Quizzing yourself or rereading

Many high school students study by rereading their notes. Researchers wanted to know whether retrieval practice, recalling information from memory without looking at it, produces better long-term memory than rereading the same material for the same amount of time. They hypothesized that students who practiced retrieval would recall more of a passage one week later than students who reread it.

The participants were 132 students, ages 15 to 18, from three public high schools in one Midwestern US city. They volunteered from psychology and biology classes. Of the 132 students, 74 identified as female, 56 as male and 2 as nonbinary, and all read English fluently. An institutional review board (IRB) approved the study. A parent or guardian of each student gave written informed consent, and each student gave written assent.

Students were randomly assigned to a retrieval-practice group or to a rereading group, which served as the control group. All students read a 900-word passage about how volcanoes form for 8 minutes. The retrieval-practice group then spent 10 minutes writing down everything they could remember with the passage taken away, while the rereading group spent the same 10 minutes rereading it. Before leaving, each student predicted their score on a later test. One week later, all students took a 20-question short-answer test on the passage. Long-term recall was the number of questions answered correctly out of 20, scored by two graders who did not know each student's group. Students were told they could stop taking part at any time with no effect on their grades, and scores were stored under code numbers instead of names. After the final test, the researchers explained the purpose of the study to every student and taught the rereading group how to use retrieval practice.

One week later, the retrieval-practice group had a mean score of 13.6 out of 20 and the rereading group a mean of 10.2, a statistically significant difference. The rereading group had predicted higher scores than the retrieval-practice group (see table).

Retrieval practice produced better recall after a week, even though the students who used it expected to do worse. The researchers noted that all students came from one city, studied a single science passage and were tested only once, one week later.