Start with deeply opposed ideological beliefs, toss in some heated red state/blue state tribal conflict, and things can quickly devolve into bad public policy. We see it on the news every day. But sometimes bad public policy stems from another cause, the hidden flaws and biases in human cognition. This is more interesting since less frequently covered. One of these cognitive flaws is what Amos Tversky and Daniel Kahneman labelled the availability heuristic, defined as “a mental shortcut that occurs when people make judgments about the probability of events by how easy it is to think of examples.” Let’s take a look at some public policies that might be improved if we understood the availability heuristic better.
First we’ll begin with some examples of the availability heuristic pulled from wikipedia.
- When a person argues that cigarette smoking is not unhealthy because his grandfather smoked three packs of cigarettes each day and lived to be 100 years old.
- Many people think that the likelihood of dying from shark attacks is greater than that of dying from being hit by falling airplane parts, when more people actually die from falling airplane parts.
At some level this all seems like no big deal. Why does it matter if readily memorable events trick our intuition, appearing likelier in our mind than in reality? Well, it matters because it means human beings have a deep and unconscious bias to overreact to flashy bad news, and under react to mundane bad news. And this can result in bad policy.
Driving Safety and Flying Safety
Airplane crashes are memorable. Automobile accidents are not. As such, the availability heuristic predicts we’ll overreact to the flashy way to die and under react to the boring way. And that turns out to be the case. Per mile traveled it’s 37x safer to fly. This is fairly well known, so I wanted to start with this one since it’s relatively non-controversial.
Nuclear Power versus Coal Power
Nukes and radiation are classic news magnets. Invisible, deadly, scary and highly memorable. Like airplane crashes. On the other hand death from fine particle air pollution is indirect and consequently boring, boring, boring. Like automobile accidents. So before I show the numbers, try to keep in mind that as human beings we’re all very strongly biased in overestimating the risks of spectacular ways to die. I’ve taken the death risks from a paper at this link, where electrical energy generation is measured in Terrawatt hours (TWh).
- Coal – 28 deaths per TWh of electrical energy
- Natural Gas – 2.8 deaths per TWh of electrical energy
- Nuclear – 0.074 deaths per TWh of electrical energy
Note that in China coal is not as clean, so the rate is worse at 77 deaths/TWh. The larger point here is not that nuclear power is perfectly safe. It’s not. And to be fair, it’s perfectly logical to be prejudiced against something that has a chance of spectacular failure. On the other hand, we have to realize generating power is risky no matter how it’s done. And relatively speaking nuclear power since 1971 is over 350x safer than coal by body count. The paper estimates that 1.8 million lives have been saved since 1971 through reduced air pollution from nuclear power. By comparison about half a million people died, even including all follow-on cancer deaths, from the World War II bombings of Hiroshima and Nagasaki. That is to say, even if we’d have had nuclear accidents as terrible as the WWII nuclear bomb bombings of Japan, we’d still have overall saved lives by having nuclear power. But of course we’ve had nothing close to that death toll. Maybe the right way to think of coal or natural gas is not to minimize the risks of nuclear power, but rather understand how air pollution is like nuclear radiation. It’s invisible and causes lung cancer. It kills people dead. Yet because radiation is far more memorable than air pollution, we’re more afraid of it despite it being historically 350x safer.
Gun Laws and Shootings
The most recent highly memorable event for guns was the December 2012 Sandy Hook shooting. From an availability heuristic point of view, Sandy Hook is the equivalent of our plane crash. On the other hand, the day to day mundane data shows that roughly 30,000 people die from gun related deaths in the US per year. Of those, 20,000 are suicide and 10,000 are homicides. Of the homicides, nearly all are from handguns. What does this mean at a policy level? If you want to go after deaths, nothing short of banning or severely restricting handguns will have an impact. Rifles, like the Bushmaster XM15-E2S rifle used at Sandy Hook, are in the noise.
Personally, I’m for this rather draconian restriction on handguns. Which I’ve written about before. But on the other hand, I know lots of people who love to hunt who strongly oppose gun control. My main takeaway on this topic is not that it’s going to get resolved, but rather framing policy around memorable rifle tragedies might not do as much as directly debating mundane handguns head on.
Terrorism and 9/11
Terrorism is almost by definition the classic case where the availability heuristic can lead people astray. It’s highly memorable and emotional. It’s rare. As a consequence it tricks the human mind into thinking it’s likely to recur, and we have to be very careful to avoid overreacting.
Let me quote from an interview with security expert Bruce Schneier done shortly after the Boston marathon bombings:
What happened in Boston, horrific as it is, is theater to make you scared. That’s the point. The message of terrorist attacks is you’re not safe, and the government can’t protect you — that the existing power structure can’t protect you.
I tell people if it’s in the news, don’t worry about it. By definition, news is something that almost never happens. The brain fools you into thinking the news is what’s important. Our brains overreact to this stuff. Terrorism just pegs the fear button.
What people should worry about are things so common that they’re no longer news. That’s what kills people. Terrorism is so rare, it’s hardly a risk worth spending a lot of time worrying about.
This seems to me exactly correct. The primary cause of death for people under 44 is accidents, like car crashes or slipping and falling. For older people it’s cancer and heart disease. If we want to make ourselves safer we have to focus on these things.
That’s not to say that terrorism should be ignored. It’s merely to say that human beings use an unconscious heuristic to identify risk. And that heuristic tends to fail for anything rare and memorable. So we have to step back and be extremely careful to avoid the temptation to overreact.
Along these lines, one of my favorite photos is the one below from Britain during the blitz in World War II. It’s the very essence of “Keep Calm and Carry On”. The fact that the photographer staged the photo by using his assistant doesn’t mar it for me very much. The blown up buildings are real, the milk and coat were borrowed from a real milkman, and the keep calm, carry on message rings true as ever. At least to me.
PS – If you are into geeky research on psychology, I highly recommend Daniel Kahneman’s bestseller Thinking Fast and Slow. It’s a concise and well written summary of the Economics Nobel Prize winner’s career researching the quirks of human cognition, including the availability heuristic.