This is the kind of comment that is both cheap and, at first glance, insightful ... and just annoying enough for me to defend the opposing point of view:

"Behaving rationally by economic standards" is a fancy way of saying "trying to get what you want". Arguing that someone isn't actually making all the precise cost/benefit calculations before making an "economically rational" action is roughly equivalent to arguing that it's impossible to catch a baseball for anyone who can't solve differential equations in their head.