Is it time to lay the sleeper effect to rest?

Abstract

The "sleeper effect " has been defined as a delayed increase in the persuasive impact of a communication from a source low in credibility. This effect failed to appear in the present series of seven replications (total N = 656) of a sleeper effect experiment. However, the effectiveness of communications at-tributed to a source high in credibility did significantly decrease with passage of time when subjects were unprepared to counterargue with the communica-tion. On the basis of these results and a retrospective review of related stud-ies, it was concluded that the latter effect, by itself, could account satisfac-torily for previous findings that source credibility effects dissipate or disappear with passage of time. As many undergraduate psychology students have by now learned, the "sleeper effect" is an established phenomenon in the attitude change literature. This effect is said to occur when a communication from a source of low credibility has a greater persuasive impact after some time delay than on original exposure. The communication works, that is, while the audience "sleeps " on it. Descriptions of the sleeper effect may be found in a variety of social psychology texts. Examination of the authors ' bookshelves indicated that approximately 75 % of recent survey texts make explicit reference to the sleeper effect as an established phenomenon. The negative results of seven replications of a sleeper effect experiment to be reported here prom~ted the authors to reexamine the empirical literature on this phenomenon. Remarkably, this retrospective review led to the conclusion that the sleeper effect has never had a truly satisfactory emnirical basis. The origin21 report of a sleeper effect by Hovland, Lumsdaine, and Sheffield (1949) was based on only a subset of the opinion items they