The problem of 'intentional' signaling is of interest to evolutionary biologists concerned with animal conflicts and to cognitive ethologists attempting to determine whether nonhuman animals exhibit evidence of complex mental states. Recent theoretical and empirical advances in this area have led to a number of important insights concerning the nature of competitive social interactions. Specifically, and in contrast to earlier claims, individuals involved in social conflicts often produce displays that predict their-subsequent behavior, and such predictive displays occur even when repeated social interactions are infrequent. Moreover, studies on a taxonomically diverse set of organisms show that deception, in the form of withholding information, is prevalent. Deception through concealment of information may be widespread because it is more difficult to detect than active falsification of information.