The Art Of Choosing: The Decisions We Make Everyday of our Lives, What They Say About Us and How We Can Improve Them

by Sheena Iyengar

Such responses are survival-enhancing for short-term situations in the wild because they motivate an animal to terminate the source of stress and regain control. But when the source of stress is unending—that is, when it can’t be fled or fought—the body continues its stressed response until it is exhausted. Animals in a zoo still experience anxiety over basic survival needs and the possibility of predator attacks because they don’t know that they’re safe. Physically, remaining in a constant state of heightened alert can induce a weakened immune system, ulcers, and even heart problems. Mentally, this stress can cause a variety of repetitive and sometimes self-destructive behaviors known as stereotypies, the animal equivalent of wringing one’s hands or biting one’s lip, which are considered a sign of depression or anxiety by most biologists.