In our emotional repertoire each emotion plays a unique role, as revealed by their distinctive biological signatures (see Appendix A for details on "basic" emotions). With new methods to peer into the body and brain, researchers are discovering more physiological details of how each emotion prepares the body for a very different kind of response:7
• With anger blood flows to the hands, making it easier to grasp a weapon or strike at a foe; heart rate increases, and a rush of hormones such as adrenaline generates a pulse of energy strong enough for vigorous action.
• With fear blood goes to the large skeletal muscles, such as in the legs, making it easier to flee—and making the face blanch as blood is shunted away from it (creating the feeling that the blood "runs cold"). At the same time, the body freezes, if only for a moment, perhaps allowing time to gauge whether hiding might be a better reaction. Circuits in the brain's emotional centers trigger a flood of hormones that put the body on general alert, making it edgy and ready for action, and attention fixates on the threat at hand, the better to evaluate what response to make.
• Among the main biological changes in happiness is an increased activity in a brain center that inhibits negative feelings and fosters an increase in available energy, and a quieting of those that generate worrisome thought. But there is no particular shift in physiology save a quiescence, which makes the body recover more quickly from the biological arousal of upsetting emotions. This configuration offers the body a general rest, as well as readiness and enthusiasm for whatever task is at hand and for striving toward a great variety of goals.
• Love, tender feelings, and sexual satisfaction entail parasympathetic arousal—the physiological opposite of the "fight-or-flight" mobilization shared by fear and anger. The parasympathetic pattern, dubbed the "relaxation response," is a body wide set of reactions that generates a general state of calm and contentment, facilitating cooperation.
• The lifting of the eyebrows in surprise allows the taking in of a larger visual sweep and also permits more light to strike the retina. This offers more information about the unexpected event, making it easier to figure out exactly what is going on and concoct the best plan for action.
• Around the world an expression of disgust looks the same, and sends the identical message: something is offensive in taste or smell, or metaphorically so. The facial expression of disgust—the upper lip curled to the side as the nose wrinkles slightly—suggests a primordial attempt, as Darwin observed, to close the nostrils against a noxious odor or to spit out a poisonous food.
• A main function for sadness is to help adjust to a significant loss, such as the death of someone close or a major disappointment. Sadness brings a drop in energy and enthusiasm for life's activities, particularly diversions and pleasures, and, as it deepens and approaches depression, slows the body's metabolism. This introspective withdrawal creates the opportunity to mourn a loss or frustrated hope, grasp its consequences for one's life, and, as energy returns, plan new beginnings. This loss of energy may well have kept saddened—and vulnerable—early humans close to home, where they were safer.
These biological propensities to act are shaped further by our life experience and our culture. For instance, universally the loss of a loved one elicits sadness and grief. But how we show our grieving—how emotions are displayed or held back for private moments—is molded by culture, as are which particular people in our lives fall into the category of "loved ones" to be mourned.
The protracted period of evolution when these emotional responses were hammered into shape was certainly a harsher reality than most humans endured as a species after the dawn of recorded history. It was a time when few infants survived to childhood and few adults to thirty years, when predators could strike at any moment, when the vagaries of droughts and floods meant the difference between starvation and survival. But with the coming of agriculture and even the most rudimentary human societies, the odds for survival began to change dramatically. In the last ten thousand years, when these advances took hold throughout the world, the ferocious pressures that had held the human population in check eased steadily.
Those same pressures had made our emotional responses so valuable for survival; as they waned, so did the goodness of fit of parts of our emotional repertoire. While in the ancient past a hair-trigger anger may have offered a crucial edge for survival, the availability of automatic weaponry to thirteen-year-olds has made it too often a disastrous reaction.8
Our Two Minds
A friend was telling me about her divorce, a painful separation. Her husband had fallen in love with a younger woman at work, and suddenly announced he was leaving to live with the other woman. Months of bitter wrangling over house, money, and custody of the children followed. Now, some months later, she was saying that her independence was appealing to her, that she was happy to be on her own. "I just don't think about him anymore—I really don't care," she said. But as she said it, her eyes momentarily welled up with tears.
That moment of teary eyes could easily pass unnoted. But the empathic understanding that someone's watering eyes means she is sad despite her words to the contrary is an act of comprehending just as surely as is distilling meaning from words on a printed page. One is an act of the emotional mind, the other of the rational mind. In a very real sense we have two minds, one that thinks and one that feels.
These two fundamentally different ways of knowing interact to construct our mental life. One, the rational mind, is the mode of comprehension we are typically conscious of: more prominent in awareness, thoughtful, able to ponder and reflect. But alongside that there is another system of knowing: impulsive and powerful, if sometimes illogical—the emotional mind. (For a more detailed description of the characteristics of the emotional mind, see Appendix B.)
The emotional/rational dichotomy approximates the folk (distinction between "heart" and "head"; knowing something is right "in your heart" is a different order of conviction—somehow a deeper kind of certainty—than thinking so with your rational mind. There is a steady gradient in the ratio of rational-to-emotional control over the mind; the more intense the feeling, the more dominant the emotional mind becomes—and the more ineffectual the rational. This is an arrangement that seems to stem from eons of evolutionary advantage to having emotions and intuitions guide our instantaneous response in situations where our lives are in peril—and where pausing to think over what to do could cost us our lives.
These two minds, the emotional and the rational, operate in tight harmony for the most part, intertwining their very different ways of knowing to guide us through the world. Ordinarily there is a balance between emotional and rational minds, with emotion feeding into and informing the operations of the rational mind, and the rational mind refining and sometimes vetoing the inputs of the emotions. Still, the emotional and rational minds are semi-independent faculties, each, as we shall see, reflecting the operation of distinct, but interconnected, circuitry in the brain.
In many or most moments these minds are exquisitely coordinated; feelings are essential to thought, thought to feeling. But when passions surge the balance tips: it is the emotional mind that captures the upper hand, swamping the rational mind. The sixteenth-century humanist Erasmus of Rotterdam wrote in a satirical vein of this perennial tension between reason and emotion:9