Ask the Scientist

Which is the best way to study? How often? Does cramming work?
Featured Scientist: Sean Kang (, TDLC Network: IMS, in Hal Pashler's Lab

1. Which is the best way to study?
This question is very broad, and a complete answer is beyond the scope of this section because there are a multitude of factors that influence the effectiveness of studying. I will mention, however, that research done by cognitive scientists (including Prof. Hal Pashler and colleagues at TDLC) has demonstrated two key principles of human learning/memory that have important implications for how students should study or prepare for an upcoming exam. The first principle is the spacing effect, which refers to the observation that a repetition (e.g., studying the material a second time) is more effective when the two presentations are spaced apart rather than consecutive in time. The second principle is the testing effect, which refers to the phenomenon of better retention of the material when the individual has practiced retrieving the information from memory, relative to merely reading the information. In other words, being tested on the material is a potent way to enhance one’s retention of the material. These two principles can be combined to maximize the benefits—i.e., spaced (or distributed) retrieval practice – e.g., practice with a set of flashcards on Day 1, again on Day 3, then again on Day 5, etc.


2. How often? How long for each session?
In general, the more time that a student devotes to studying for an exam, the better prepared he or she will be (bearing in mind that there will be diminishing returns), but only when the study strategy is held constant. A student who uses an ineffective study strategy (e.g., re-reading his or her notes/textbook over and over) may spend more time studying overall than a student who uses an effective study strategy (spaced retrieval practice, as explained above), but the first student may not outperform the second student on the exam. There is no hard and fast rule on how often a student should study, or how long each study session should be, except that a student should devote enough time to studying such that he or she is able to cover the target material at least twice over (i.e., there is sufficient time to repeat the same material more than once, so that the student can take advantage of a spaced repetition), and that the repetitions should be spaced apart in time (it’s more beneficial to have two shorter sessions on separate days than to have one longer session where the student repeats the material again and again in that single session).


3. How long before the exam should the student start studying? Does cramming work? How does cramming affect the ability to retain what was learned?
In line with the spacing effect mentioned earlier, cramming is an ineffective study strategy. When cramming, a student typically reads his or her notes/textbook again and again, often the night before the exam. This “last-minute” preparation denies the student the benefit of spaced repetition, and results in poor long-term retention of the information. While previous lab studies comparing cramming vs. spaced repetitions sometimes found a benefit of cramming on immediate tests, these immediate tests were administered usually no more than 10 minutes after the study session. These short-term gains were invariably reversed when the test was administered after a longer delay—i.e., cramming leads to rapid forgetting. Therefore, students should endeavor to begin their exam preparation early, giving themselves sufficient time to space out their study sessions and engage in retrieval practice, so as to improve long-term retention of the material