Cover; Mysteries of the Mind; Scientific American Presents; by Staff Editor; 1 Page(s)

From the Editors; Mysteries of the Mind; Scientific American Presents; by Rennie; 1 Page(s)

Master detective Hercule Poirot, the hero of many an Agatha Christie novel, boasted repeatedly about the power of "the little gray cells" in his head to solve the toughest mysteries. For philosophers, writers and other thinkers, however, those little gray cells have been the greatest mystery of all. How do a couple of pounds of spongy, electrically active tissue give rise to a psychological essence? How do we emerge from the neural thicket?

Empirical scientists may be relative newcomers to this investigation (unlike the philosophers, they've been on the case for only a few hundred years), but they have taken long strides forward in that short time. In this special issue of Scientific American, some of the leading researchers in neuroscience and in psychology discuss how much is now known about the nature of consciousness, memory, emotions, creativity, dreams and other mental phenomena. Their answers suggest that some of these mysteries may be largely solved within our lifetimes--even if new ones are posed in the process.

Table of Contents; Mysteries of the Mind; Scientific American Presents; by Staff Editor; 2 Page(s)

The Mind-Body Interaction in Disease; Mysteries of the Mind; Scientific American Presents; by Sternberg, Gold; 8 Page(s)

The belief that the mind plays an important role in physical illness goes back to the earliest days of medicine. From the time of the ancient Greeks to the beginning of the 20th century, it was generally accepted by both physician and patient that the mind can affect the course of illness, and it seemed natural to apply this concept in medical treatments of disease. After the discovery of antibiotics, a new assumption arose that treatment of infectious or inflammatory disease requires only the elimination of the foreign organism or agent that triggers the illness. In the rush to discover new antibiotics and drugs that cure specific infections and diseases, the fact that the body's own responses can influence susceptibility to disease and its course was largely ignored by medical researchers.

It is ironic that research into infectious and inflammatory disease first led 20th-century medicine to reject the idea that the mind influences physical illness, and now research in the same field-including the work of our laboratory and of our collaborators at the National Institutes of Health-is proving the contrary. New molecular and pharmacological tools have made it possible for us to identify the intricate network that exists between the immune system and the brain, a network that allows the two systems to signal each other continuously and rapidly. Chemicals produced by immune cells signal the brain, and the brain in turn sends chemical signals to restrain the immune system. These same chemical signals also affect behavior and the response to stress. Disruption of this communication network in any way, whether inherited or through drugs, toxic substances or surgery, exacerbates the diseases that these systems guard against: infectious, inflammatory, autoimmune and associated mood disorders.

The Problem of Consciousness; Mysteries of the Mind; Scientific American Presents; by Francis Crick and Christof Koch; 9 Page(s)

The overwhelming question in neurobiology today is the relation between the mind and the brain. Everyone agrees that what we know as mind is closely related to certain aspects of the behavior of the brain, not to the heart, as Aristotle thought. Its most mysterious aspect is consciousness or awareness, which can take many forms, from the experience of pain to self-consciousness. In the past the mind (or soul) was often regarded, as it was by Descartes, as something immaterial, separate from the brain but interacting with it in some way. A few neuroscientists, such as Sir John Eccles, still assert that the soul is distinct from the body. But most neuroscientists now believe that all aspects of mind, including its most puzzling attribute-consciousness or awareness-are likely to be explainable in a more materialistic way as the behavior of large sets of interacting neurons. As William James, the father of American psychology, said a century ago, consciousness is not a thing but a process.

Exactly what the process is, however, has yet to be discovered. For many years after James penned The Principles of Psychology, consciousness was a taboo concept in American psychology because of the dominance of the behaviorist movement. With the advent of cognitive science in the mid-1950s, it became possible once more for psychologists to consider mental processes as opposed to merely observing behavior. In spite of these changes, until recently most cognitive scientists ignored consciousness, as did almost all neuroscientists. The problem was felt to be either purely "philosophical" or too elusive to study experimentally. It would not have been easy for a neuroscientist to get a grant just to study consciousness.

The Puzzle of Conscious Experience; Mysteries of the Mind; Scientific American Presents; by Chalmers; 7 Page(s)

Conscious experience is at once the most familiar thing in the world and the most mysterious. There is nothing we know about more directly than consciousness, but it is extraordinarily hard to reconcile it with everything else we know. Why does it exist? What does it do? How could it possibly arise from neural processes in the brain? These questions are among the most intriguing in all of science.

