The central argument of this article is that the initial phases of the consumer decision process have a major effect on product evaluation and choice. Specifically, the need-arousal event and the consequent retrieval of product-related decision constraints from memory substantially influence the ensuing processes of external information search and alternative evaluation. Several hypotheses based on previous experimental research are formulated to capture these influences. Survey data from a large sample of new automobile buyers in New Zealand are used to test the hypotheses. The results suggest that the product-related decision constraints that are activated as a consequence of problem recognition significantly change the remainder of the purchase process. The findings have important implications for understanding how consideration sets are formed. © 2001 John Wiley & Sons, Inc.