12/23/2015 05:41 pm ET Updated Dec 23, 2016

How Terrified Should We Be?

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After every terrorist attack we go through a period of overwhelming fear that we will individually be the target of terrorism. Recently a man told me that he will avoid going to crowded areas of the city because he fears being killed by a terrorist. A woman fears flying because she fears the plane will be blown up by a terrorist. Years ago, after 9/11, a woman told me that she feared "Arab-looking men" in the subway. And, after 9/11, years ago, a family moved to Colorado from New York City because of their fear of terrorism.

Fear pervaded the lives of many people and, once again, after the attack in San Bernardino, California where 14 people were killed, we hear about the threat of terrorism every hour of the day. If the New York Times says, "All the news that's fit to print," the 24 hour news channels should claim, "All the news that's fit to frighten". It's like living in a Nation of Fear.

What is the Real Risk?

If we look at the facts 80% of all deaths from terrorism occurred in five countries--Iraq, Afghanistan, Pakistan, Nigeria and Syria. Terrorism is comparatively a very minor risk in the United States. But that is not what you might conclude if you watch the news or follow current political discourse.

What is the real likelihood of being the victim of terrorism in the United States? Consider this-- there are about 325,000,000 people in the United States. The total number of victims of terrorism in the USA (including all kinds of terrorism) from 9/11/2001 to 12/31/2014 was 3264 of which 3003 occurred on 9/11/2014. There were 37 deaths due to terrorism in 2015. If we look at the numbers provided by the CDC for 2013 we note that there were 2,596,993 deaths in the USA. The leading causes of death were as follows:
• Heart disease: 611,105
• Cancer: 584,881
• Chronic lower respiratory diseases: 149,205
• Accidents (unintentional injuries): 130,557
• Stroke (cerebrovascular diseases): 128,978
• Alzheimer's disease: 84,767
• Diabetes: 75,578
• Influenza and Pneumonia: 56,979
• Nephritis, nephrotic syndrome, and nephrosis: 47,112
• Intentional self-harm (suicide): 41,149

How We Misperceive Risk

Since terrorism is a very unlikely event that would cause your death, why are we so frightened by it? Why aren't we panicked about the threat of heart disease, cancer, or respiratory illness? Why don't we have 24 hour news coverage of the incredible dangers of obesity, smoking, problematic diets, lack of exercise, alcoholism and other major causes of death? It may sound facetious--but it is true--you are more likely to die from a diet of cheeseburgers, bacon, fries and soda than from terrorism. Research from 2011 states that you are more likely to drown in your bathtub or be killed by a toddler than be killed by a terrorist. You are more likely to be killed by lightning than gunned down by a terrorist. Why is it that sedentary life style, not wearing a seat belt, engaging in unprotected sex (risking HIV infection)---are not major causes of fear?

Why don't we have the same frightened response?

Ten Errors in Misperceiving Risk

We have to look at how we tend to misinterpret risk. In our everyday lives we are not calculating probabilities and we are not using what statisticians call "base rates"--that is, we are not looking at the facts. How do we estimate risk, then?

When we estimate how risky something is we do not rely on objective facts as much as we should. We often use certain "rules of thumb"--or "heuristics"--that lead us to misperceive risk. These heuristics lead to greater availability of information about threat, greater importance attributed to this information, and greater tendencies for us to estimate that the threat will re-occur. In addition, we often ignore "non-events"--that is, we ignore the evidence that we are really safe and we ignore that life seems to continue much as it was yesterday. As we focus more on the threat we crowd out information that--objectively--we are quite safe.

1. Recency effects. We often place an inordinate amount of emphasis on events that have occurred recently. So, if there is a terrorist attack in the last few weeks, we tend to over-estimate the likelihood of another attack soon. As time goes by our fear declines. For example, immediately after 9/11 many of us in New York feared another attack. A year later this fear had declined considerably.
2. Recurring information. We are bombarded with stories about a threat on the news and this leads us to continually think about the threat and to view it as likely to happen again. This plays into the "availability of information"--we have constant reminders of threat.
3. Intense imagery. When we view visual images of a horrible event we tend to believe that it is more likely to occur. For example, seeing videos of carnage or of gun battles makes these events not only more memorable but also leads us to believe that they are more likely to occur. The visual images have greater emotional impact on us which adds further to our estimate of threat.
4. Malicious intention. If we believe that the agent of the threat has malicious intention then we are more likely to believe that something bad will happen. Consequently, thinking about the malicious intentions of terrorists will increase our estimate of the threat to us personally. Realistically, we should be estimating threat by using baseline information--the likelihood in the past of being killed. But we base our threat estimates on malicious intention.
5. Invisibility. If the threat is invisible--and difficult to identify--we tend to believe that we are at greater risk. For example, during the Ebola "crisis" the invisibility of the threat added to the dread that people felt about the threat. Even though the objective risk was almost zero, there was an increased estimate of the threat.
6. Lack of control. If we believe that we cannot control the threat, we believe it is more dangerous. For example, one is far more likely to die in a car accident, but we often say, "But I feel in control". Realistically, your personal control over terrorism has almost nothing to do with the likelihood of being attacked.
7. Emotional reasoning. When we are anxious we are likely to estimate the threat to be higher. It's as if we are using our emotions as a guide to how dangerous the world is. Realistically, your emotions have no relevance to the likelihood that you will be attacked.
8. This time is different. We tend to reject objective information and say, "I know that the likelihood from the past is very low. But this time is different". Of course it is possible that all the past evidence of likelihood could change with new events, but this is not the way we generally estimate danger. Consider applying for life insurance. Your insurance carrier will use actuarial tables to determine the likelihood that you will die. These are based on past history of people at your age, whether you are a smokers, and your medical history. That is how the insurance business estimates risk. They are not going to say, "Yeah, but this time it might be different".
9. I could be the one. This is a common response by people presented with the objective facts that the likelihood is low that they would be the victim of terrorism. This response discounts objective evidence and points out that it "is always possible that I could be the one". Yes, that is true--and it is true about all causes of death. But you don't go about your daily life fearing every possible risk.
10. Non-events. Can you imagine picking up the paper and the headline says, "Almost everything that happened yesterday happened the day before"? This would be the news for "non-events". Indeed, they are true events, because they actually happened. But because we do not pay attention to a plane landing safely or getting to work safely or eating food that you actually digest, we don't record these as evidence that we are safe. Our threat-oriented brains focus on possible or actual threat, not on the non-events that occur every day. Those non-events are reality.

What Should We Conclude?

An objective look at the evidence suggests that any given person is highly unlikely to be the victim of terrorism in the United States. Continual news coverage, videos of carnage, speculations about terrorist cells, dramatic memories, personal stories about how it could happen and one's fertile imagination are no substitute for the facts. Is it possible that you could be killed? Yes. Is it likely? Well, how likely are you to drown in your bathtub or be killed by lightning? It's more likely that these unusual events will strike you down. But we don't worry about them because they are incredibly unlikely. But being the victim of terrorism is even more unlikely. Our imagination is not the same thing as an objective risk.