Human Errors: A Panorama of Our Glitches, from Pointless Bones to Broken Genes

by Nathan H. Lents

If the wrist were rationally designed, it would allow the hand a full range of motion so that the fingers could bend backward and lie along the top of the arm. But of course it can’t do that. The flexibility of the wrist joint is restricted by the many bones in there, not facilitated by them.

The coccyx is the terminal part of the spinal column and consists of the last three (or four or five, depending on which you count) vertebrae fused together in a C-shaped structure. This section of bone has no function in humans. It doesn’t house or protect anything; the spinal cord, which vertebrae are designed to protect, terminates much higher than where the coccyx begins. It is vestigial—a remnant from our ancestors who had tails.

Human anatomy is beautiful, no doubt about it. We are very well adapted to our environment, but we are not perfectly adapted. Little imperfections exist. It’s possible that, if our ancestors had lived the hunter-gatherer life for a longer time before moving into the modern era of vaccines and surgery, evolution would have continued to perfect human anatomy. However, that environment, like all environments, was so dynamic that evolution would simply have substituted our current imperfections for others. Evolution is a continual process—never quite complete. Evolution and adaptation are more like running on a treadmill than running on a track: we must keep adapting in order to avoid extinction, but it can feel like we never really get anywhere.

Stop and think for a second about how ridiculous allergies are. Some people’s bodies go so crazy over a bee sting that they die. The bee stings don’t kill them; their immune systems do. Even if bee stings were truly dangerous (which they’re not), suicide still seems like an overreaction. Because of hypersensitive allergies, some people’s immune systems are like ticking time bombs. The biggest health dangers they’ll ever face in life is right inside them.

For example, all of us are frequently guilty of something called confirmation bias. This is the very human tendency to interpret information in a way that confirms what you already believe is true rather than making a fair and objective assessment. Confirmation bias can take many forms, from selective memory to errors in inductive reasoning to outright refusal to acknowledge contradictory evidence. All of these are information-processing glitches that people usually cannot see in themselves even when they are pointed out but that they find immensely frustrating in others.

The Price Is Wrong The gambler’s fallacy and the sunk-costs fallacy are two specific ways that we screw up our lives when it comes to money or other resources, but it turns out that we make even more fundamental errors when it comes to things of value: we routinely goof up the process of assigning value in the first place. Consider the games that retailers can play with price tags—and how effective their ploys are. For example, many studies have shown that consumers gravitate toward items that are marked as discounted, regardless of the actual final price. A twenty-dollar shirt will move much faster if it is priced at forty dollars and then discounted to 50 percent off. We humans measure value in relative terms, not absolute ones. We also have an anchoring bias. People give a great deal of value to the first piece of information they receive, regardless of its trustworthiness. This leads all further information to be valued not in strict terms but relative to the original. Using the example above, the first piece of information is the original (inflated) price of the shirt. This makes the sale price of twenty dollars seem much lower by comparison. The same is true in a salary negotiation or a home purchase. The first person to name a figure always sets the bar, and all of the parties in the negotiation perceive—and value—every counteroffer that follows relative to that opening bid. Savvy salary negotiators always make their first request way above what they think they will...