Animal Die-Offs, Mass Shootings, and the Power of Random

In today’s Los Angeles Times, Skeptic editor Michael Shermer brings some sanity to coverage of both the shootings in Tuscon and the well-reported fish and bird deaths around the country:

We live in a causal universe, so all effects do have causes, but before we turn to grand, overarching causal theories such as political rhetoric or government experiments, we must always remember the clustering effect of randomness and how our brains tend to look for and find meaningful patterns even where none exist… [O]ur brains abhor randomness and seek meaning. 

The National Institute of Mental Health estimates that about 1% of the population suffers from schizophrenia, and that more than 25% of us have some kind of diagnosable mental disorder. This means that about 3 million people with psychosis are walking among us, as well as tens of millions more whose mental health is askew in some way. And many of those who need treatment aren’t receiving it. Given these statistics, events such as the shooting in Tucson are bound to happen, no matter how nicely politicians talk to one another on the campaign trail or in Congress, no matter how extreme tea party slogans are about killing government programs, and no matter how stiff or loose gun control laws are in this or that state. By chance — and nothing more — there will always be people who do the unthinkable.

According to National Audubon Society biologist Melanie Driscoll, about 5 billion birds die each year in the United States from a variety of causes. Because of the clustering effect of randomness, it is inevitable that some of those billions of birds will die in apparent non-random clusters. The 5,000 red-winged blackbirds that died in Arkansas, for example, looks like an ominous cluster when scattered about the ground, but there are more than 200 million red-winged blackbirds in the United Sates, and, according to Driscoll, they fly in flocks of 100,000 to 2 million. Although 5,000 birds falling dead out of the sky sounds positively apocalyptic, it represents a scant .000025% of the total population.