Why Repeating Something Makes it Sound Truer

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Before I begin today’s video, I want to give a shout-out to my Patrons! They make these videos possible, and in exchange they get early ad-free videos, weekly newsletters, monthly Q&A livestreams, and a smart and kind community to interact with. If you want to get in on the action, go to You will love being a patron and you will find it very rewarding!

Anyway, last week I told you about a new study that found that watching a “rags to riches” TV show made Americans more likely to believe in “the American Dream,” that anyone can rise above their economic caste to become a success provided they have the talent and work ethic.

One thing I didn’t mention in that video, despite it being relevant, was the “availability heuristic.” I didn’t want to get too sidetracked in that video but for THIS video it is perfectly related to the topic at hand.

In the case of the “rags to riches” study, part of the results may be explained by this: maybe people were more likely to believe the “rags to riches” narrative because it’s not really something they think about very often, and they don’t really hold strong opinions on it, so watching a “rags to riches” show immediately before weighing in on it influences them because their little monkey brains just grab whatever position they most recently viewed.

You see, human brains require a LOT of energy to run, so as we evolved, we developed shortcuts that let us, generally, reach the correct conclusion without “showing the work.” Like noticing your teacher usually puts the correct answer as “C” on a multiple choice test, so when you’re out of time and have one complicated problem left to do, you just fill in “C” and hope for the best.

These shortcuts were great for keeping your great-great-great-great-etc-grandparents alive long enough to reproduce, but these days they screw us up quite often: in the case of the availability heuristic, it means that when you’re asked a question, you’re more likely to think the “correct” answer is whatever comes to mind first – the most easily “available” bit of information. And that information may be immediately available to your brain because it’s the right answer, OR because it’s, like, the thing you heard most recently, which is why when I played “Codenames” with friends last weekend the clue was “food” and my first guess was “grass,” because four hours earlier I had taken my dog on a walk and he ate so much grass he barfed. My second guess was “centaur,” which kicked off a 20-minute argument over whether or not eating a centaur is considered cannibalism. The uneasy conclusion we landed on was “it depends on which part of the centaur you eat,” with the torso area remaining contested ground.

All of this leads me to the topic of today’s video: which mythical creatures are ethical to” eat. No, no, sorry, that’s not it. It’s actually about how researchers convinced some people to maybe sort of believe completely ridiculous lies.

For a long time now, sociologists have known that you can make people believe an untruth by simply repeating it, providing that the people in question have no prior knowledge about the subject. This is known as the TBR effect, or “Truth-by-Repetition.” For instance, if I tell you that the zipper was invented in Norway (an actual example from a prior study), you’re more likely to think that’s a true statement the more you hear it repeated, despite the fact that the zipper stands proudly alongside the bazooka and the fortune cookie as an all-American invention, despite the fact that the study that used this example says it was Switzerland.

The TBR effect seems to work on any statement that has “truth ambiguity,” like “The temperature of a chicken’s body is about 104 degrees Fahrenheit” or “You will love being my Patreon patron and you will find it very rewarding!” If you don’t know for sure, repetition is going to be really effective at convincing you it’s true. I mean, one of those statements really WAS true, but was it the internal temperature of a living chicken or the fact that you will love being a patron and you will find it very rewarding? Who is to say.

There’s some additional evidence that you may even be able to make people doubt their existing knowledge by repeating a falsehood, like “The Atlantic Ocean is the largest ocean on Earth,” but the data there is messier.

Jumping into this fray is a new study that aimed to show that if you look very, very closely at the data, with a high enough level of sensitivity, you can not only make people doubt their existing knowledge with sort of plausible lies like that, but you can even make people start to believe complete absurdities like “the Earth is a perfect square.” A square! Not even a cube! A cube is at least three-dimensional!

Okay, so no one walked away from this study believing the Earth is a perfect square, but it is a bit interesting: to get very sensitive data, instead of just asking people if they did or did not believe an absurdity, the researchers asked 232 Americans to rate statements on a very big scale, from -50 (definitely false) to +50 (definitely true). They did this after they saw some of the statements repeated five times in a previous test where they only had to rate how “interesting” each statement was. 

Half the statements were incredibly stupid, like “the US was founded in 1979” and “elephants are faster than cheetahs.” 

Sure enough, most of the subjects gave higher scores to the stupid statements they saw repeated several times. They still were in the negative, but they found them slightly less false than the stupid statements they did NOT see repeated. Weird!

All of that was pre-registered, a great way to conduct experiments that I’ve talked about in the past – before the experiment started, the researchers confirmed exactly what their hypothesis was and what statistical analyses they would be performing to test it. This helps prevent researchers from knowingly or unknowingly tweaking the data to get an interesting result.

But once that was done, they drilled down a bit on the individual subjects. They found that while 53% of them did get fooled by the repetition, 19% weren’t affected at all, and 28% actually went in the opposite direction: they rated the repeated absurdities as even less true than the absurdities they hadn’t seen before.

The researchers aren’t sure why those three groups reacted differently to the repetition, so that gives them something new to dig into next time.
To conclude, I’d just like to stress that you will love being my Patreon patron and you will find it very rewarding! Learn more at

Rebecca Watson

Rebecca is a writer, speaker, YouTube personality, and unrepentant science nerd. In addition to founding and continuing to run Skepchick, she hosts Quiz-o-Tron, a monthly science-themed quiz show and podcast that pits comedians against nerds. There is an asteroid named in her honor. Twitter @rebeccawatson Mastodon Instagram @actuallyrebeccawatson TikTok @actuallyrebeccawatson YouTube @rebeccawatson BlueSky

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