The Lag Effect

If you’ve ever crammed for a test the night before, you probably remember how quickly that information disappeared after the exam. That’s because cramming may help you remember something short-term, but it doesn’t help it stick in your brain. That’s where the Lag Effect comes in — a memory phenomenon that shows you’re more likely to remember something if you review it after a delay, rather than immediately repeating it over and over (this is similar to spaced repetition, but this is about how it occurs psychologically without deliberate practice).

In simple terms, the Lag Effect means that spacing out your study sessions over time is more effective for long-term learning than studying the same material back-to-back. When you wait a bit before reviewing something, your brain has to work a little harder to recall the information. This added effort actually strengthens the memory, making it more durable. It’s counterintuitive — forgetting a little helps you remember more.

This concept was explored in depth by researchers Cepeda, Pashler, Vul, Wixted, and Rohrer in a 2006 study titled “Distributed Practice in Verbal Recall Tasks”, published in Psychological Bulletin. They examined dozens of studies on how humans retain information and found that spaced repetition consistently outperformed massed practice (cramming). Their work built on even earlier findings from the early 20th century by Hermann Ebbinghaus, who charted the “forgetting curve” — showing how quickly we forget if we don’t reinforce memory at spaced intervals.

The Lag Effect isn’t just for students. It applies to learning a new language, mastering an instrument, or even remembering names at work. The trick is to allow some forgetting to happen before you re-engage with the material. That brief struggle to recall it strengthens your brain’s ability to store it long term — much like working a muscle at the gym.

So next time you want to truly remember something — don’t keep hammering away at it in one go. Let it lag, then return. Your brain will thank you later.