Abstract
Language acquisition is often said to be a process of mapping words into pre-existing concepts. Some researchers regard this theory as an immediate corollary of the assumption that all problem-solving involves the application of concepts. But in light of basic philosophical objections to the theory of language acquisition, that kind of rationale cannot be very persuasive. To have a reason to accept the theory of language acquisition despite the philosophical objections, we ought to have experimental evidence for the existence of concepts in prelinguistic children. One of the few lines of research that attempts to provide such evidence is the work of Paul Quinn, who claims that looking-time results show that four-month old infants form "category representations". This paper argues that Quinn's results have an alternative explanation. A distinction is drawn between conceptual thought and the perception of comparative similarity relations, and it is argued that Quinn's results can be explained in terms of the latter rather than the former.