Sleeper Effect

The Sleeper Effect, first identified by the psychologist Carl I. Hovland in the middle of the 20th century, refers to the short-term and long-term effects of communications depending on the communicator's image.

In the 1940s, Hovland studied attitude changes on the basis of learning theory or reinforcement theory approach. Researchers Hoveland, Lumsdaine, and Sheffield examined the impact of the film The Battle of Britain (the fourth film of the series “Why We Fight” that was showed to recruits of the U.S. army) on U.S. soldiers' attitudes. They found that some changes in attitude in the direction of the communicator's position were more pronounced after several weeks than immediately after the confrontation with the film. This phenomenon they described as the Sleeper Effect.

One hypothesis that Hovland and his colleagues advanced for this result was that individuals may be suspicious of the communicator's motives, initially discount his position, and thus may show little or no change in opinion. However, with the passage of time one may remember what was communicated and not who communicated it and then may be more inclined to accept the position of the communicator.

In other experiments in the early 1950s, Hovland and Weiss wanted to verify the Sleeper Effect under controlled conditions. They examined the differences in the retention and the acquisition of identical messages when being attributed to a “trustworthy” and “untrust-worthy” communicator. They then presented several identical messages—written texts about four different topics—to two different groups of students. One group was told that the messages came from a trustworthy communicator, whereas the other one believed that the messages came from an untrustworthy source. Immediately after being confronted with the messages, as well as 4 weeks later, the students answered a questionnaire concerning the factual information of the communicated message and their personal attitudes toward the topic. The main result of this experiment was that neither the acquisition nor the retention of factual information seemed to be affected by the trustworthiness of the source but that changes in attitude were related to this factor: Students who were confronted with the trustworthy communicator changed their opinion significantly more often in the direction advocated by the communicator when they believed that the message came from a trustworthy source than when they attributed the information to an untrustworthy one. The results also confirm the hypothesis of the Sleeper Effect. After 4 weeks the two groups of students showed similar attitudes. The agreement with the position of the trustworthy communicator in the first group decreased (Forgetting Effect), and the agreement in the group of the untrustworthy communicator increased (Sleeper Effect). In further experiments, Kelman and Hovland supported these findings.

However, the Sleeper Effect as a theoretical concept is not reliable as once was thought and was criticized in the following decades. One of the main critiques is that the Sleeper Effect was demonstrated [Page 747]by Hovland under experimental conditions, which are not comparable to real life where the process of communication is much more complex.