Why Does Cramming Get a Bad Rap?

Whether it was studying for a biology test, writing a philosophy paper, or prepping for seating auditions, I was always that student who seemed to be cramming all my preparation into the last possible moment. Furiously scanning notes until the teacher said “put your books away.” Or pulling an all-nighter and typing madly until the deadline gave me no choice but to finish up whatever I had and click print. Or even, trying to learn and memorize the last movement of a concerto a few days before the performance, even though I had known about it for months.

I hated being a last-minute studier and practicer of course, as working in this way was unnecessarily stressful. It’s really a special kind of academic torture to try to concentrate and make sense of complex ideas when your brain keeps fading in and out because you’re totally sleep deprived and have gone past the limits of the amount of information anyone should every try to digest in a single day. But for better or worse, I usually rose to the occasion and got through it in pretty decent shape.

So stress and sleep-deprivation aside, why does everyone seems to be so down on cramming?

Is it really so bad? Or might cramming actually work better than people give it credit for?

1 study session or 2?

Well, it all depends on what you mean by “work”.

Let’s say you have 4 hours to study for a test (or practice for a first rehearsal). Would you rather use all 4 hours in one marathon study session? Or split it up into two 2-hour sessions across two days?

In one study, 116 students were taught a new mathematical procedure, and given a set of 10 practice problems to reinforce what they had learned. But one group of students did all 10 problems in a single session, while the other students did 5 problems in one session, and the other 5 in a second session the following week.

A week later…

A week after their study session, everyone was tested to see how much they could remember.

Which group do you think performed better on the test?

Well, actually, there was no difference! Both groups scored about a 70% on the test. So in this case, it seems that “cramming” all the practice into one session worked about as well as spacing practice out over two sessions. Hmm…

Three weeks later…

To see if these gains would last, all the students were tested again three weeks later. And this time, there was a dramatic difference in performance. The students who split their practicing into two sessions scored ~64%. Those who did all their practice in one session only scored ~32%.

By simply spacing practice out, with no increase in practice time, the distributed group retained ~67% more of what they learned than the group which crammed. So sure, cramming “works” if that is defined by being able to do ok on a test in the immediate present. But if we define “work” as that which leads to long-term learning, then hmm…cramming doesn’t seem to be so effective after all.

Motor memory in mice

In a more recent study, mice were trained to track fast-moving images (kind of like humans tracking the ball in a ping pong match).

They were trained on different practice schedules though, with some mice doing all 900 practice trials in one session, and others doing 225 practice trials in 4 different sessions, with an hour of space between each practice session¹. None of the mice did very well at the task at first, but got better with practice.

Like the math study, the mice which crammed, were able to retain their training for about a week. By comparison, the mice which got a 1-hour break between practice sessions were able to remember what they learned for over four weeks.

What’s going on?

Even more interestingly, the researchers in this study were able to identify a potential neural mechanism that accounts for this difference in long-term memory retention. Despite the spaced practice and massed practice mice both achieving similar levels of performance in training, the spaced training resulted in observable structural changes in the brain quite rapidly – within 4 hours of training. The massed training resulted in neural changes as well, but much more slowly. Their changes occurred gradually over the course of about 5 days – but of course, were quickly lost after about a week.

So if these findings could be applied to practicing, it seems that how we sound in the practice room and the level of performance we achieve can be rather deceptive. Practicing in one massed session without a break, and practicing in spaced-out sessions with breaks may enable us to get to the same level of playing in the same amount of time. So in the short term, it might seem like both strategies work equally well. But if the way we practice has not affected the underlying memory structures in our brain, our long-term retention of these skills will be weaker.

The verdict

So yes, cramming does work, in the sense that if you have a test or rehearsal tomorrow, cram away. You’re pretty low on options at that point anyway, and it’ll help you get a fair amount of stuff into short-term memory which is certainly better than nothing.

But if you actually want to remember what you learn, and make your investment of study time pay off in the long term, then space things out!

Additional reading

Ever wonder why cramming feels more effective even though it’s not?

The Worst Way to Learn @BBC

1. Other intervals were tested too, like 10, 20, and 40 minutes, but 60 minutes was the most effective.