Why Zebras Don’t Get Ulcers


In his book Why Zebras Don’t Get Ulcers; 3rd ed., 2004), Stanford biology and neurology professor Robert Sapolsky discusses (often humorously) stress, stress-related disease, and coping with stress. But, first: “Why ‘Don’t’ Zebras Get Ulcers”? The answer is the difference between acute physical stress(ors), chronic physical stress(ors), and psychological and social disruptions. Regarding those first two ways to get upset, Sapolsky writes:

“Think like a zebra for a second….(A) lion has just leapt out and ripped your stomach open, you’ve managed to get away, and now you have to spend the next hour evading the lion as it continues to stalk you. Or, perhaps just as stressfully, you are that lion, half-starved, and you had better be able to sprint across the savanna at top speed and grab something to eat or you won’t survive….Your body’s responses are brilliantly adapted for handling this sort of emergency….(Or, humanly-speaking) The locusts have eaten your crops, and for the next six months, you have to wander a dozen miles a day to get enough food. Drought, famine, parasites…not the sort of experience we have often, but central events in the lives of non-westernized humans and most other mammals. The body’s stress-responses are reasonably good at handling these sustained disasters.” (p. 4)

Which brings us to Sapolsky’s third way to get upset: “psychological and social disruptions.” He writes:

“Regardless of how poorly we are getting along with a family member or how incensed we are about losing a parking spot, we rarely settle that sort of thing with a fistfight. Likewise, it is a rare event when we have to stalk and personally wrestle down our dinner. Essentially, we humans live well enough and long enough, and are smart enough, to generate all sorts of stressful events purely in our heads.” (pp. 4-5)

Ah, the culprit: Our heads! I knew it! Fortunately, Sapolsky discusses several, key “research” principles that can help our heads get out of the way (pp. 255-270). Those stress-reducing, research principles (which you know would have to include some rat experiments) are as follows:

– Outlets for Frustration – For example, a rat receives a series of mild electric shocks. The rat develops the potential for an ulcer. A different rat gets the same series of shocks, but is given a piece of food to gnaw on (or,something to eat, drink, or maybe a running wheel). The potential for developing an ulcer is significantly reduced –  because it has been given an outlet for frustration. Hmmm.

– Social Support – Substitute rats with primates. Put a primate through something unpleasant and it becomes stressed. Put that primate through the same stressor while in a room of other primates and – well, two different responses. If the other primates are strangers, stress goes up; if friends, stress goes down. Point? Social connectedness helps modulate stress(ors).

– Predictability – Back to rats. A rat gets a series of mild, electric shocks, but hears a warning bell before each shock. Result? Fewer ulcers, because predictability makes stress(ors) less stressful. Why? When the bell sounds, at least the rat knows what’s coming and can relax the rest of the time. In therapy, I am constantly asking clients to audit their predictability in a given situation; for example, deciding who/what is not in their control, and what is in their control. Because anxiety implies unpredictability, an increase in predictability can reduce anxiety. Obviously, there are caveats; for example, when predictability means boredom, or something positively bad. But, in general, more predictability = less anxiety.

– Control – Control is closely related to predictability. A rat is given a series of mild shocks, but has been trained to press a lever to avoid the shocks. Take away the lever, and stress goes up. Return the lever to the rat, and stress goes down – even if the lever is disconnected from the shock mechanism. In other words, even the “perception” of control can reduce stress-responses. Obviously, some of the same caveats that apply to predictability apply to control, including a comment I often make to clients. I ask them to think of a controlling person (which they usually can do, sometimes implicating themselves); then, tell them – that person is also an anxious person because “control” is how anxious people go about reducing their anxiety.

– A Perception of Things Improving – Two rats get a series of electric shocks. The first day, one rat gets 10 shocks an hour; another rat gets 50 shocks an hour. The second day, both rats get 25 shocks an hour. Which rat’s stress-responses improve? Obviously, the second rat who’s thinking (in Sapolsky’s words): “Twenty-five? Piece of cheese.” (p. 263) In other words, if we perceive things are improving–even slightly–so much the better.

Bill Bray, Colorado Springs, CO

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