In the wake of the 14 terrorism-inspired murders in San Bernardino on December 2, 2015, and other recent terror attacks, some Americans altered their travel plans. They were worried about their personal safety.

A survey found that about 10% of American travelers canceled a planned trip, causing a potential loss of about $8.2 billion in travel-related spending. Another 18% changed their destination to one that was perceived to be safer, while another 25% delayed travel. In other words, recent terrorist attacks led about 53% of American travelers to change their behavior.

That raised the obvious question: Why?

Based on how the human mind sees the world and applies logic or common sense to what it believes it sees, changing travel plans makes intuitive or subjective sense, if reducing even a vanishingly small risk is the goal. Calibrating responses to all risks according to their statistical likelihood is reasonably defined as rational.

Assuming that is the definition of how to rationally respond to threats, changing travel plans due to a terrorist attack is not rational.

A recently reported study of American public opinion revealed that most adult Americans believed that they had about a 30% chance of personally facing a threat of terrorist violence within the next 12 months. Based on numbers of deaths from terrorist attacks in the U.S., the actual, statistical risk is far lower.

Over a 5-year period (2008-2013), the chance of an American civilian dying due to a terrorist attack anywhere, including Iraq and Afghanistan, was about 1 in 20 million. For context, the chance of a civilian death in a 1-year period from fireworks was about 1 in 50 million, about 1 in 11 million for a dog attack or lightning strike and about 1 in 25,000 for a non-terrorist gunshot.

The Fear and Anger Biases

Clearly, changing travel plans makes no objective sense, but many people do it anyway.

Researchers found two main emotional responses to terrorist attacks, fear in women and anger in men. Those emotions tended to shape people’s opinions -- including policymakers. Those two emotions tended to simplify thinking about risk behavior and policy preferences. Fear tends to increase perceptions of personal risk, while anger tends to decrease risk perception and to increase aggressiveness.

One of the researchers who studied people's reactions to terror attacks found that people usually believe that their policy preferences are tightly linked to their core values or ideological beliefs. Depending on personal values or beliefs, “emotionally evocative” information (e.g., information that generates fear or anger) can break or distort that linkage.

Detrimental impacts of emotion-based biases on thinking and actions can be reduced by simply recognizing that fear and anger change how we see and think about the world. Simply discussing emotion-charged issues with other people is helpful as well. Also, getting enough sleep reduces emotion-based biases. Being tired exacerbates unconscious fear and anger biases.

Perceptions of reality and thinking about it is a mostly unconscious intuitive-emotional activity. For better or worse, the unconscious human mind rarely applies statistics to real-world situations. The rational or analytical mind has its own limitations: “It weakens when the physical body is tired, it’s lazy, and it, too, has problems with statistical thinking.”

Due to our biology, intuition or emotion dominates thinking and risk perception. That is why 53% of American travelers recently changed their travel plans in response to a trivial risk. A conscious effort and some training is needed to inject reason based on statistical information.

Because the “rational mind” is easily tired and lazy, applying reason to real world situations and issues requires motivation and discipline. That is something sorely lacking in most of our policymakers.

Travelers vs. Political Leaders

As for personal choices and travel plans, irrational responses to overblown threats have small consequences. The travel industry takes an economic hit and peoples’ vacations get changed.

By contrast, when policymakers let their emotions irrationally drive their thinking and choices, the consequences can be stunningly expensive and lethal, but mostly or completely unnecessary.

The question for everyone is obvious: What kind of thinking and risk assessment is best for the American people and/or the rest of world, 100% emotional-irrational, 100% objective-rational, or a mix of the two (e.g., 10:90, 30:70, 50:50, 70:30 or 90:10)?

That question isn’t nearly as easy to answer as it may seem.