Unlike torts or civil procedure or any area of public law, the laws of promissory exchange only apply to parties who have manifested their assent to be bound. And yet, it is common sense that people sometimes feel bound to exchanges when the law would release them. Norms of promise keeping and reciprocity, interpersonal courtesy, and community reputation have real effects on contract behavior. Although it is perhaps a less exciting claim, it is also the case that the law itself (or, at least, what the parties believe the law to be) affects transactional decisionmaking and parties' commitments to their interpersonal obligations.

This Article presents four new experimental studies of commonsense approaches to contract formation in the hopes of making two primary contributions. The first is to survey intuitions about what the law of formation is. In a world in which the vast majority of contracts are signed without the advice of counsel, most people have to draw their inferences of formation based on their background knowledge and beliefs. We find that the colloquial understanding of contract law is about formalization of an agreement rather than the agreement itself, a finding with implications for how firms may be able to manipulate mismatches between legal rules and ordinary intuitions in consumer markets.