Taking Memory Tests Improves Long-Term Retention

Taking a memory test not only assesses what one knows, but also enhances later retention, a phenomenon known as the testing effect. We studied this effect with educationally relevant materials and investigated whether testing facilitates learning only because tests offer an opportunity to restudy material. In two experiments, students studied prose passages and took one or three immediate free-recall tests, without feedback, or restudied the material the same number of times as the students who received tests. Students then took a final retention test 5 min, 2 days, or 1 week later. When the final test was given after 5 min, repeated studying improved recall relative to repeated testing. However, on the delayed tests, prior testing produced substantially greater retention than studying, even though repeated studying increased students’ confidence in their ability to remember the material. Testing is a powerful means of improving learning, not just assessing it. In educational settings, tests are usually considered devices of assessment. Students take tests in class to assess what they have learned and take standardized tests like the SAT to assess their knowledge and aptitude. In many circumstances, such as university lecture courses, tests are given infrequently (often just two or three times a semester) and are generally perceived as a bother by faculty and students alike. We believe that the neglect of testing in all levels of education is misguided. To state an obvious point, if students know they will be tested regularly (say, once a week, or even every class period), they will study more and will space their studying throughout the semester rather than concentrating it just before exams (see Bangert-Drowns, Kulik, & Kulik, 1991; Leeming, 2002). However, more important for present purposes, testing has a powerful positive effect on future retention. If students are tested on material and successfully recall or recognize it, they will remember it better in the future than if they had not been tested. This phenomenon, called the testing effect, has been studied sporadically over a long period of time (e.g., Gates, 1917), but is not well known outside cognitive psychology. Most experiments on the testing effect have been conducted in the verbal learning tradition using word lists (e.g., Hogan & Kintsch, 1971; Izawa, 1967; McDaniel & Masson, 1985; Thompson, Wenger, & Bartling, 1978; Tulving, 1967; Wheeler, Ewers, & Buonanno, 2003) or picture lists (Wheeler & Roediger, 1992) as materials. There have been a few experiments using materials found in educational contexts, beginning with Spitzer (1939; see too Glover, 1989, and McDaniel & Fisher, 1991). However, the title of Glover’s article from 17 years ago still sums up the current state of affairs: ‘‘The ‘testing’ phenomenon: Not gone but nearly forgotten.’’ Our aim in the two experiments reported here was to investigate the testing effect under educationally relevant conditions, using prose materials and free-recall tests without feedback (somewhat akin to essay tests used in education). Most previous research has used tests involving recognition (like multiple-choice tests) or cued recall (like short-answer tests). A second purpose of our experiments was to determine whether testing facilitates learning beyond the benefits of restudying the material. In some testingeffect experiments, a study-test condition is compared with a study-only condition on a delayed retention test. When the subjects in the former condition outperform those in the latter on a final test, one can wonder whether the testing effect is simply due to study-test subjects being reexposed to the material during the test. It is no surprise that students will learn more with two presentations of material rather than one (although some of the word-list experiments cited earlier overcame this problem; see too Carrier & Pashler, 1992; Cull, 2000). To evaluate this restudying explanation of the testing effect, we had students in our control conditions restudy the entire set of material—which should, if anything, bias performance results in favor of this condition, because students who take free-recall tests (without feedback) can only reexperience whatever material they can recall. Students in our experiments studied short prose passages covering general scientific topics. In Experiment 1, they either Address correspondence to Henry L. Roediger, III, Department of Psychology, Washington University, Campus Box 1125, One Brookings Dr., St. Louis, MO 63130, e-mail: [email protected]. PSYCHOLOGICAL SCIENCE Volume 17—Number 3 249 Copyright r 2006 Association for Psychological Science took a test on the material or studied it again before taking a final retention test 5 min, 2 days, or 1 week later. In Experiment 2, students studied a passage once and took three tests, studied three times and took one test, or studied the passage four times. They then took a final test 5 min or 1 week later. We predicted that performance on immediate retention tests would increase with the number of study opportunities, because massed practice typically produces short-term benefits (e.g., Balota, Duchek, & Paullin, 1989). However, we predicted that taking tests soon after studying would promote superior retention on delayed tests relative to repeatedly studying the material. This outcome would indicate that testing has positive effects on longterm retention above and beyond any effect of re-presentation of the material during the test.