Journal of Personality and Social Psychology 1988, Vol. 54, No. 2,203-218 Copyright 1988 by the American Psychological Association, Inc. 0022-3J14/88/J00.75 In Search of Reliable Persuasion Effects: III. The Sleeper Effect is Dead. Long Live the Sleeper Effect. Anthony R. Pratkanis University of California Michael R. Leippe Adelphi University Anthony G. Greenwald University of Washington Michael H. Baumgardner Burke Marketing Services Inc. Cincinnati, Ohio The sleeper effect in persuasion is a delayed increase in the impact of a message that is accompanied by a discounting cue. Despite a long history, the sleeper effect has been notoriously difficult to obtain or to replicate, with the exception of a pair of studies by Cruder et al. (1978). We conducted a series of 16 computer-controlled experiments and a replication of the Cruder et al. study to demonstrate that a sleeper effect can be obtained reliably when subjects (a) note the important arguments in a message, (b) receive a discounting cue after the message, and (c) rate the trustworthiness of the message communicator immediately after receiving the discounting cue. These operations are sufficiently different from those used in earlier studies to justify a new differential decay interpreta- tion of the sleeper effect, in place of the dissociation hypothesis favored by most previous sleeper effect researchers. According to the differential decay interpretation, a sleeper effect occurs when message and discounting cue have opposite and near-equal immediate impacts that are not well- integrated in memory. The effect occurs, then, if the impact of the discounting cue decays faster than that of the message. A sleeper effect in persuasion is a delayed increase in the im- pact of a persuasive message. The term was first used by Hov- land, Lumsdaine, and Sheffield (1949) to describe opinion change produced by the U.S. Army's Why We Fight films used during World War II. As a pattern of data, the sleeper effect is opposite to the typical finding that experimentally induced opinion change dissipates over time (Cook & Flay, 1978). As such, the sleeper effect is an "interesting quirk" that has at- tracted much research and textbook attention. Early in its history, the sleeper effect became identified with the dissociation hypothesis and was denned as a delayed in- crease in persuasive impact that occurs as a result of a persua- sive message accompanied by a discounting cue. Close scrutiny of previous sleeper effect research, however, reveals that much This research was supported by National Science Foundation grants SOC 74-13436, BNS76-11175, BNS 82-17006, and National Institute of Mental Health grant MH 32317, all entitled Research in Persuasive Communication. The research was conducted while all authors were at Ohio State University. The authors thank Mahzarin R. Banaji. Susan L. Schechtman, and Scott Teagarden for assistance in collecting data, Charles Cruder for supplying the materials used in the Cruder et al. (1978) study, Shelly Chaiken, Alice H. Eagly, William J. McGuire, and Richard E. Petty for the use of their persuasive messages, and Steven J. Breckler, Mary Brickner, Mitzi Johnson, David L. Ronis, and Marlene E. Turner for comments on a preliminary draft of this paper. Correspondence concerning this article should be addressed to An- thony R. Pratkanis, Board of Psychology, University of California, Santa Cruz, California 95064. of the evidence for a sleeper effect is unsatisfactory and that the effect is difficult to obtain. The goals of the research presented in this article are, first, to specify empirical operations capable of producing a reliable sleeper effect and, secondly, to describe the sleeper effect in theoretical terms that can guide a search for other conceptually similar and effective operations. Nomenclature Figure 1 displays four data patterns that appear frequently in a sleeper effect research. Each is a persistence-of-persuasion function: a relation between measurement delay following a persuasive communication and opinion. The most common persistence function is the decay of persuasion that typically oc- curs for effective communications (Figure 1A). The sleeper effect pattern is one that starts at or above the preopinion level and shows an increase in persuasion with measurement delay (Figure IB). A boomerang effect occurs when a communication initially changes opinion in an opposite-from-intended direc- tion. The nonpersisting boomerang effect (Figure 1C), although taking the form of a delayed increase in agreement with the communication, is conceptually more similar to decay of (nega- tive) persuasion than it is to the sleeper effect. The relative sleeper effect (Figure ID; Cook, 1971; Cook, Cruder, Hennigan, & Hay, 1979) involves two juxtaposed per- sistence-of-persuasion functions, one showing decay of persua- sion and the other showing both less initial impact and less (or no) decay. In a typical experiment that produces the relative sleeper effect pattern, decay of persuasion occurs for a commu- nication from a highly credible source, whereas a lower and 203