The short answer is “yes.” If you’re going to take an IQ test, make sure you get a full night’s sleep several days before the test to ensure you’re well rested. Before outlining what we know from recent research, I’ll share a personal story.
One year, during my undergraduate studies in mathematics and physics, I fell behind in my preparation for the final examinations. The final grade in each of these demanding courses was determined entirely by a 3-hour problem solving marathon. To compensate for my profligate preparation, I pulled several “all-nighters,” getting just a few hours sleep for 3 consecutive nights. On the way home from the last examination, I replayed in my mind, the solutions I had submitted to various problems. To my horror, I realized that I had made significant errors in simple computations, yielding incorrect results. When someone asked me the name of the course for which I had just written the exam, I had great difficulty retrieving it. I learned from experience that when the brain is starved for sleep, the memory is much depleted and problem solving skills are impaired. This is not a good mental condition for writing an exam in quantum physics or for taking an IQ test.
In a recent study, Matt Walker, one of the world’s foremost researcher’s on sleep and the effects of sleep deprivation conducted a control experiment in which a group of people who had a full 8 hours sleep were tested against a group who had been deprived of sleep the night before. Both groups were given information to learn and were tested on their recall. The sleep-deprived group retained only 60% of what the control group retained. In other words, sleep deprivation reduces our ability to learn and retain new information. (See an excellent YouTube video featuring Dr. Walker at: Sleep is your superpower )
What happens to your IQ if you go through long periods of sleep deprivation? MRI scans that reveal brain activity show active energy impulses in the brain during periods of deep sleep. It is believed that these episodes enable to brain to “file away” daily learning into long-term storage for later retrieval. The accumulation of daily learnings builds, over months and years, a reservoir of information that we call “crystallized intelligence” that contributes to our IQ.
A round of rapid and extensive production of neurons and synapses followed by extensive neural pruning, occurs as a person enters puberty, significantly modifying and restructuring the neural network Throughout this development, we might expect that a person’s IQ would remain relatively stable, because IQ is a measure of intelligence relative to others of the same age. However, recent research indicates that while the average IQ of those in the same age cohort is relatively stable over a span of several years, the IQ of an individual can change significantly during this period. In a longitudinal study, 33 teenagers of average age 14.1 years were administered an IQ test and a structural brain scan in 2004 and then again in 2007, when their average age was 17.7 years. It was found that during this period, the average IQ of the group had changed very little; however about 20% of the participants showed a positive or negative change in IQ of at least 15 points (one standard deviation). Furthermore, magnetic resonance imaging (MRI) revealed that positive changes in IQ corresponded to increased gray matter in sections of the brain associated with those cognitive functions. Summarizing their findings, the researchers reported:
Our results emphasize the possibility that an individual’s intellectual capacity relative to their peers can decrease or increase in the teenage years. This would be encouraging to those whose intellectual potential may improve, and would be a warning that early achievers may not maintain their potential.
A full night’s sleep, especially throughout these formative years, is vital for building brain power and enhancing IQ. Even into adulthood getting adequate sleep is vital for brain health, and it is believed that sufficient sleep delays the onset of dementia.