From an objective viewpoint, the brain is relatively comprehensible. When you look at this page, there is a whir of processing: photons strike your retina, electrical signals are passed up your optic nerve and between different areas of your brain, and eventually you might respond with a smile, a perplexed frown or a remark. But there is also a subjective aspect. When you look at the page, you are conscious of it, directly experiencing the images and words as part of your private, mental life. You have vivid impressions of the colors and shapes of the images. At the same time, you may be feeling some emotions and forming some thoughts. Together such experiences make up consciousness: the subjective, inner life of the mind.

The Pursuit of Happiness; Mysteries of the Mind; Scientific American Presents; by Myers, Diener; 3 Page(s)

Compared with misery, happiness is relatively unexplored terrain for social scientists. Between 1967 and 1994, 46,380 articles indexed in Psychological Abstracts mentioned depression, 36,851 anxiety, and 5,099 anger. Only 2,389 articles spoke of happiness, 2,340 life satisfaction, and 405 joy.

Recently we and other researchers have begun a systematic study of happiness. During the past two decades, dozens of investigators throughout the world have asked several hundred thousand representatively sampled people to reflect on their happiness and satisfaction with life-or what psychologists call "subjective well-being." In the U.S. the National Opinion Research Center at the University of Chicago has surveyed a representative sample of roughly 1,500 people a year since 1957; the Institute for Social Research at the University of Michigan has carried out similar studies on a less regular basis, as has the Gallup Organization. Government-funded efforts have also probed the moods of European citizens.

Manic-Depressive Illness and Creativity; Mysteries of the Mind; Scientific American Presents; by Jamison; 6 Page(s)

"Men have called me mad," wrote Edgar Allan Poe, "but the question is not yet settled, whether madness is or is not the loftiest intelligence--whether much that is glorious--whether all that is profound--does not spring from disease of thought--from moods of mind exalted at the expense of the general intellect."

Many people have long shared Poe's suspicion that genius and insanity are entwined. Indeed, history holds countless examples of "that fine madness." Scores of influential 18th- and 19th-century poets, notably William Blake, Lord Byron and Alfred, Lord Tennyson, wrote about the extreme mood swings they endured. Modern American poets John Berryman, Randall Jarrell, Robert Lowell, Sylvia Plath, Theodore Roethke, Delmore Schwartz and Anne Sexton were all hospitalized for either mania or depression during their lives. And many painters and composers, among them Vincent van Gogh, Georgia O'Keeffe, Charles Mingus and Robert Schumann, have been similarly afflicted.

Depression's Double Standard; Mysteries of the Mind; Scientific American Presents; by Leutwyler; 2 Page(s)

Mental health workers have long noticed a preponderance of women among the clinically depressed. Until recently, though, it was unclear whether more women than men were ill or, instead, whether more women sought help. In fact, a mounting collection of studies has confirmed that major depression is twice as common among women as it is among men. "This is one of the most consistent findings we have ever had," says Myrna M. Weissman of Columbia University. Women also seem more susceptible to milder melancholia and to seasonal affective disorder (SAD).

Scientists searching for explanations are challenged by the fact that a variety of cues prompt depression in different people. Sorting out which factors might have a greater influence on women has not proved easy. Both sexes stand an equal chance of inheriting major depression, so genes are most likely not to blame. Yet hormones and sleep cycles-which differ dramatically between the sexes-can alter mood. Also, many workers have proposed that social discrimination might put women under high levels of stress, thereby doubly disposing them to major depressive disorder.

The Meaning of Dreams; Mysteries of the Mind; Scientific American Presents; by Winson; 8 Page(s)

Throughout history human beings have sought to understand the meaning of dreams. The ancient Egyptians believed dreams possessed oracular power-in the Bible, for example, Joseph's elucidation of Pharaoh's dream averted seven years of famine. Other cultures have interpreted dreams as inspirational, curative or alternative reality. During the past century, scientists have offered conflicting psychological and neuroscientific explanations for dreams. In 1900, with the publication of The Interpretation of Dreams, Sigmund Freud proposed that dreams were the "royal road" to the unconscious; that they revealed in disguised form the deepest elements of an individual's inner life.

More recently, in contrast, dreams have been characterized as meaningless, the result of random nerve cell activity. Dreaming has also been viewed as the means by which the brain rids itself of unnecessary information-a process of "reverse learning," or unlearning.

Emotion, Memory and the Brain; Mysteries of the Mind; Scientific American Presents; by LeDoux; 8 Page(s)

Despite millennia of preoccupation with every facet of human emotion, we are still far from explaining in a rigorous physiological sense this part of our mental experience. Neuroscientists have, in modern times, been especially concerned with the neural basis of such cognitive processes as perception and memory. They have for the most part ignored the brain's role in emotion. Yet in recent years, interest in this mysterious mental terrain has surged. Catalyzed by breakthroughs in understanding the neural basis of cognition and by an increasingly sophisticated knowledge of the anatomical organization and physiology of the brain, investigators have begun to tackle the problem of emotion.

