Practicing information retrieval is key to memory retention, study finds

Learning something once, like the fact that “berg” means “mountain” in German, and studying it over and over again may do little to help you remember it in the future. The key to future recall, suggests a new study from Washington University in St. Louis, is how often over time you actively practice retrieving that information from memory.

“The take-home lesson is that learning and retention involve the active processing of information, and a passive reading of material is simply not enough to retain it well,” suggests Henry L. “Roddy” Roediger III, Ph.D., study co-author and an internationally recognized scholar of human memory function at Washington University.

Henry L. “Roddy” Roediger, III

“If a person wants to remember an event or some information over the long term, it must be actively engaged, and retrieving information from memory serves that purpose well,” he explains. “Repeated retrieval over time is critical to effective, long-term retention.”

The study, published in the Feb. 15 issue of the journal Science, is co-authored by Roediger, the James S. McDonnell Distinguished University Professor in psychology in Arts & Sciences, and his former doctoral student, Jeffrey D. Karpicke, Ph.D., now assistant professor of psychological sciences at Purdue University.

Their findings confirm what poor test-takers have known all along — doing well on an exam often has less to do with what you have read or been exposed to, and everything to do with your ability to retrieve that information from memory when prompted.

“If a student is studying for a test, especially a short-answer or essay test, he will be asked to retrieve certain information that was covered,” explains Roediger. “What better way could there be to prepare for the test than to engage in the same processes — the active retrieval of information — that will be required on the test?”

Science has explored the relationship between study and testing success for more than 125 years, but what sets this study apart is its focus on the factors that most influence retention after something is learned well enough to be recalled for the first time.

In the experiment, participants used a computer procedure that acted like flash cards to study a foreign word translation just long enough to recall its meaning one time. They were then divided into three groups in which they either kept studying the word, but not getting tested on it; kept getting tested on the word, but did not study it any more; or neither studied the word nor were tested on it.

“Surprisingly, it turns out that repeated retrieval after a (word) pair was recalled once was the critical factor,” says Roediger. ” Repeated study of the pairs after they could be recalled (compared to no repeated study) did not matter a bit. Repeated retrieval mattered a lot.”

The bottom line, says Roediger, is that active retrieval appears to be critical to both learning and retention. Rather than waiting until the test is in front of them, students should be practicing information retrieval as a routine part of their exam preparation. Flash cards can be effective tools for both third-graders studying multiplication tables and college students learning anatomy, he said. Karpicke and Roediger also believe that the results will apply to other, more complex materials in future research.

“Now we have some pretty powerful evidence that during a test there are cognitive processes happening that actually promote learning,” adds Karpicke. “Testing is not just an assessment of what you studied. The act of retrieving information actually improves memory because you are practicing a skill. And that’s the exact same skill you are going to need to retrieve that information again and again.”