Nurture Shock, by Po Bronson and Ashley Merryman, earns frequent comparisons to Freakonomics, the bestselling book that surveyed scientific research and applied the findings to everyday questions. Nurture Shock does something similar, but focuses on child development.
Chapter Two of Nurture Shock makes the connection between rising rates of childhood obesity, anxiety, and attention disorders and the latest brain science on the value of sleep. We now understand, for example, that sleep is essential to learning, because what is learned during the day is filed in appropriate parts of the brain while we sleep. When children get too little sleep, their ability to retain new information declines.
This affects not only factual memories, but emotional memories as well. Too little sleep reduces a child’s ability to remember positive experiences, which are stored in a different part of the brain than negative experiences. Thus, children who get too little sleep experience more depression and anxiety.
Everywhere I go, adults talk about the number of children that take meds for anxiety. We assume that parents and doctors are too quick to prescribe, and perhaps they are, but it’s also possible that young people really experience more anxiety than their parents’ generation. According to Nurture Shock, “It is an overlooked fact that children – from elementary school through high school – get an hour less sleep each night than they did thirty years ago.” The reasons for this change are as many and as varied as the households in which young people are losing sleep. But the impact is stunning.
Bronson and Merryman’s analysis of the research reveals that sleep deprivation impairs not only academic performance and emotional stability, but also “phenomena that we assumed to be entirely unrelated, such as the international obesity epidemic and the rise of ADHD.”
The findings on obesity provide a good example of why this book gets compared to Freakonomics. Conventional wisdom attributes the obesity epidemic to television and video games, claiming that young people gain weight because of their sedentary lifestyles. This “fact” seems logical and self-evident, so people assume it is true. But the research tells a different story, because in study after study, normal weight and overweight children spend the same amount of time in sedentary activities. They watch the same amount of television and play video games just as much.
A stark difference between the two groups is the amount of sleep they get. “All of the studies point in the same direction: on average, children who sleep less are fatter than children who sleep more.” It turns out that “slow-wave” sleep, which constitutes 40% of a child’s sleep time, is especially critical to proper insulin sensitivity and glucose tolerance. Adequate sleep may be more important than nutrition education in reducing obesity.
The research on sleep matters for adults, too. Studies show that getting too little sleep each night produces a cumulative effect, degrading one’s reflexes and judgment. Business people often prize bravado over boring old common sense, averring, “I’ll sleep when I’m dead.” More likely, we’ll make important decisions while we’re brain-dead.
Normally I read an entire book before I recommend it, but by the time I finished the second chapter of Nurture Shock, I knew I had to spread the word. This is a thought-provoking book, and heaven knows, we need more thinking out there. But to do your best thinking, get a good night’s sleep.