One quite rewarding area of research has been the inquiry into the relation between memory and emotion. Much of this examination has involved studies of one particular emotion-fear-and the manner in which specific events or stimuli come, through individual learning experiences, to evoke this state. Scientists, myself included, have been able to determine the way in which the brain shapes how we form memories about this basic, but significant, emotional event. We call this process "emotional memory."

The Neurobiology of Fear; Mysteries of the Mind; Scientific American Presents; by Kalin; 8 Page(s)

Over the years, most people acquire a repertoire of skills for coping with a range of frightening situations. They will attempt to placate a vexed teacher or boss and will shout and run when chased by a mugger. Some individuals, though, become overwhelmed in circumstances others would consider only minimally stressful: fear of ridicule might cause them to shake uncontrollably when called on to speak in a group, or terror of strangers might lead them to hide at home, unable to work or shop for groceries. Why do certain people fall prey to excessive fear?

At the University of Wisconsin at Madison, my colleague Steven E. Shelton and I are addressing this problem by identifying specific brain processes that regulate fear and its associated behaviors. Despite the availability of noninvasive imaging techniques, such information is still extremely difficult to obtain in humans. Hence, we have turned our attention to another primate, the rhesus monkey (Macaca mulatta). These animals undergo many of the same physiological and psychological developmental stages that humans do, but in a more compressed time span. As we gain more insight into the nature and operation of neural circuits that modulate fear in monkeys, it should be possible to pinpoint the brain processes that cause inordinate anxiety in people and to devise new therapies to counteract it.

Phantom Limbs; Mysteries of the Mind; Scientific American Presents; by Melzack; 7 Page(s)

In 1866 S. Weir Mitchell, the foremost American neurologist of his time, published his first account of phantom limbs, not in a scientific journal but in the Atlantic Monthly, as an anonymously written short story. In his tale, "The Case of George Dedlow," the protagonist loses an arm to amputation during the Civil War. Later, he awakens in the hospital after, unbeknownst to him, both his legs have also been amputated.

"[I was] suddenly aware of a sharp cramp in my left leg. I tried to get at it... with my single arm, but, finding myself too weak, hailed an attendant. 'Just rub my left calf,... if you please.'" "'Calf?. ..You ain't got none, pardner. It's took off.'"

Autism; Mysteries of the Mind; Scientific American Presents; by Frith; 7 Page(s)

The image often invoked to describe autism is that of a beautiful child imprisoned in a glass shell. For decades, many parents have clung to this view, hoping that one day a means might be found to break the invisible barrier. Cures have been proclaimed, but not one of them has been backed by evidence. The shell remains intact. Perhaps the time has come for the whole image to be shattered. Then at last we might be able to catch a glimpse of what the minds of autistic individuals are truly like.

Psychological and physiological research has shown that autistic people are not living in rich inner worlds but instead are victims of a biological defect that makes their minds very different from those of normal individuals. Happily, however, autistic people are not beyond the reach of emotional contact and attachment to others.

Seeking the Criminal Element; Mysteries of the Mind; Scientific American Presents; by Gibbs; 8 Page(s)

"Imagine you are the father of an eight-year-old boy," says psychologist Adrian Raine, explaining where he believes his 17 years of research on the biological basis of crime is leading. "The ethical dilemma is this: I could say to you, 'Well, we have taken a wide variety of measurements, and we can predict with 80 percent accuracy that your son is going to become seriously violent within 20 years. We can offer you a series of biological, social and cognitive intervention programs that will greatly reduce the chance of his becoming a violent offender.' What do you do? Do you place your boy in those programs and risk stigmatizing him as a violent criminal even though there is a real possibility that he is innocent? Or do you say no to the treatment and run an 80 percent chance that your child will grow up to (a) destroy his life, (b) destroy your life, (c) destroy the lives of his brothers and sisters and, most important, (d) destroy the lives of the innocent victims who suffer at his hands?"

For now, such a choice is purely hypothetical. Scientists cannot yet predict which children will become dangerously aggressive with anything like 80 percent accuracy. But increasingly, those who study the causes of criminal and violent behavior are looking beyond broad demographic characteristics such as age, race and income level to factors in individuals' personality, history, environment and physiology that seem to put them-and society-at risk. As sociologists reap the benefits of rigorous long-term studies and neuroscientists tug at the tangled web of relations between behavior and brain chemistry, many are optimistic that science will identify markers of maleficence. "This research might not pay off for 10 years, but in 10 years it might revolutionize our criminal justice system," asserts Roger D. Masters, a political scientist at Dartmouth College.