Study skills: the science behind the power of sleep and revision
By Elizabeth Holtom
19 Mar

Elizabeth Holtom is the author of the Galore Park book Study Skills: Building the study skills needed for 13+ and beyond. As pupils follow this step-by-step, interactive guide they become confident and resourceful learners ready for the challenges at prep school and beyond.

Students are fast approaching the final exams of their prep school lives.  How effectively are they using their study skills?  Would a few changes to their schedule at home make a big difference to their exam readiness in the summer term? In this blog I look at two areas worth considering with an explanation of the science behind them.


Sleep is necessary for the consolidation of memories.  On page 6 of Study Skills 13+ I explain one reason why sleep helps with our studies:  new learning is held in temporary storage in a part of the brain called the hippocampus. Research shows that the hippocampus ‘replays’ the day's events during sleep. This strengthens new memories and prepares them for long-term storage in other brain areas.  That is why it is so beneficial to have a look at a mind map or check over a few index cards or flashcards before going to sleep.  The brain will carry on processing that information during sleep and so strengthen those connections and enhance memory. It also means that the hippocampus is ‘emptied’ and ready for new learning to be stored there the following day.

If you look at the illustrations and brief explanation on page 1 of Study Skills 13+ you will see how neurons work. Neurons are the building blocks of our brains.  As new connections are made, tiny protrusions form on the dendrites.  These are called dendritic spines. They connect to other neurons and facilitate the passage of information across synapses.

Research at New York University School of Medicine, published in 2014, showed for the first time that sleep after learning encourages the growth of these dendritic spines. Their research also showed that the activity of neurons during deep sleep, or slow-wave sleep, after learning is critical for such growth. 

It is true that we literally need to ‘sleep on it’ in order to consolidate our learning.


Last minute cramming is an inefficient way to learn.  Not only is it likely to be stressful but it also means there will be little or no opportunity for learning to be consolidated during sleep.  However, a system of reviewing will automatically guarantee that this can take place.  When we first learn something new, the connections are weak.  There may only be a few neurons connected together.  There may only be a small dendritic spine and a small synapse.  As we practise and review our learning, more neurons join in, the synapses get bigger, as do the spines.  Understanding and recall improve.

Read the section on memory – section 1.3 – in Study Skills 13+. On page 15 I explain that it is possible to forget up to 80% of what we learn after only 24 hours.  I call this the memory slide.   The technical name is actually the Ebbinghaus forgetting curve.   Hermann Ebbinghaus was a German psychologist who pioneered the study of memory.  In 1885 he put forward the theory that there is a decrease in the brain’s ability to retain new learning unless it is consciously reviewed within 18 minutes, after 1 day, 1 week, 1 month and 6 months.  He called this spaced repetition.  I have simplified this by suggesting a review after a 5 minute break, 1 day later, 1 week later and also the night before a test or exam.

The golden rule is ‘little and often’.  Students should chunk their learning into manageable amounts, working for up to half an hour, taking a short break, then reviewing what they have learnt before continuing with something new.  They could use a numbered concertina file to keep them on track with their regular reviews.  There is a detailed explanation of how to use one on page 16 of Study Skills 13+.

More tips


  • Make sure your children have a good sleep routine.  They should switch off their devices about an hour before going to bed.  The blue wavelength light they emit keeps the brain on the alert and inhibits the production of melatonin which is necessary for sleep. 

  • Switching off smartphones can be hard, but late-night phone calls and text messages can mean broken sleep. Achieving deep sleep is really important for a healthy brain.  Insist on the same routine for the whole family - leave phones in the kitchen before going to bed.

  • Make sure they get enough sleep. Young people need more sleep than adults – up to about nine and a half hours. This includes the time to fall asleep and be asleep. 

  • Don’t let them work late the night before the test or exam because it will be harder to do well the next day.  A brief final review which builds on earlier reviewing is far better than cramming.


  • Worst first: students should not waste time going over things they already know really well.  They could download a subject planner and prioritise the subjects/topics they find most difficult. The harder a subject or topic is, the more important it is to allow for plenty of overlearning through full use of the reviewing system.

  • Multi-sensory learning: use as many different ways as possible to make revising active and interesting.  Students may like mind maps for certain topics, index cards for others and flashcards for things like vocabulary. 

  • Focused: switch off smartphones and leave them outside the room where they are learning.  Save using any devices for the end of a complete revision session as a reward.  See the next point which can also help with focus.

  • Timed:  set a stop time for studies at home.  This should encourage focus because students know they can relax and enjoy themselves with a sense of satisfaction after a period of active, focused studying.  For example, allow for two thirty minute chunks of learning, each one followed by a five minute break and a few minutes reviewing.  Set the timer appropriately.  If half hour chunks are just too long for some students, reduce them to twenty minutes each.

As I say in the forward of my book, “Your starting point is always the reality of your child’s current attitude to learning.”  Discuss with them whether making one or two small changes to their approach will help them learn much more effectively now and in the future.


Want to find out more? Buy Elizabeth's Study Skills: Building the study skills needed for 13+ and beyond for just £12.99 here.

Study Skills 13+ can also be used alongside our 13+ revision and practice resources:

                              13+ revision resources

Tags: 13+, 13+ Common Entrance, 13+ Revision, 13, 13 plus, 13plus, revision, Revision Tips, Study, Study Skills, Studying

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