by Adam Lee on May 30, 2008

Given that this is an atheist site, I feel compelled to start this post with a snappy anti-religion quip, so here it is: Children and teenagers are more likely to be molested or assaulted in church than they are on social networking sites like MySpace. Parents, do you want to protect your kids? Keep them home on Sundays and send them to the computer instead!

But it wouldn’t be fair to leave it at that. This statistic doesn’t prove the inherent riskiness of going to church. What it proves is that most crimes – against both children and adults – are committed by someone the victim knows personally, not by a random stranger. The idea of pedophiles and kidnappers trolling the Internet and snatching up unsuspecting children is lurid, shocking, sensational, which is why it captures the imagination. But the reality is that such things are so extremely rare as to be essentially not worth worrying about.

The truth is, as many reporters have documented, that human beings are not good at rationally assessing risk. This post will list some of the more common ways in which our risk judgments go awry.

People overestimate the odds of spectacular, attention-grabbing catastrophes, while underestimating the danger posed by common, everyday risks. The paradigm example of this is the common phobia of flying – stemming, no doubt, from news reports of spectacular plane crashes – while hardly any people have a similar fear of driving, which is by almost any measure a more dangerous activity. Another good example is the widespread fear of terrorist attack, although the total number of people ever wounded or killed by terrorism is far less than the number of victims of “ordinary” dangers such as domestic violence.

Our brains rapidly habituate to familiar situations, and risks that we encounter daily soon become part of the background patterns we’re accustomed to. But shocking, unlikely events disrupt that expectation and leave a vivid, emotional stamp on our memories. As a result, these risks are more salient and are often judged to be more likely, even when nothing could be farther from the truth.

People overestimate risks they cannot control and underestimate risks they can. Again, driving vs. flying is a common example. Even sitting in the passenger seat of someone else’s car, as opposed to driving yourself, may make the oncoming traffic appear much faster. When we feel we are not in control of the situation, the danger seems greater than when we believe we are in control.

People underestimate risks that creep up over time. As in the first point, the brain habituates to risks that are encountered often, until they scarcely seem dangerous at all. But this tendency can turn fatal when the slow, gradual accumulation of risk ultimately results in a deadly situation – like the metaphorical frog that will jump out of a pot of scalding water but can be boiled to death by turning the heat up slowly. Both on the personal level, with lifestyle diseases such as atherosclerosis or smoking, and societal dangers such as global warming, humans are often reluctant to confront problems that haven’t seemed to do any harm so far.

People underestimate risks for which there is a perceived benefit. Risk assessments are almost impossible to divorce from perceived benefits and values, and when a person sees “something in it for them”, the accompanying risks will seem less serious. Conversely, the risk seems greater for activities that have no perceived upside. One of the earlier linked articles has an example: while dozens of teenagers are killed each year from sports-related injuries, no one is harmed by marijuana use. Yet sports is thought of as less dangerous because society perceives that it instills positive character traits, while no such benefit related to recreational drug use is envisioned.

People overestimate “artificial” risks and underestimate “natural” risks. Although “natural” substances can be just as poisonous as “artificial” chemicals, or even more so (think of deadly nightshade or hemlock), people tend to prefer the former to the latter. Psychology Today adds:

Our built-in bias for the natural led a California town to choose a toxic poison made from chrysanthemums over a milder artificial chemical to fight mosquitoes: People felt more comfortable with a plant-based product.

…When a case report suggested that lavender and tea-tree oil products caused abnormal breast development in boys, the media shrugged and activists were silent. If these had been artificial chemicals, there likely would have been calls for a ban, but because they are natural plant products, no outrage resulted.

A more telling example is the pseudoscientific hysteria over microwaves from cell phone towers or power lines allegedly causing cancer, when every day we are bathed in far more dangerous and legitimately carcinogenic radiation – from the Sun.

Other posts in this series: