With the fall semester coming to a close, a Purdue University psychologist has some advice for all those college students who are poring over their notes in preparation for finals. Don't.

In a paper recently featured in the Journal of Experimental Psychology: General, psychologist Jeffrey D. Karpicke suggests that students spend their study sessions testing themselves repeatedly, improving their memory retrieval skills, as opposed to cramming for tests using written notes. He says this strategy will make recalling the information much easier when the pressure is on.

Karpicke found in his study that college students are more likely to invest their time in repetitive note reading, and those who do practice retrieval spend too little time on it.

"This is called retrieval fluency," he says. "If you practiced recalling information even a few more times, it would produce big gains in learning and long-term retention. The reason people don't keep testing themselves is because they are tricked by retrieval fluency. The answer comes to mind so easily the first time that they think they know it and drop the card from further self-testing. But this is not a recipe for good long-term learning."

"My research found that this happens because there is an illusion about how much a person is actually learning while they are self-testing," said Karpicke.

The illusion takes root when students feel answers come to them easily as they practice testing. For example, students using flashcards to study may eliminate certain cards when they believe they know that material well.

The findings are based on four experiments with 150 college students in various studying situations on Swahili-English vocabulary words. Students in each experiment learned vocabulary words from a computerized flashcard format, and then the conditions were varied based on studying techniques assigned by Karpicke or selected by the participant. The students returned a week later for final testing.

No matter if the students selected their own studying strategy or it was assigned, they all learned better when self-testing all of the material from the electronic flashcard format. Students didn't do as well on the final test if they dropped material as they learned it during self-testing.

The students whose studying techniques were assigned received computer prompts on what to study and even how to study it at times. Some of the students in the experiment could select how they wanted to study, and they were likely to drop the vocabulary words they felt they knew well. As a result, many could not remember the words when they returned a week later for the final test.

"What is surprising is that we know practicing retrieval by self-testing is really powerful, and yet people don't use it, or don't use it well," he said. "These are college students who are generally successful academically, so this just shows how powerful the illusion can be."

: Karpicke, J. D., 'Metacognitive control and strategy selection: Deciding to practice retrieval during learning', Journal of Experimental Psychology: General 2009, 138, 469-486; doi: 10.1037/a0017341