A recent study recommends that receiving rewards as you learn can help affix new facts and skills in your memory, particularly when combined with a daytime nap.
The results suggest that memories associated with a reward are preferentially reinforced by sleep. Even a short nap can be productive.
The researcher recruited thirty-one healthy participants and they were randomly assigned to either a sleep group or a ‘wake’ group and the sensitivity of both groups to reward was examined as being equal. Participants’ brains were scanned while training them to remember pairs of pictures. Eight series of pictures were displayed and volunteers were told that remembering pairs in four of them would draw out a higher reward.
After a 90-minute break of either sleep or rest, the participants were assessed on their memory for the pairs and asked to rate how confident they were about achieving a correct response. Participants were also asked to participate in a surprise test of exactly the same nature three months later.
Both groups’ performance was improved for highly rewarded picture pairs, but the sleep group performed better overall. Considerably, during the surprise test three months later participants who had slept after learning were particularly better for the highly rewarded pairs.
The people who slept were also more confident of attempting a correct answer during the memory tests, even after three months.
The MRI scans reported that the sleep group experienced greater activity of the hippocampus, a small area of the brain important for forming memories. This corresponds with a huge number of bursts of brain activity called slow spindles. After three months, the sleep group also exhibited increased connectivity between the hippocampus, the medial prefrontal cortex and the striatum, areas of the brain involved in memory consolidation and reward processing.
The results are relevant for understanding the harsh effects that lack of sleep can have on achievement.
Contact: Kinga Igloi University of Geneva.
Details: Image source IStock