More evidence that sleep improves memory has been logged into research archives.
As part of highly technical research designed to map the connection between various parts of the human brain and memory, British scientists have confirmed findings by other researchers that sleep has a positive effect on retention and recall.
An investigative team led by Dr. P.A. Lewis of the School of Psychological Sciences at England’s University of Manchester exposed two groups of volunteers to a series of photographic images. Immediately afterward, the groups were tested and no significant difference was found between them in ability to recall important details of what they had seen.
One group was tested in the morning and then kept awake for the next 12 hours. The other, tested in the evening, was allowed to sleep through the night.
Subsequent re-testing then revealed that the group that slept remembered more. “[M]emory decays less across an…interval containing sleep than across an equivalent interval of…wakefulness,” the researchers report. In short, sleep appears to reduce the amount of forgetting that takes place, at least short-term.
Scans by the researchers via functional magnetic resonance imaging (fMRI) suggest that the brain’s hippocampus and superior parietal cortex are involved in the role of sleep’s “consolidation” and “stabilization” of “newly encoded memories.”
“This study adds to the growing body of well-documented knowledge that supports letting involved officers rest before taking their statements after a shooting or other high-intensity event,” says Dr. Bill Lewinski, executive director of the Force Science Institute.
“In this study there was no difference between the amount of recall immediately after the exposure to test images and 12 hours later—provided the subjects were able to sleep. Otherwise there was significant deterioration.
“Given that the ability of officers to accurately and fully report on critical incidents is crucial, this study suggests that if we allow officers time for emotional decompression and rest to the point where they are ready for what might be the most important interview of their life and also employ techniques for facilitating recall, such as a walk through, we won’t lose anything in regards to the quantity and quality of information they are able to provide.
“Other more comprehensive studies strongly support the role of memory consolidation through sleep to the point where memory is actually enhanced after sleep.”
A detailed report on the British study appears in the journal Neuropsychologia. You can read an abstract of the findings free of charge by clicking here.
[Our thanks to Cst. Dave Blocksidge of the London Metropolitan Police for alerting us to this study.]