Here’s a story for you. Harold Hartley is a sales representative for a Detroit steel company. Every Monday, he catches the disastrously early 5:45am Northwest Airlines flight to Indianapolis to work with a major client there. Every Thursday, after three and a half long days of hard selling, he topples into his coach class seat on the 1:26pm back to his family in Detroit.
He’s been doing this for years; has it down to a routine. He goes to the airport with a tiny rolling bag and nothing in his pockets, wearing slip-on shoes so he can get through security in under 3 minutes.
One day, an account manager Harold sees every week misses an appointment about modifying some large orders. Harold waits at his office for half an hour, an hour, two hours—he never shows up. A few minutes into the third hour, the secretary approaches Harold, eyes wide, to tell him that the manager has been in a plane crash.
Shaken, Harold takes an overnight bus back to Detroit and never flies again.
A couple of months later, Harold is driving home from Indianapolis late at night after closing a difficult but successful deal. A few miles outside of Albion, MI on Interstate 94, a drunk driver heading home from the bar tries to change lanes and smashes into Harold’s car at 50mph. Both cars are totaled and Harold is rushed to the hospital.
According to transportation safety statistics, by switching to the car for his weekly trip to Indianapolis, Harold had dramatically increased his chance of injury and doubled his chance of death in a transportation accident.
This story, while fictional, is completely plausible. Even more plausible, and extremely common, is the situation where people skip out on something—eating raw-fish sushi, for example—because we’re anxious about a bad consequence that is actually vanishingly unlikely.
Harold’s mistake is called the availability heuristic. The availability heuristic is a mental bias that makes us feel that something is more likely the more easily we can recall or imagine an example of it. It makes us massively overestimate the likelihood of very improbable events if we have a vivid, recent example of that event, often from a movie or the news.
Psychologists Tversky and Kahneman described the availability heuristic in a famous paper in Science called “Judgment under Uncertainty: Heuristics and Biases”; Kahneman later won the Nobel Prize in Economics, despite being a psychologist with no economics training. The books Nudge and The Science of Fear talk about this universal mental quirk from different fascinating angles.
A couple things that might help with those skewed anxieties and prevent us from doing a Harold Hartley: comparing the actual probability of an event with something else that is concrete and easily imaginable (e.g.: “If I eat 20,000 eggs, only one of them is likely to have salmonella bacteria”) or flooding yourself with lots of examples of the danger you’re worried about NOT happening (e.g.: “My uncle is an airline pilot who spends 20 hours a week flying, and he’s never even had a single scare”).
Our pal Harold’s name, in case you’re wondering, came from a random name generator based on U.S. Census data.