How a dodgy source will persuade you better - the sleeper effect

by Dorian Minors

June 5, 2015

Analects  |  Newsletter


Do you believe in subliminal messaging? The idea of secret messages influencing our thoughts without our knowledge is a scary idea. Fortunately the research indicates that although it might have some effects, it won’t make you do anything you didn’t...

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Do you believe in subliminal messaging? The idea of secret messages influencing our thoughts without our knowledge is a scary idea. Fortunately the research indicates that although it might have some effects, it won’t make you do anything you didn’t plan to do anyway. At least subliminal messaging has the decency to be subtle. The ‘sleeper effect’ is far more insidious. Like the Merle to The Walking Dead’s Daryl; just busts down the door and changes your mind whether you want it to or not.

It can last for months

The 'sleeper effect' was first noted by the American military (well, Carl Hovland on the military's behalf), trying to see if propaganda had the desired effect in WWII. It didn't. The propaganda had no obvious effects on the soldier's attitudes. It wasn't until much later than anything interesting happened. Over two months in fact. Nine weeks following the viewing, the soldiers who had seen the propaganda had a significantly different attitude about the war than those that hadn't. Does this mean the propaganda worked? Hovland reckoned so. He said the brain eventually forgot where the information came from (propaganda) but not the message and so the message eventually got through. Or that the message and the source simply became dissociated over time. Since then the psychological community has been back and forth about the issue for  obvious reasons:
  • Correlation does not mean causation - the two things might be linked, but we don't know what's influencing what or if they even affect each other at all (it would be like linking the rise in autism to organic food purchases, you could say they affect each other and the data is convincing, but they probably don't).
  • In the course of months, any changes in something might have hundreds of other influences that could have an effect. This link could simply be the reflection of changes in some other variable(s) (like icecream purchases and drownings are linked, not because icecream causes drownings but because hotter weather = more icecream bought and more people are swimming).
  • Persuasion should decrease as time goes by. More time should equal less effect not the other way around.

It only works if three elements line up

The fact of the matter is that researchers have vacillated between finding the sleeper effect and not finding it for over fifty years now. The most persuasive research (see what I did there?) seems to indicate that for the sleeper effect to work, there has to be three elements:
  1. The message has to be initially powerful. It has to make a significant impact on the viewer emotionally so that the mind remembers the message very well.
  2. It has to come from a clearly distrustworthy source. This one seems counterintuitive but the logic goes that we don't process the fact that the source is distrustworthy very well. Over time that degrades and the message remains.
    • It's most effectice if we learn that the source isn't trustworthy AFTER we learn the message, that way the message makes more of an impact first
  3. Finally enough time needs to pass for the source to be dissociated (or forgotten) but not enough that the messages influence disappears before the message is reinforced. Otherwise you're relying solely on the internalisation of the message which may not be enough to change the attitude in the long term (i.e. you might change the attitude but can you maintain that change?)

What that means for us

Well, the sleeper effect is pretty fragile. It breaks if those three elements don't align perfectly (or at least the research seems to lose it). So:
  • Find out the source of information ASAP, especially if a message particularly surprised or moved you. The sooner you know, the less effect the message might have if it's rotten
  • Also, if you go to some effort tracking things down, you'll process where it came from better. You want to really link a bad source to a bad message so it doesn't slip through your filters
  • If you're hearing a message for the second time, do the above again! Don't let that reinforcement happen under your radar.
  • If you're trying to convince your friends to come to some awful club for support as you meet your newest blind date or Tinder match, you might want to hold off telling them where you found out how 'good it is' until after you persuade them to come.
Speaking of secret messages, want to know about hypnotism? Find out the truth about four common myths here. Or for something that has a much more noticeable effect, why don't you learn why small talk is so awkward (and how to fix that). Giving you the dirt on your search for understanding, psychological freedom and 'the good life' at The Dirt Psychology.

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