Bandwagon Fallacy

Also called argumentum ad populum, appeal to popularity, or appeal to the masses

“A lot of parents at my kids’ school say this diet heals the gut.”
“Then it must be true.”

You commit the bandwagon fallacy when you claim something must be true because many people believe it or are saying it. This fallacy can also show up as thinking something is good because everyone is doing it: “All the parents at our school are signing their kids up for this brain-training app, so it must be good for learning.” Popularity isn’t evidence of effectiveness; in this case, it might just be evidence of strong marketing.

We often commit this fallacy accidentally because repeated claims are more likely to feel true. This psychological phenomenon is called the illusory truth effect. Social media can exacerbate it.

Other examples:
“Gestalt language processing must be true because so many people are talking about it.”
“Parabens must be bad because a lot of people avoid them.”

Watch the opposite fallacy, too: “I’m right because I’m going against the grain.” That’s an appeal to anti-popularity. It still relies on (un)popularity as a proxy for truth.

Next fallacy (Historian’s Fallacy)

Back to the Logical Fallacy Handbook

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