So, you have great news to share. Let’s say your new product works even better than expected, or you’ve come across information that will help solve all kinds of problems. You want to tell the world about it!
…Except that the world won’t take it seriously if it comes from you. Because it’s your product, or you’re going to benefit from the new approach, or you’re an interested party. For some reason, when you own all the cows, you’re not a credible source for the health benefits of milk.
You could pay someone else to spread the message (which is where lobby groups come from). But it turns out that there’s an interesting phenomenon called the “sleeper effect” that can help in exactly this situation.
The term was first used by researchers measuring the propaganda effect of pro-World War II films on soldiers. The films didn’t produce the expected optimism, no doubt partly because the soldiers knew they were propaganda. However, they did have some subtle effects on the attitudes of those soldiers months later.
In the following decades, dozens of psychologists tried to reproduce the sleeper effect, and most of them failed. For years, many researchers assumed it didn’t really exist. However, more recent research has found that it does – but only under certain conditions.
For example, a research team led by Anthony Pratkanis asked volunteers to view different kinds of messages. Some were brand evaluations of fictitious consumer products; others were arguments for various policy issues that didn’t generally provoke strong opinions (for example, claiming that textbooks should be free in public schools). Each message was accompanied by its supposed source, which could be low-credibility (such as the manufacturer or a lobby group) or high-credibility (such as Consumer Reports or a disinterested organization). The volunteers were asked their opinions on the products or issues after various lengths of time, during which they did other tasks.
The team found that different circumstances produced different results. In most cases, the effect of a message “decayed” over time – the longer they waited between showing a message and asking for the volunteer’s opinion, the less effect the message had. However, they did see a sleeper effect under one set of conditions: when (a) the viewers paid attention to the arguments in the message, (b) the source of the information was presented immediately after the message, and (c) the viewers then thought about the credibility of the source.
Some years later, Tarcan Kumkale and Dolores Albarracín evaluated all the research they could find on the sleeper effect, including Pratkanis’ work, and came to similar conclusions: messages were most persuasive when viewers thought about the arguments being presented and when the source of the message was provided after the message itself. (They also demonstrated that the sleeper effect only occurs when the message has a big initial impact on the viewer and the message source isn’t completely trustworthy.)
So, if you’re in the awkward position described at the beginning of this post, you can at least give your message a fighting chance for long-term persuasion. Make sure it’s as strong as possible, give all the details before mentioning that you’re the source, and try to get your viewers to think about your arguments. Not exactly surprising, but worth remembering.