True or False

True or False

A recent study suggests that correcting false information can sometimes make matters worse. You'll hear why in this Science Update.


How warnings turn into endorsements. I’m Bob Hirshon and this is Science Update.

If you’re told that a particular drug doesn’t cure arthritis, there’s a good chance you’ll start to think it does.

That’s according to Ian Skurnik at the University of Toronto and Carolyn Yoon at the University of Michigan. They found that when people were told a statement was false, they remembered the statement itself much better than the warning. Yoon says older adults were especially vulnerable.


After even half an hour and especially after something like three days, they are much more likely to think that a false piece of information is actually true.

She says it’s more effective to state what really is true, rather than warn people about things that aren’t. This could apply to everything from consumer safety warnings to political ads. I’m Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

This study shows the importance of challenging your assumptions. Suppose a company ran misleading ads for a drug called Perfectil. Suppose the ads said that Perfectil cures cancer, even though it doesn’t.

If you were in charge of correcting the error, your instinct might be to run ads saying “The claim that Perfectil cures cancer is untrue. Perfectil does not cure cancer.” You wouldn’t necessarily expect everyone to see the ad, or remember it, but at least those who do remember it would have the right information.

Yoon and Skurnik, both business professors, found that this isn’t necessarily so. In a number of different experiments, they showed that the memory of the statement itself far outlasts any kind of disclaimer or warning that’s attached to it. This was true especially in older people, but it happens in everybody to some extent. So even just a few hours after being told a statement wasn’t true, some of their subjects started to believe it was true.

In short, you can make a lot of people believe that daffodils cause cancer by telling them that daffodils don’t cause cancer. Weird, right? Now imagine that you’re telling them something really important: for example, that a particular drug isn’t safe for people with high blood pressure. If a warning like that backfires, the results could be deadly.

The findings have political implications as well. Candidates often run ads disputing their opponents’ attacks. But according to this study, telling America that “Senator Smith never voted for that tax increase” may actually make more people believe that she did vote for it. That’s because as time goes on, people just remember the Senator’s name and the tax increase, not the “never” part.

A more effective ad, according to the researchers, might say “Senator Smith has always fought for lower taxes.” Here, there’s no negative: only the positive connection between Senator Smith and lower taxes. The downside to the findings is that they suggest that an unethical politician can make false charges seem true just by repeating them as often as possible. But even if their opponents can’t stop them, at least they can avoid unintentionally helping them out.

Now try and answer these questions:

  1. What assumptions about memory and human nature does this study challenge?
  2. Can you think of examples from real life that support this study?
  3. Besides consumer safety and politics, describe another situation to which these findings might apply.
  4. If you were a teacher, how might you use these findings to guide your teaching?

For Educators

Identifying and Understanding the Fallacies Used in Advertising, a lesson from ReadWriteThink, alerts students to the fallacies that surround them every day. It also introduces them to the tools needed to examine such falacies critically.

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