Sleeper effect: characteristics of this persuasive phenomenon

This psychological effect linked to the assimilation of beliefs and messages has been much discussed.

If we were told that, sometimes, we would believe a political speech or a propagandistic advertisement a few months after seeing it rather than at the very moment we are receiving it, we would surely say that this is simply impossible.

However, in both social and experimental psychology, the existence of the sleeper effect has been proposed.a strange phenomenon that occurs when, after a few weeks, our attitudes towards a persuasive message change significantly.

This phenomenon is extremely rare, and it has even been suggested that it is not something that actually happens, but it has been explained in various ways and has been tried to be addressed experimentally. Let's take a closer look at what it is all about.

Sleeper effect: what is it?

The effect of the sleeper is a curious phenomenon, proposed from the social and experimental psychology, which maintains that, sometimes, a message that was intended to be persuasive from the beginning, instead of being assimilated immediately, will receive greater force after a certain amount of time has passed..

Normally, when something is said or shown that carries with it a message, be it political, of opinion, ethical or of any other kind, the person usually manifests a series of immediate attitudes with respect to the content of the message itself. Depending on how credible he/she finds what is being said in the message, the person will basically make one of the following two decisions: to accept what is being said or simply not to accept it.

Regardless of whether or not he believes that the information he has just received is true, it is normal that, after a certain period of time, he will forget the content of the message. That is to say, if a person is exposed to a message of any kind, it is normal that it has caused a greater impression immediately after having received it than after a few weeks.

However, and according to how the sleeper effect is defined, what sometimes happens is that the message, which originally was not taken as credible, is taken into consideration after a few weeks.. Not only does the person continue to remember what was said to him some time ago, but he also manifests a series of favorable attitudes or attitudes in accordance with what was originally said.

This phenomenon, as described here, may seem counter-intuitive. If you doubt the content of a message from the beginning, especially because you doubt the veracity of the source of information, it is normal that, with the passage of time, you either end up forgetting or being even more critical of what was said in it.

Historical background

The origins of the definition of this particular phenomenon can be found during the Second World War. The United States had a clear interest in keeping morale high among the ranks, as well as convincing its soldiers of the need to help their allied countries, including Great Britain. To this end, the U.S. War Department used propaganda entertainment, especially films, to spread a message of optimism and sympathy for the Allies.

However, despite the large investment the United States was making in the production of these films did not seem to be having the desired effect.. That is why, through a series of experiments, they set out to see how the message was getting through to the troops. These experiments showed that the message they were trying to spread was not as well received as they thought it would be.

It was found that those short films that were informative in nature and sought to reinforce certain existing attitudes related to the war seemed to have a very moderate impact in the short term. However, after a few weeks, it was seen that among the troops there was a marked increase in this optimism and support for both their nation and the allied countries.

Theories behind this phenomenon of persuasion.

As we were already saying, the sleeper effect is striking for being a rather counter-intuitive phenomenon. It would be normal that, faced with a message that we doubt, the content of the message is viewed even more critically as time goes onIt is not that it will end up being seen as true after a few weeks.

Several aspects have been proposed to try to explain why and how the sleeper effect happens, although to this day there is still controversy about it and it seems that, experimentally, it is difficult to replicate it.

1. Forgetting that it is doubtful

The first to describe this phenomenon were Hovland, Lumsdaine and Sheffield in 1949. These researchers, taking the case of American soldiers, hypothesized that, some time after having received the message, it is forgotten that it has dubious aspects and the content of the message itself remains.

That is, with the passage of time, the attitudes that were manifested at the beginning are being forgotten, which makes the content of the message itself gain more prominence, generating new attitudes.generating new attitudes.

This, however, is not so simple. It is quite simplistic that people, after a while, will change their attitudes simply because they forget where a particular message came from or will suddenly believe what was said in it.

The other proposal of the same research group is that the origin of the message is not actually forgotten, what happens is that it disassociates with the message.. That is to say, it is known that it had a doubtful origin, but it is not known which one.

Faced with this fact, the person gives it greater importance, and even gives it another opportunity to 'see' it more objectively, which can affect their attitudes if the original persuasive objective of the message is satisfied.

2. Different processing of content and origin

Years after Hovland's group proposed what we have seen in the previous point, the group of Pratkanis, Greenwald, Leipe and Baumgardner offered an alternative hypothesis to the previous explanation in 1988.

This research group proposed that the effect was due to the fact that people encode the content of the message differently compared to the source from which it originates..

That is, we know how to differentiate objectively what the message entails compared to who the source is.

As content and origin are processed differently, the origin is forgotten or loses strength with the passage of time, while the content or the message itself remains.

As the content is viewed separately from its origin, it is more likely to be taken as truthful.

How does it happen?

Whatever the mechanism that can give a more objective explanation to this strange phenomenon, for the message to be remembered over time, it must meet the following two conditions:

Strong initial impact 2.

The sleeper effect can only occur if the message that was initially delivered has a strong and outstanding persuasive impact..

Although the person will not believe it, the fact that the message is strong means that it will remain in his long-term memory.

2. Message discarded a posteriori

When a message is issued by a source of information that is not considered reliable, the message tends to be discredited from the outset.

However, if the source of information is found to be unreliable, but after the message has been delivered, then the message will be better remembered, running the risk of being more suggestible in the long run..

For example, we are watching a political meeting on television and, at the end of the candidate's speech, a presenter comes on and highlights, with evidence, all the unfulfilled electoral promises made by the same candidate when he won a past election.

Although we have been given evidence that this politician cannot be trusted, having seen the evidence after having listened to the speech does not prevent us from remembering what he was saying while he was explaining what he would do if he won these elections.

After a few months, we are more likely to remember the content of the speech than the evidence that was given after it was over. after it was over.

Criticism of this phenomenon

The main controversy to which this phenomenon has been exposed is the manner in which it is given. It is very difficult to contemplate the possibility that a message that has just been broadcasted and whose audience did not believe it or strongly doubted it, will eventually be taken into account and even significantly modify the attitudes of those who originally received it.

It has been practically impossible to replicate this phenomenon in laboratory conditions.. The theories put forward by both Hovland's and Pratkanis' groups are not at all clear about what they mean by persuasive message and unreliable source. Experimental psychology strongly doubts that this phenomenon is plausible in real life beyond its hypothetical approach.

Bibliographical references:

• Capon, N. & Hulbert, J., "The Sleeper Effect - An Awakening", Public Opinion Quarterly, Vol.37, No.3, (Autumn 1973), pp. 333-358.
• Cook, T. D., Gruder, C. L., Hennigan, K. M., & Flay, B. R., "History of the Sleeper Effect: Some Logical Pitfalls in Accepting the Null Hypothesis", Psychological Bulletin, Vol.86, No.4, (July 1979), pp. 662–679.
• Hovland, C.I., Lumsdale, A.A. & Sheffield, F.D, Experiments on Mass Communication: Studies in Social Psychology in World War II: Volume III, Princeton University Press, (Princeton), 1949.
• Hovland, C.I., Weiss, W., "The Influence of Source Credibility on Communication Effectiveness", Public Opinion Quarterly, Vol.15, No.4, (Winter 1951), pp. 635–650.
• Pratkanis, A. R., Greenwald, A. G., Leippe, M. R., & Baumgardner, M. H. (1988). In search of reliable persuasion effects: III. The sleeper effect is dead: Long live the sleeper effect. Journal of Personality and Social Psychology, 54(2), 203–218. https://doi.org/10.1037/0022-3514.54.2.203