The human brain is arguably evolution’s greatest accomplishment. Give credit to your brain for language, learning, memory, comprehension, reasoning, judgment, perception and countless other cognitive abilities.

Our brains make us sentient beings. We are aware of our awareness. By age 3 the human toddler, due to brain development, has begun to develop the ability to reflect on its own activity and in time will be able to control its own thinking and behavior to accomplish self established goals. Remarkable, even miraculous!

So, if we are so brainy and sophisticated, why do we repeatedly make bad decisions? Why do we engage in war, rape the earth for its resources, categorize others by superficial differences, hoard wealth as others starve and blindly follow a leader to a destructive end? The answers to these questions are, of course, impossibly elusive. While capable of incredible achievements, research in cognitive psychology reveals that our brains are by no means perfect. Thinking errors by the brain can create havoc and we are all subject to them. Let’s examine just a few of many.

A common error is confirmation bias. We selectively attend to information that supports an attitude or belief we hold while ignoring evidence that refutes our attitude. Our perception of the world is skewed by our brain to match our beliefs. If I believe a particular ethnic group is miserly and money seeking, I will selectively notice supporting examples and thus harden my attitude.

Confirmation bias helps us explain the current debate about crime and illegal immigration on the southern border. The individual who believes illegal immigrants from Central America and Mexico commit a high volume of violent crime will perceive examples of such crime while ignoring the peaceful, productive behavior of this population. Research reported in the journal Criminology actually reveals decreasing rates of violent crime in geographical areas with an increasing population of undocumented immigrants.

Another error, called belief in small numbers, works with confirmation bias to further harden attitudes. How often we jump to conclusions based on a limited sample size. Again let us take the issue of crime and illegal immigration. Recently a police officer in California was shot to death by an illegal immigrant. Our brains are willing to conclude that based on this single incident we are at risk of being the victim of violent crime by the immigrant population. Our brains should know better. A single case is insufficient evidence to draw a valid conclusion. In fact, the rate of violent crime is lower in the immigrant population than for the nonimmigrant population.

Sports fans often erroneously “play the percentages” and lose as a result. This mental error is known as the gambler’s fallacy. I believe I can predict a player’s present performance based on whether he is meeting his historical standard. When a batter hitting .300 is hitless in his three previous at bats, I know my player is “due” for a hit. I fail to understand that each at bat is an independent event that is not influenced in some magical way by past performance. How dangerous when an investor predicts that the price of soybeans will rise because the past three summers have been moist and mild indicating that a hot and dry summer, bad for soybeans, is overdue.

Consider a thinking error known as the availability heuristic. Our brains easily recall information and experiences that are novel, that stand out, that elicit an emotional response and that convey personal meaning. Everyone of age remembers 9/11. Not only do we recall attention-grabbing events, but we also overestimate their presence or frequency. If two gigantic tank trucks full of fuel collide, explode, burn and destroy a neighborhood in a spectacular scene, we are likely to overestimate the likelihood that this event will be repeated. The horror of a terrorist attack causes us to predict that an attack is more likely to occur than it actually is, even when there is no specific support for this prediction.

The consequences of thinking errors run from minor errors in judgment to costly, even catastrophic outcomes. Effects can be limited to an individual or be felt by an entire society. What are we to do with our flawed brains and the errors they produce? As a first step, teaching children and adolescents in the school setting to identify thinking errors and how to avoid them is recommended. Formally imbedding discussion of thinking errors into such classes as current events, history, literature, and public speaking seems important. In higher education classes in psychology and philosophy are ideal for expanding the discussion to greater depth. We all benefit by recognizing the errors committed by our brains and exercising damage control.


John Seaman

John Seaman, Ph.D., is a retired school psychologist and a retired adjunct professor of psychology at Salt Lake Community College.