Illusion of Knowledge

Interesting write up by Daniel Simons, co-author of "Invisible Gorilla" on how best to detect and overcome the illusion of knowledge. We normally mistake familiarity with deeper understanding and this leads to what is known as the "illusion of knowledge." What is most interesting about the "illusion of knowledge" is that it is so easy to detect but then how seldom do we actually detect and rectify it. The write-up below is an eye opener.

Think you know the best way to study? Better test yourself.

By Daniel Simons, on January 25th, 2011

Imagine you’re taking an introductory psychology class and you have to study for your first test. You’ve read the assigned text, and now you three more days to prepare. What should you do?

1. Re-read the text once more each day
2. Spend each day studying the text to identify critical concepts and the links among them
3. Quiz yourself the first day, reread the text the second day, and quiz yourself again the third day

Do you think you know the answer?

Students in my introductory psychology class regularly come to my office hour after failing the first exam to ask what they did wrong. Some even claim to have spent hours re-reading the text, highlighting important concepts, and even taking notes. Where did they go wrong?

In The Invisible Gorilla, Chris Chabris and I argue that these students fell victim to the Illusion of Knowledge—they thought they had a deeper understanding of the material than they actually did. But why did they have that mistaken intuition? The answer seems to be that they mistook familiarity and fluency for real understanding.

The same principle explains why you might think you know how a toilet works when all you really understand is how to work a toilet—your familiarity with using a toilet leads you to the false impression that you know far more than you actually do. What’s most remarkable about the illusion of knowledge is how easily we can overcome it. What’s most disturbing is how rarely we actually do.

To determine whether you have genuine knowledge about toilets, just ask yourself a few diagnostic questions and force yourself to answer. For example, how does water fill up the bowl? What causes the water to leave the bowl? Why does water leave the tank? Each time you can produce the correct answer, ask yourself a slightly deeper, next-step question. Eventually, you will reach the limits of your knowledge. You’ll know what you don’t know.

The same principle applies to studying and learning a text. If you read the text over repeatedly, you will familiarize yourself with it, but you won’t know the limits of your knowledge. Only by testing whether you can produce the answers yourself can you verify what you know. And, in a study just published online in Science, Karpicke and Blunt find that testing yourself leads to more effective learning and retention than does re-reading the text repeatedly or even mapping the core concepts of the text. It works because it overcomes the illusion of knowledge. Forcing yourself to test your knowledge is the most reliable way to identify the limits of your knowledge.

The reason my students come to me after failing their exam is that they have the wrong intuitions about what makes for effective learning. They thought that reading the text repeatedly would engender the best learning, and it apparently never occurred to them to check their own understanding. The same was true for Karpicke & Blunt’s subjects. They predicted that repeated studying would lead to better learning than would trying to retrieve what they had already learned. That is, they favored the approach that would lead to illusory knowledge rather than real knowledge.

Source cited:

Karpicke JD, & Blunt JR (2011). Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping. Science (New York, N.Y.)PMID: 21252317