Sleeper effect

The sleeper effect is a psychological phenomenon that relates to persuasion. It is a delayed increase of the effect of a message that is accompanied by a discounting cue.

When people are exposed normally to a persuasive message (such as an engaging or persuasive television advertisement), their attitudes toward the advocacy of the message display a significant increase.

Over time, however, their newly formed attitudes seem to gravitate back toward the opinion held prior to receiving the message, almost as if they were never exposed to the communication. This pattern of normal decay in attitudes has been documented as the most frequently observed longitudinal pattern of persuasion research (Eagly & Chaiken, 1993).

In contrast, some messages are often accompanied with a discounting cue (e.g., a message disclaimer, a low-credibility source) that would arouse a recipient’s suspicion of the validity of the message and suppress any attitude change that might occur by exposure to the message alone. Furthermore, when people are exposed to a persuasive message followed by a discounting cue, people tend to be more persuaded over time; this is referred to as the sleeper effect (Hovland & Weiss, 1951; Cook & Flay, 1978).

For example, in political campaigns during important elections, undecided voters often see negative advertisements about a party or candidate for office. At the end of the advertisement, they also might notice that the opposing candidate paid for the advertisement. Presumably, this would make voters question the truthfulness of the advertisement, and consequently, they may not be persuaded initially. However, even though the source of the advertisement lacked credibility, voters will be more likely to be persuaded later (and ultimately, vote against the candidate disfavored by the advertisement).

This pattern of attitude change has puzzled social psychologists for nearly half a century, primarily due to its counter-intuitive nature and for its potential to aid in understanding attitude processes (Eagly & Chaiken, 1993). It has been a very widely studied phenomenon of persuasion research (Kumkale & Albarracín, 2004; see also Cook & Flay, 1978). 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 Gruder et al. (1978).

One of the more challenging aspects that the sleeper effect posed to some researchers in early studies was the sheer difficulty of obtaining the effect.

The sleeper effect is controversial because the influence of a persuasive communication is greater when one measures the effect closer to the presentation instead of farther from the time of the reception.

After attempting to replicate the effect and failing, some researchers suggested that it might be better to accept the null hypothesis and conclude that the sleeper effect does not exist.

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