Students who break into a cold sweat at the thought of a pop quiz might feel better once they learn about a side effect of test-taking: The practice appears to enhance memory, possibly even more than studying. What's more, according to a new study, testing also helps students remember material that wasn't on the exam in the first place.
Over the past several years, cognitive scientists have documented a phenomenon called the "testing effect," in which taking a test, rather than studying, boosts an individual's ability to remember the material later on. The research led psychology doctoral student Jason Chan and his colleagues at Washington University in St. Louis, Missouri, to wonder whether testing also affects memory for untested materials.
To test the theory, the team had 84 undergraduate students read a passage about toucans, a topic the researchers believed would be unfamiliar to psychology undergraduates. After reading the passage, one-third of the students were dismissed, one-third were asked to read an additional set of study materials that covered the same information as the original passage, and one-third were asked to take a brief short-answer test on the original material. The next day, all participants returned to take a final short-answer test, which included questions from the previous day's brief test as well as new questions.
Students who took the test the day before scored, on average, 8% higher on the second-day test than did the two groups of students who did not take the initial test. This pattern held true for test questions repeated from the previous day's test well as for questions about toucans the students had never seen before, the team reports today in the Journal of Experimental Psychology: General.
The experiments suggest that taking a test improves memory of related but untested material, says Chan. "If students take a test on only half of the materials in a class, their memory of the other half is not just laying around and not being activated," he says, suggesting several tests over a semester might improve students' performance on a final exam. While the study did not explore a possible mechanism, the authors suggest that when people read a test question, they may automatically think of related information. Retrieving the related information may enhance their memory of it, helping them to access that information at a later time.
"This sounds like the kind of thing that would be very beneficial to introduce to classroom practices," says Mitchell Nathan, an educational psychologist at the University of Wisconsin, Madison. Indeed, cognitive psychologist Steve Lindsay of the University of Victoria in British Columbia, Canada, says that evidence for the testing effect is compelling enough that he now begins every class with a pop quiz of the previous day's lecture material.