Jan 29, JDN 2457783

Since the 1990s, crime in United States has been decreasing, and yet in every poll since then most Americans report that they believe that crime is increasing.

It’s not a small decrease either. The US murder rate is down to the lowest it has been in a century. There are now a smaller absolute number (by 34 log points) of violent crimes per year in the US than there were 20 years ago, despite a significant increase in total population (19 log points—and the magic of log points is that, yes, the rate has decreased by precisely 53 log points).

It isn’t geographically uniform, of course; some states have improved much more than others, and a few states (such as New Mexico) have actually gotten worse.

The 1990s were a peak of violent crime, so one might say that we are just regressing to the mean. (Even that would be enough to make it baffling that people think crime is increasing.) But in fact overall crime in the US is now the lowest it has been since the 1970s, and still decreasing.

Indeed, this decrease has been underestimated, because we are now much better about reporting and investigating crimes than we used to be (which may also be part of why they are decreasing, come to think of it). If you compare against surveys of people who say they have been personally victimized, we’re looking at a decline in violent crime rates of two thirds—109 log points.

Just since 2008 violent crime has decreased by 26% (30 log points)—but of course we all know that Obama is “soft on crime” because he thinks cops shouldn’t be allowed to just shoot Black kids for no reason.

And yet, over 60% of Americans believe that overall crime in the US has increased in the last 10 years (though only 38% think it has increased in their own community!). These figures are actually down from 2010, when 66% thought crime was increasing nationally and 49% thought it was increasing in their local area.

The proportion of people who think crime is increasing does seem to decrease as crime rates decrease—but it still remains alarmingly high. If people were half as rational as most economists seem to believe, the proportion of people who think crime is increasing should drop to basically zero whenever crime rates decrease, since that’s a really basic fact about the world that you can just go look up on the Web in a couple of minutes. There’s no deep ambiguity, not even much “rational ignorance” given the low cost of getting correct answers. People just don’t bother to check, or don’t feel they need to.
What’s going on? How can crime fall to half what it was 20 years ago and yet almost two-thirds of people think it’s actually increasing?

Well, one hint is that news coverage of crime doesn’t follow the same pattern as actual crime.

News coverage in general is a terrible source of information, not simply because news organizations can be biased, make glaring mistakes, and sometimes outright lie—but actually for a much more fundamental reason: Even a perfect news channel, qua news channel, would report what is surprising—and what is surprising is, by definition, improbable. (Indeed, there is a formal mathematical concept in probability theory called surprisal that is simply the logarithm of 1 over the probability.) Even assuming that news coverage reports only the truth, the probability of seeing something on the news isn’t proportional to the probability of the event occurring—it’s more likely proportional to the entropy, which is probability times surprisal.

Now, if humans were optimal information processing engines, that would be just fine, actually; reporting events proportional to their entropy is actually a very efficient mechanism for delivering information (optimal, under certain types of constraints), provided that you can then process the information back into probabilities afterward.

But of course, humans aren’t optimal information processing engines. We don’t recompute the probabilities from the given entropy; instead we use the availability heuristic, by which we simply use the number of times we can think of something happening as our estimate of the probability of that event occurring. If you see more murders on TV news than you used you, you assume that murders must be more common than they used to be. (And when I put it like that, it really doesn’t sound so unreasonable, does it? Intuitively the availability heuristic seems to make sense—which is part of why it’s so insidious.)

Another likely reason for the discrepancy between perception and reality is nostalgia. People almost always have a more positive view of the past than it deserves, particularly when referring to their own childhoods. Indeed, I’m quite certain that a major reason why people think the world was much better when they were kids was that their parents didn’t tell them what was going on. And of course I’m fine with that; you don’t need to burden 4-year-olds with stories of war and poverty and terrorism. I just wish people would realize that they were being protected from the harsh reality of the world, instead of thinking that their little bubble of childhood innocence was a genuinely much safer world than the one we live in today.

Then take that nostalgia and combine it with the availability heuristic and the wall-to-wall TV news coverage of anything bad that happens—and almost nothing good that happens, certainly not if it’s actually important. I’ve seen bizarre fluff pieces about puppies, but never anything about how world hunger is plummeting or air quality is dramatically improved or cars are much safer. That’s the one thing I will say about financial news; at least they report it when unemployment is down and the stock market is up. (Though most Americans, especially most Republicans, still seem really confused on those points as well….) They will attribute it to anything from sunspots to the will of Neptune, but at least they do report good news when it happens. It’s no wonder that people are always convinced that the world is getting more dangerous even as it gets safer and safer.

The real question is what we do about it—how do we get people to understand even these basic facts about the world? I still believe in democracy, but when I see just how painfully ignorant so many people are of such basic facts, I understand why some people don’t. The point of democracy is to represent everyone’s interests—but we also end up representing everyone’s beliefs, and sometimes people’s beliefs just don’t line up with reality. The only way forward I can see is to find a way to make people’s beliefs better align with reality… but even that isn’t so much a strategy as an objective. What do I say to someone who thinks that crime is increasing, beyond showing them the FBI data that clearly indicates otherwise? When someone is willing to override all evidence with what they feel in their heart to be true, what are the rest of us supposed to do?