Farnam Street helps you make better decisions, innovate, and avoid stupidity.

With over 400,000 monthly readers and more than 93,000 subscribers to our popular weekly digest, we've become an online intellectual hub.

When The Human Body Needs Randomness

I picked up a copy of The New Evolution Diet for two reasons. First, the book contains an afterword by Nassim Taleb. Second, the book’s author, Art De Vany, happens to be an economist and I’ve never seen a diet book written by an economist before.

I thought you’d find this passage as interesting as I did.

According to chaos theory, certain systems that seem to be random in fact are not–it’s just difficult for us to perceive, at the outset, all the subtle factors that set the course and determine the outcome. …

Another scientific concept, the power law, also comes up often in my discussions of health and fitness. It is based on the Pareto principle, named for Italian economist Vilfredo Pareto. In essence, it describes the relationship between how common a factor is and how much influence it exerts. It says that the most unusual events will have the greatest impact. Pareto’s study determined that 80 percent of privately held land in Italy was owned by 20 percent of the population. Similar power laws exist all around us.

For instance, in my study of the movie business, I learned that 90 percent of the profits come from 10 percent of the movies. And for directors, 40 percent of their lifetime revenues come from a single film. Scientists have found that 40 percent of a decade’s damage due to flood will come from just one such event. The Richter law of earthquakes says that the most common quakes are small, and the rare big ones do nearly all the damage. This relationship between low frequency and high impact is found again and again, in various fields of science, business, and elsewhere.

… There is a power law of exercise, too: Your least frequent most extreme exertions will have the greatest influence on your fitness. The peak moments of a workout count far more than the amount of time you spend working out. This is why a series of 40-yard sprints at full speed benefits you more than a half an hour of jogging. It’s also the reason why lifting a weight heavy enough to make your heart pound your muscles burn counts more than spending hours at the gym always in your comfort zone, never truly challenging your body. When a workout becomes an unvarying, monotonous routine, it loses its effectiveness.

Power law teaches us that the average can be meaningless and even misleading. In the movie business, many films lose money, and a few are huge hits. But if you compute the average box office receipts, you may be fooled into thinking that all films earn money — which is far from the case. In fact, it is likely that no firm earned anything like the average sum.

… Ancient hunter-gatherers spent much of their time doing little or nothing. And then, every so often, they took action that would exhaust any 21st-century gym rat. Overall, they burned twice as much energy as we do. Lions sleep most of the time, but then they make up for it by chasing down, killing, and carrying away an adult gazelle. The lion doesn’t try to maintain a steady output of moderate energy. It has no need to do so.