Mind & Body

The Moses Illusion Shows How Bad You Are at Fact-Checking

Can you come up with the answers to these questions?

  1. How many of each animal did Moses take on the Ark?
  2. What's the nationality of Thomas Edison, inventor of the telephone?
  3. What were the first words uttered by Louis Armstrong when he set foot on the moon?

If you answered "two," "American," and "One small step for man ..." congratulations: you got every question wrong. As we're sure you're aware, it was Noah, not Moses, who built the Ark; Alexander Graham Bell who invented the telephone; and Neil Armstrong, not Louis Armstrong, who went to the moon. You knew that, of course. So why did the questions fool you? It's all in how your brain processes information.

80% of People Can't Be Wrong (Can They?)

This bit of trickery is called the Moses Illusion. It shows how bad you are at picking up on errors in your everyday life. Researchers have fooled countless volunteers in countless labs while trying to figure out what circumstances make this happen and what they can do to help people spot more falsehoods. In the original 1981 study demonstrating this illusion, more than 80 percent of people missed the fact that Moses wasn't involved in the Ark even though they had previously proven that they knew that. That's despite the fact that identifying erroneous questions like this was literally one of their tasks: they either had to answer the question, say "don't know," or say "wrong" if there was something wrong with the question.

The Moses question tripped people up the most — only around 40 percent of people were fooled by questions like "What was the nationality of Thomas Edison, inventor of the telephone?" A study published in 2000 in the journal Psychological Science explains why. UCLA researchers figured out that there are two ways people are easily fooled by this illusion: if the swapped names are "semantically similar" (on the same topic, the way Moses and Noah are both from the Bible) or "phonologically similar" (sound the same, the way Moses and Noah are both two syllables with an emphasis on the first syllable, which has an "o" sound). With that discovery, the researchers came up with questions that had both qualities in order to test what they called the "Mega-moses illusion." Sure enough, a question that swapped out the name "Andrew Johnson" for "Lyndon Johnson" — also a former U.S. vice president with a two-syllable first name and the same last name — fooled more people than questions with just one of those elements at play.

Fool Me Once

Sure, it's easy to fool people. But is this actually important beyond letting a few scientists have a laugh? Unfortunately, yes. Vanderbilt psychology professor Lisa Fazio, who wrote about this phenomenon in The Conversation, has shown in her own studies that illusions like this can lead people to pick up false information about the world. When she and her team had people read fictional stories that referred to things like "paddling around the largest ocean, the Atlantic," people were more likely to say the Atlantic was the world's largest ocean, even though they had correctly answered "Pacific" on a test they took two weeks before reading the stories.

Even worse, many attempts to help people avoid this tendency have backfired. Researchers have tried giving people more time to read the questions and printing the important information in red ink, and it just made people more likely to answer incorrectly.

Luckily, the thing that's been proven to work is a practice we can all do, especially as we wade through social-media feeds full of sensational headlines and "fake news." When people are asked to play fact-checker, correcting errors as they read, they're much less likely to pick up false information than people who just read what they're given. The takeaway is clear: assume anything you hear or read could be wrong, and you're more likely to notice when it is. If you do that, you'll be just like Einstein, the inventor of electricity.

To be right more often, you have to know why you're wrong. For that, check out Carol Tarvis's amazing book on confirmation bias, "Mistakes Were Made (but Not by Me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts." We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Ashley Hamer May 17, 2018