Quotes from Randolph M. Nesse

Chlamydia, today´s most common cause of venereal disease, does the equivalent of hiding in the police station. Schistosomes of the mansoni type go a step further and essentially steal police uniforms. These parasites, a serious cause of liver disease in Asia, pick up blood-group antigens so that they may look to the immune system like our own normal blood cells.

The mechanisms our minds use to anticipate the results of our actions are inadequate for coping with modern media.

Darwinism gives no moral guidelines about how we should live or how doctors should practice medicine. A Darwinian perspective on medicine can, however, help us to understand the evolutionary origins of disease, and this knowledge will prove profoundly useful in achieving the legitimate goals of medicine.

First, the rest of medicine recognizes symptoms, such as pain and cough, as protective defenses and carefully distinguishes them from the disorders that arouse them. In psychiatry, by contrast, extremes of emotions, such as anxiety and low mood, are categorized as disorders, irrespective of any situation that might be arousing them. This error is so basic and pervasive that it deserves a name: Viewing Symptoms As Diseases (VSAD).

Internal medicine doctors know the functions of the kidneys. They don't confuse protective defenses such as cough and pain with diseases such as pneumonia and cancer. Psychiatrists lack a similar framework for the utility of stress, sleep, anxiety, and mood, so psychiatric diagnostic categories remain confusing and crude.

The greatest boon of modern life is also the greatest villain: the availability of plentiful food.30,31,32,33,34,35 Or, rather, foodlike substances manufacturers concoct with the exact combinations of sugar, salt, and fat that we most desire.

The body is not shaped for maximum health or longevity; it is shaped for maximum transmission of its genes. Alleles (different versions of a gene) that increase the number of offspring become more common over the generations, even if that shortens life and increases suffering. This is not merely theoretical. Half of the human population has been shaped by selection to live fast and die young.

In the clinic it is obvious that what patients believe about human nature influences their lives and problems.

The German psychologist Jutta Heckhausen, now in California, studied a group of childless middle-aged women who were still hoping to have a baby. As they approached menopause, their emotional distress became more and more intense. But after menopause those who gave up their hope for pregnancy lost their depression symptoms.81 The irony is deep: hope is often at the root of depression.

Mood allocates] investments of time, effort, resources, and risk taking to maximize Darwinian fitness in situations of varying propitiousness. High and low moods adjust cognition and behavior to cope with propitious and unpropitious situations.

Caffeine seems innocuous, but a single coffee bean can kill a mouse.

Just as the capacity for experiencing fatigue has evolved to protect us from overexertion, the capacity for sadness may have evolved to prevent additional losses. Maladaptive extremes of anxiety, sadness, and other emotions make more sense when we understand their evolutionary origins and normal, adaptive functions.

Emotional capacities are shaped by situations that occurred repeatedly in the course of evolution and that were important to fitness. Attacks by predators, threats of exclusion from the group, and opportunities for mating were frequent and important enough to have shaped special patterns of preparedness, such as panic, social fear, and sexual arousal. Situations that are best avoided shape aversive emotions, while situations that involve opportunity shape positive emotions.

Paradoxically, it now is much easier to treat many mental disorders than it is to understand them.

Just as there are several components of the immune system, each of which protects us against particular kinds of invasions, there are subtypes of emotion that protect us against a variety of particular kinds of threats.

Therapists have long known that may depressions go away only after a person finally gives up some long-sought goal and turns his or her energies in another direction.

Therapists have long known that many depressions go away only after a person finally gives up some long-sought goal and turns his or her energies in another direction.

People are not controlled by some internal calculator that crudely motivates them to maximize their reproductive success. Instead, people form deep, lifelong emotional attachments and experience loves and hates that shape their lives. They have religious beliefs that guide their behavior, and they have idiosyncratic goals and ambitions. They have networks of friends and relatives.

I can't prove it, but I'm pretty sure that people gain a selective advantage from believing in things they can't prove.