Two Views of Brain Power

The brain works hard but it doesn't always have to be that way.
July 28, 2015

You might think that your ability to reason—and all the brainpower that entails—helps you make good decisions. Reason does help, much of the time. If you face a decision about how to rebalance your retirement portfolio, for example, you should indeed list the pros and cons of different options, estimate your income sources and needs, and calculate what’s best for you. All that reasoning requires a lot of mental energy!

There are costs to applying all that brainpower to a decision, the first being time. Suppose that each time you walked into a Starbucks you looked over the menu, with its dozens of drinks, sizes, and add-ons, and then pulled out paper and pencil to begin writing down the pros and cons of different configurations. The sort of process you’d apply to your retirement planning can’t be applied to the innumerable daily decisions you face—you simply don’t have time.

Another cost is more literal: the energy consumed by your brain. If you are an average-size adult male, your brain only weighs about three or four pounds—that’s something like 2 percent of your body weight—but it uses about 20 percent of the energy expended by your body. Psychologists and neuroscientists have long known that the brain takes many shortcuts that can eliminate unnecessary processing, thus saving precious energy.

But there’s another, more pressing reason, not to apply maximum brainpower to every decision. For many decisions, trying to reason through to an optimal outcome is actually counterproductive; that is, people make worse decisions when reasoning about costs and benefits than when using simple rules, or what researchers call “heuristics.”

Four decades of research by psychologists and behavioral economists on heuristics has produced evidence supporting this claim. Heuristics are, in lay terms, shortcuts used in decision-making; phrases such as “choose what’s most familiar” or “stop searching when you find something good enough.” They use very limited information, tend to be very simple and fast, and often work better than complex reasoning.

Knowing when to use a heuristic and when to use reasoning isn’t always obvious. The most general rule—itself a heuristic!—is that reasoning works best for decisions that involve abstract, impersonal, and one-time choices, like retirement planning. Heuristics tend to work best for decisions that involve tangible personal outcomes with which you have considerable experience.

As more research accumulates, we’ll learn much more about when heuristics should be used and how to train people to use them better. That will save brainpower— and even lead to better decisions.

Huettel Ph.D. ’99 is a professor and chair of the department of psychology and neuroscience.

The capacity to experience emotion evolved to help animals, including human beings, deal quickly with events that have implications for their well-being. Negative emotions evolved to facilitate rapid responses to threats, and positive emotions evolved to manage responses to opportunities. Although we usually think of emotions as simply bad or good feelings, emotions often have great power to energize our behavior, as is apparent when we fall under the power of anger or fear or love. Emotions also have the power to determine the quality of our lives. Whether we think life is going well or badly, our judgment is essentially an assessment of the emotions we’ve experienced lately.

Emotions are, at heart, functional (and we could not survive if we lost our capacity to experience them). But two features of emotions can be maladaptive. Emotions can override rational considerations of how we should respond and lead us to behave in ways that work against our best interests. Angry outbursts, fearful inhibitions, jealous rages, or desperate actions seem at times impossible to control, as if we have been possessed by a powerful demon we are powerless to oppose.

In addition, emotions sometimes arise from our own thoughts even when nothing is objectively wrong at the moment. How many of us have tied ourselves into knots of anxiety while lying safe-and-sound in our beds, worrying about things that might never come to pass? When we work ourselves into strong emotional states through self-thought, we suffer unnecessarily at our own hands.

Although few of us are masters of all of our emotions, some people manage their emotional life more successfully than others. Recognizing that emotions must sometimes be ignored and must often be controlled is the first step. Not all emotional reactions are rational or in one’s best interests, so intelligent living requires us to manage our emotions.

Knowing that many of our emotions are evoked by our own thoughts, we can often loosen their power by changing how we think. Not only can people learn to quiet many of the thoughts that fuel their emotions, but they also can learn to think about events in ways that foster equanimity and lower the likelihood of being overtaken by emotion’s power.

Leary is the Garonzik Family Professor of psychology and neuroscience.