The degree of consumer "sophistication" is an important factor in the judicial evaluation of the legal standard of trademark infringement: the likelihood of consumer confusion. Yet although the law in this field is premised on assumptions about consumer psychology, the case law has developed in ignorance of an important body of scholarship devoted to that very subject. This article seeks to remedy this disconnect by drawing on scholarship in the field of consumer psychology to develop a model of consumer cognition. The consumer psychology literature suggests a much richer conception of sophistication than is currently acknowledged by the courts. The case law is dominated by an ad hoc treatment of sophistication that has generated numerous conflicts and inconsistencies in the judicial evaluation of trademark infringement. Our model provides a comprehensive framework for understanding the proper role of consumer sophistication in trademark infringement litigation and for resolving many of the conflicts in the case law.