In the late 1800s, German psychologist Hermann Ebbinghaus set out to memorize hundreds of nonsense syllables and discovered it was more efficient to space out his study sessions than to try to learn long lists in one sitting.
Hundreds of studies carried out since have established the power of what is now known as the "spacing effect" and how people can better remember faces, words and historical facts if they spread out their study time rather than attempting one long cram session.
But most of the experiments have involved adults, said York University psychologist Nicholas Cepeda, who has begun to study the "spacing effect" in Ontario classrooms. He wants to come up with simple recommendations that will help teachers capitalize on the effect to improve how much students learn and retain.
What kind of spacing is most effective? Should lessons and subsequent review sessions be a week apart? Or is a gap of several months better? Are cumulative tests an effective teaching tool because they cover material taught earlier in the year as well as the most recent lessons?
Dr. Cepeda is probing deeper questions as well. What is it about the brain that makes the "spacing effect" so powerful? What can it tell us about how memory works? Dr. Cepeda was recently awarded a $100,777 grant from the Canadian Foundation for Innovation to buy equipment that will allow him to measure the electrical activity in the brains of children when they learn something for the first time compared to when they study it again several months later.
He expects that relearning material a second or third time is the result of different, more intense, brain activity.
"If you have forgotten the material, the brain may think it has to pay more attention."
As well, he said, when people store a memory at different times and in different circumstances, it gives them more contextual cues - including related facts or information - that can help them retrieve it.
For example, a child memorizing the three times table learns that 3 X 8 = 24. The next lesson also covers the four times table, and she learns that 4 X 6 = 24. Remembering that the two questions have the same answer can help her retrieve the correct response to either one if she gets stuck.
Dr. Cepeda plans to use an electroencephalogram or EEG, but researchers in United States, China and Japan have turned to brain imaging to investigate the neural underpinnings of the "spacing effect," and what brain regions are involved. The effect has also been documented in rats, fruit flies and bumble bees and researchers are doing experiments that involve these animals to learn more.
In humans, it has been shown in infants, preschoolers, elementary and high school students and adults of all ages, including the elderly.
"It must be something very basic," Dr. Cepeda said.
A number of teams have found that the "spacing effect" can help patients who have suffered a traumatic brain injury and as a result have difficulty learning and remembering.
Dr. Cepeda is interested in its application in the classroom.
In one experiment, he found that Grade 5 students in an Ontario school remembered significantly more words in a vocabulary list they learned in two sessions spaced a week apart than in a single lesson. But he said he understands that many teachers may not have the time or inclination to teach the same thing several times.
Quizzes could offer a quick and easy way to tap into the power of the "spacing effect," he said. Research has shown that taking a test is a more effective way to learn than extra study or review time. It is important, however, that students learn the correct answers after they take the test.
Dr. Cepeda also wants to assess the value of cumulative tests, which include questions on material students learned earlier in the year and could be a valuable teaching tool.
He said it is frustrating how little research is done to translate the discoveries psychologists and neuroscientists make about memory and learning into effective teaching strategies. In the United States, the Institute of Education Sciences funds this kind of research, but there is no equivalent agency in Canada, said Dr. Cepeda, who has applied to the U.S. institute to do more studies in Toronto classrooms.
"As psychologists, we are sometimes scared to tell teachers what to do because we may end up telling them to do something that works in the lab that doesn't work in the real world. We really do need to be testing these things in the classroom."