Mad cows and irrational humans

Human beings are irrational in how they handle risk. Irrational reactions or poor information about risky choices result in our society being less well off than if we managed risk better.

The way we seem to be reacting to news of “mad cow disease” is a good example: We may well increase — rather than reduce — deaths resulting from bad food. Understanding our own irrationality in the face of apparent danger may help improve how we respond as a society.

Another recent example of how humans deal with risk: “I had control most of the way down.” I’m sure I wasn’t the only person to smile at that assertion by the Minnesota teen who plunged down a mountain on his snowmobile. His comment illustrated one facet of human response to risk. It is psychologically very important for us to feel that we have some element of control over their lives even when that control is limited or illusory.

That human thirst for control in an uncertain world leads people to irrational behavior in the face of risk. We accept very risky situations when we think we are in control and avoid much less risky ones when everything appears out of our grasp.

Auto vs. air travel is an example. One is several times more likely to get killed per mile traveled by car than by airplane. The disparity of risk of non-fatal injury is even greater. Yet many people who fear airplane travel think nothing of getting into a car even on days when ice or fog multiplies the normal dangers of auto travel. This asymmetry in how we view risk. We often are killed or injured because of this asymmetry.

Another way we are irrational in the face of risk involves how familiar the risk is. We tend to be blasé about familiar risks, but pull back sharply from unfamiliar ones. Familiarity really does breed contempt when humans face dangerous situations. We drive the old beater with failing brakes, plug in the frayed extension cord, skip buckling the recalcitrant seat belt because we are just going to the store anyway, or continue to wolf down steaks even when our cholesterol level is three times our I.Q.

These factors — rejecting risk when there is no element of control and preferring known risks to unfamiliar ones — enter into public reaction to the recent discovery of one U.S. cow with Bovine Spongiform Encephalopathy or “mad cow disease.”

The chance of any single person dying as a result of eating BSE-contaminated beef is infinitesimal. Most such deaths occurred in the United Kingdom in the 1990s. From the first case in the 1980s until now, about 150 people have died of variant Creutzfeldt-Jakob disease, the human malady caused by BSE. The U.K. has a population of 60 million people. Here in the United States, some 100 people per week die of food-borne illnesses, and many more are sickened. This does not mean that our food supply is grossly unsafe. In a population of 300 million, about 10,000 persons die each day from all causes. Food-borne illnesses other than variant Creutzfeldt-Jakob are only a minor factor in mortality.

Creutzfeldt-Jakob in humans and BSE in cattle do occur spontaneously from time to time for reasons not well understood. In the U.K., the disease clearly was spread to many cattle through feed containing cooked byproducts from dead cattle or cattle slaughterhouses. This practice was more than a century old and is described in books such as Upton Sinclair’s “The Jungle” and the pleasant memoirs of British veterinarian James Herriot.

For decades, scientists though that any pathogens were destroyed in the rendering process. They were wrong, but were proved wrong only by the discovery of a previously unknown biological entity called a prion, which is significantly different from common bacteria and viruses.

The important thing is that the risk of death from BSE-contaminated meat is extremely low. Yet we worry about it because it is new and because there seems to be nothing any individual can do to control the risk. BSE-contaminated meat does not look, taste or smell bad. One cannot avoid it by staying away from certain restaurants that receive poor ratings from the health department. In fact, you don’t even know you have the disease until years after eating the contaminated meat.

Eating virtually any cut of beef today involves less danger than driving to work, but millions of people apparently have reduced their beef consumption. Ironically, many may have switched to chicken, which while quite safe, is the meat that most commonly causes food poisoning. We discount the threat of salmonella, E. coli and campylobacter because these pathogens are familiar.

Epidemiologists such as Minnesota’s Mike Osterholm long have argued correctly that we spend too much money on dramatic, high-tech medical interventions and not nearly enough on basic public health. We would save more lives if we spent less on surgeries and devices and more on food inspection and testing or if we simply were willing to allocate more tax dollars to our health departments.

One response to the BSE scare may be implementation of a national system to identify and track individual cows over their entire lives. Such a system might cost up to $1 billion or so to set up and another $100 million to $300 million to operate each year. Ask the average citizen if it is a good idea to spend $3 per capita right now and another $1 per capita per year afterward for a measure that might reduce the risk of mad cow disease. The vote will be overwhelmingly in favor.

Ask health economists and epidemiologists to list the 10 best ways to reduce premature death or improve health with the same amount of resources, and I am quite sure that reducing BSE via a cow tracking system won’t appear on many such lists.

This is a good example of how bad information combined with inherent human irrationality makes us worse off than we might be. The more resources we expend on reducing BSE, the more people will continue to die of non-BSE related problems. This may seem a cruel irony, but it is very human.

© 2004 Edward Lotterman
Chanarambie Consulting, Inc.