There is a classic experiment in psychology in which a participant is seated in front of two bowls, one filled with chocolate chip cookies and one with radishes. Half the participants in the experiment are told to eat what they wish -- and almost all, naturally, eat cookies. Half are told that they may eat radishes but not cookies -- and, naturally, most eat very few. When told the experiment is over, each participant is escorted to another room and asked to complete a complex puzzle. Those who have eaten chocolate chip cookies stay with the task longer. Those who were told to eat only radishes give up much sooner. The explanation: concentrating on NOT eating cookies takes mental energy, and so less is available for the complex task. In psycho-lingo, this is called ego depletion. The prefrontal cortex, which sits just behind the forehead, is hard at work when concentrating on a mental task (like NOT eating cookies). While it makes up only 4-5 percent of brain volume, it consumes a great deal more of the body's energy when pressed into service. So, when that energy is depleted, the brain is literally too tired to function at its mental best.
This may sound cute but not critical. Yet it has implications for citizens in a free society. Democracy depends on us thinking about matters that concern us. As Jefferson put it: "We may tolerate error, as long as reason is free to combat it." But what if reason is not available? What if our brains are too energy-starved to think clearly about our common concerns?
This problem is not new, of course. But as the amount, speed and complexity of information have mushroomed, the problem has gotten worse. Some estimates suggest that the amount of data in the world doubles every two years. It comes at us 24/7, via Web, cell, computer, satellite and cable as well as in print. We do not seem able (or want) to turn it off. The data are also more complex, taxing our understanding as well as our energy. Just pick any topic -- radishes, for example, where you can acquire 165,000 search engine results alone on the health benefits of radishes.
But public affairs -- data, discussion, and decisions about who we are, how we live, what we value, what policies and programs will benefit (our harm) us, and who should speak for us in our representative democracy -- is a harder subject than radishes. What if we are just too mentally tired to think well about these complex things?
The brain has a coping strategy for such situations. It applies mental heuristics -- simple routines that take no conscious thought. Some of these routines are essential and work out quite well -- such as driving to work every day, a complex task that we can carry out with little mental energy. But mental heuristics can get us in trouble when they present routines that do not square with the actual world. Stereotypes about people, parties, and politicians are examples where short-circuiting our thinking saves us mental energy. We assume things about others by the group they belong to, but those stereotypes often do grave injustice to those cast in little boxes that match neither their intent, actions, nor capabilities.
There is a way out of this problem. It is called diversity. Surrounding ourselves with those who have different views offers a counterweight to our own mental exhaustion and errors. Unfortunately, we seem to be eliminating the diversity we need. We go to websites that reflect our existing views. We associate with friends who share similar ideas. We live in neighborhoods of people "like us." We participate in politics only with people who we know are "right." We watch cable news only from channels whose hosts we agree with. We discount contrasting views as biased because they come from people and groups we do not know and do not trust.
The danger and irony for all of us -- liberal and conservative, secular and evangelical, wealthy, middle class, and poor alike -- is that just as the world gives us the information to make more informed and reasoned decisions about our joint fate, we are so overwhelmed that we cannot take advantage of the opportunity.
There is no simple solution to this conundrum. But it would be a start if we would recognize that we often employ simplistic mental strategies to deal with our own mental exhaustion, and that we are endangering democracy by doing so.