We present a model of coarse thinking, in which individuals group situations into
categories, and transfer the informational content of a given message from situations in a
category where it is useful to those where it is not. The model explains how
uninformative messages can be persuasive, particularly in low involvement situations,
and how objectively informative messages can be dropped by the persuader without the
audience assuming the worst. The model sheds light on product branding, the structure
of product attributes, and several puzzling aspects of mutual fund advertising.