the other did not. The point? To find out whether the presence of a salad on the menu influenced what else the students ate. It did. The students choose French fries more often from the menu with the salad."
Saturday, 18 April 2009
Irrationality, salad and chips - failure of the independence axiom
One of the basic tenets of our approach in economics is that the mere presence of an extra possible choice in the options available to a rational consumer should not affect the decision taken, as long as the consumer does not choose the extra choice itself. This is a version of the "independence of irrelevant alternatives" assumption that crops up in pretty much all rationalchoice theories. However, it seems that the mere presence of a salad on a menu, even if not chosen, makes diners more likely to opt for chips. See this article.