New research by U.K. scientists finds that even short naps may help people better weigh the pros and cons of a difficult decision. Investigators measured changes in people’s brain activity and responses before and after a nap and found that delaying a decision until after one “sleeps on it” is sound advice.
In the study, University of Bristol researchers sought to understand whether a short period of sleep can help us process unconscious information and how this might affect behavior and reaction time. Their findings appear in the Journal of Sleep Research.
Investigators discovered the benefits of a short bout of sleep on cognitive brain function and found that even during short bouts of sleep we process information that we are not consciously aware of.
Although previous studies have confirmed that sleep helps problem solving – resulting in enhanced cognition upon awaking – it was not clear whether some form of conscious mental process is required before or during sleep to aid problem solving.
In this study, researchers hid information by presenting it very briefly and “masking” it. This means that the information was never consciously perceived, a technique called the masked prime task.
The hidden information, however, was processed at a subliminal level within the brain and the extent to which it interferes with responses to consciously perceived information was measured.
Sixteen healthy participants across a range of ages were recruited to take part in an experiment. Participants carried out two tasks: the masked prime task, and a control task where participants simply responded when they saw a red or blue square on a screen. Participants practiced the tasks and then either stayed awake or took a 90-minute nap before doing the tasks again.
Using an electroencephalograph (EEG) the electrical activity naturally produced in the brain was recorded. From this the researchers measured the change in brain activity and response pre-and-post nap.
Sleep (but not wake) improved processing speed in the masked prime task but not in the control task, suggesting sleep-specific improvements in processing of subconsciously presented primes.
The finding that information acquired during wakefulness may potentially be processed in some deeper, qualitative way during sleep may be used to optimize human goal-directed behavior.
Dr. Liz Coulthard, consultant senior lecturer in dementia neurology at the University of Bristol Medical School, said, “The findings are remarkable in that they can occur in the absence of initial intentional, conscious awareness, by processing of implicitly presented cues beneath participants’ conscious awareness.
“Further research in a larger sample size is needed to compare if and how the findings differ between ages, and investigation of underlying neural mechanisms.”
Source: University of Bristol/EurekAlert