Sleeping in between study sessions could be the key to better recall, new research finds.
The technique aids recall up to six months later, psychologists have found.
Dr Stephanie Mazza, the study’s first author, said:
“Our results suggest that interleaving sleep between practice sessions leads to a twofold advantage, reducing the time spent relearning and ensuring a much better long-term retention than practice alone.
Previous research suggested that sleeping after learning is definitely a good strategy, but now we show that sleeping between two learning sessions greatly improves such a strategy.”
The study compared groups that were learning new words in Swahili.
Half did two learning sessions on one day: in the morning and evening.
The other half did the sessions either side of sleeping: evening and then the next morning.
The results showed that sleeping in between learning sessions allowed people to learn the words quicker and with less effort.
Dr Mazza said:
“Memories that were not explicitly accessible at the beginning of relearning appeared to have been transformed by sleep in some way.
Such transformation allowed subjects to re-encode information faster and to save time during the relearning session.”
Sleeping in between learning had boosted memory by about 50%, when both groups were tested a week later.
The effect was even still noticeable when participants were followed up after six months.
How sleep enhances learning
Sleep after learning encourages brain cells to make connections with other brain cells, recent research has shown.
The connections, called dendritic spines, enable the flow of information across the synapses.
The findings, published in the prestigious journal Science, were the first to show physical changes in the motor cortex resulting from learning and sleep.
The new study was published in the journal Psychological Science (Mazza et al., 2016).