According to Herbert F. Spitzer, an ambitious graduate student, immediate recall in the form of a test is an effective method of aiding the retention of learning and should, therefore, be employed more frequently in the elementary school. Suggestions like Mr. Spitzer's have been made for many decades, but they have never gained much traction. Now, however, a high-profile group of memory researchers at Washington University in St. Louis is working to rekindle interest in the "testing effect," as it is known. If teachers want to maximize their students' long-term learning, these scholars say, they should quiz them during every class session. And that emphatically includes college classes. The purpose of this quizzing is not to motivate students to pay attention and to study more; if those things happen, the researchers say, they are nice side effects. The real point is that quizzing, if done correctly, is a uniquely powerful method for implanting facts in students' memory.