Cramming Does Not Help Create Long-Term Memories
December 26, 2013

Spaced Learning Makes For Longer-Lasting Memories, Better Than Cramming

Ranjini Raghunath for - Your Universe Online

Those last-minute cramming sessions fueled by instant noodles and coffee might help you pass your exams. But they won’t help your brain remember things in the long term.

Scientists have long known that learning with breaks in between helps your brain remember things longer than when you try to cram it all in one go. Called the “spacing effect,” the phenomenon was first described by German psychologist Hermann Ebbinghaus in 1885.

Researchers had previously shown that this type of spaced learning helps boost the lifetime of nerve cells in the hippocampus - the part of the brain where long-term memories are formed.

Now, a study conducted by researchers at the National Institute for Physiological Sciences, Japan throws light on what changes in the brain influence this long-term memory retention.

In their experiments, the researchers trained two groups of mice to track moving images and studied what is known as their horizontal optokinetic response - the reflex that helps you keep track of scenery when traveling in a train. One group was given breaks in between trials (“spaced” learning) while the others were given none (“massed” learning).

The mice were made to look at a quickly moving revolving image. A camera was used to track their eye movements to check for when they saw and responded to the image. After some initial difficulty, both groups of mice got used to the speed and were able to respond more quickly in subsequent trials.

However, mice that had ample rest in between trials were able to remember to adapt to the speed for a longer time, the researchers found. Giving them a break of just one hour between trials helped them remember what they had learned for more than four weeks.

The other group, which had been subjected to massed learning, was able to remember their training for only a week.

Memory retention in the hours following the training was linked to a drop in the number of nerve cell bridges and structural changes in a specific set of nerve cells called Purkinje cells. Purkinje cells play a vital role in controlling motor skills such as writing or walking. Defects in these cells can lead to poor learning or autism-like disabilities.

Changes in the Purkinje system happened very quickly for mice with spaced learning - within 4 hours after the training - while it took days for the other set of mice.

Spaced training also created repetitive peaks in specific signaling protein activity, while massed learning produced only one peak, after 20 minutes of training. As a result, recovery of information was faster, helping to form long-lasting memories in mice with spaced training, the researchers found.

The study was published in the journal Proceedings of the National Academy of Sciences.