Introduction

The great memory scientist Hermann Ebbinghaus (1850–1909) is often quoted as saying that psychology has a long past but a short history. Humans have indeed thought about many of the ideas and practices that we now call psychology for a very long time. For about the last 150 years, there has been an effort to develop the scientific study of those ideas. In addition to science, modern psychology is also a profession, with many practices designed to help people live better lives and cope with the demands of contemporary society. This duality of psychology makes it a rich and rewarding subject that reaches into every aspect of our lives today.

The Scope of Psychology

Psychologists study topics that are of great interest and usefulness in everyday life, such as children’s development, decision making, work, sleep, aging, health, and many other topics. Psychologists have also developed a variety of theories about the functioning of the mind, from Sigmund Freud’s energy model to the computer model of Nobel Prize winner Herbert Simon. Therapies designed to help people cope with psychological problems have become an important part of psychologists’ work as well.

Modern psychological science and practices developed most rapidly in Europe and North America, but the roots of both science and practice can be found throughout recorded history. As will become apparent in this book, thoughtful people from a variety of times and places have contributed to our understanding of ourselves. For thousands of years, psychological principles were closely linked to religion, philosophy, medicine, and other systems of thought, including astrology and astronomy. In every civilization there have been people who wrote about the human spirit, about mind and behavior, and tried to understand disorders of the mind. People who were not educated or even literate popularized systems of thought linked to the body, such as palmistry, physiognomy, and phrenology, as a way to understand themselves and others.

The Psychology Book is about psychological ideas over the centuries and the people behind those ideas. Both human and animal psychology have fascinated some of the world’s great thinkers, and we will explore what they have said and written about them. For example, the American philosopher and psychologist William James once wrote to a friend that “psychology is a damnable subject, and all that one may wish to know lies entirely outside it.” James wrote this out of exasperation after spending twelve years writing The Principles of Psychology (1890), which is considered one of the greatest books in the field. Clearly, James did not reject psychology; in fact, he continued to make significant contributions until his death in 1910. His comment may best be understood as reflecting the complexity of psychology. How can we ever understand something as varied as human thought and behavior?

Indeed, psychology is one of the most complex of all scientific and professional fields. It often appears at first glance to be just a matter of common sense, its truths intuitively accessible, or a matter of common folk knowledge. Yet as we look closer, we see that what appeared on the surface to be common sense is actually a science, rich in knowledge, nuance, and subtlety. An example from cognitive psychology may serve as an illustration. In the 1970s, Israeli psychologists Daniel Kahneman and Amos Tversky wondered what might lead people to make decisions that were not rational or in their best interest. They found that when a person has to make a decision in a condition of uncertainty—for example, when asked whether more people die in plane crashes or automobile accidents—he or she may rely on a mental shortcut, or heuristic, to aid in making the decision. These shortcuts may be based on the ease with which an example comes to mind—the availability heuristic—or on the assumption of similarity where none exists, commonly called the representativeness heuristic. Kahneman and Tversky showed that human beings are not always rational—and perhaps not even primarily so—in making decisions. Of course, Sigmund Freud had argued that humans are not creatures of reason almost a century before Kahneman and Tversky, although he based his arguments on very different evidence. In The Psychology Book, we will encounter many questions about rationality, emotionality, and their important consequences.

What about the multitude of human behaviors that are important not only for our personal survival but also for the survival of our species? Freud, as you may know, wrote extensively about human sexuality. He claimed that the most basic motivation in life is sex, and that our personalities are shaped very early in life by how we resolve the tensions between pleasure and the dictates of society. Before and after Freud, people have theorized about the place of sex in human life and how to understand the powerful sexual urges that most humans feel. In some societies, sexuality is celebrated and open, while in others it is a taboo topic. Recently, evolutionary psychologists have theorized that the template for male-female sexual attraction is based in our ancient evolutionary past. Other psychologists argue that sexual attraction is socially constructed and that what we see as desirable is shaped by the environment in which we live.

In today’s world, one of the most frequently asked questions concerns our personalities. What kind of person am I? How can I understand myself better so that I can be more successful in relationships, work, and other domains of life? Human beings have sought answers to these and other questions for millennia. In ancient Mesopotamia, Egypt, and medieval Islamic countries, people created the signs of the zodiac in an attempt to understand themselves and others. Palmistry and numerology are also ancient strategies for understanding, predicting, and controlling human behavior. In fact, the human body has often been used as a way for people to understand themselves. Physiognomy sought to understand human character by the shape of one’s face, and phrenology offered explanations of character and abilities based on the shape and protrusions of the human skull. Similar body-based theories have continued to our own day, with such well-respected developmental psychologists as Jerome Kagan and Nathan Fox claiming that there are typical body differences between shy and non-shy children. In the twentieth century, psychologists developed other approaches that were based on responses to surveys and questionnaires. This allowed for statistical manipulation of the respondents’ data and resulted in an apparently more scientific approach to personality theory. Older theories, such as those of Sigmund Freud and Carl Jung, however, have retained great appeal for millions of people around the world. We will explore several landmark theories of human personality in The Psychology Book.

The rich variety of human experience described in the following pages is intellectually exciting and stimulating. We will note the important discoveries and theories in many areas of psychology. Since the science of psychology connects with almost every other domain of life on this planet, it will be difficult to touch on all of those connections, but you will find interesting, important, and sometimes humorous milestones here. People’s thoughts about human relationships, from love to sex to friendship to hate, are all represented in the book. So, too, are important contributions to understanding human development from the womb to the tomb. Work life is an important domain for each of us, and psychologists have made many important contributions to its understanding. Personality and mental health and illness are often linked, and we will see what key contributions have been made in these related areas. In the last two decades, happiness has become an object of research, especially within the Positive Psychology movement, and we will see how this current topic is linked to past ideas. Psychology also encompasses brain science. Since the mid-nineteenth century, scientists have made tremendous advances in understanding how the brain shapes behavior and, conversely, how the brain is changed by our experience. Inventions and technology have been used by neuroscientists to explain basic psychological processes such as memory formation and to explain how psychotropic medications act to relieve depression and anxiety. In other words, our topic is large, with many facets and important milestones.

Chronology

The Psychology Book is organized according to the year associated with an entry. For very early contributions, the date may not be absolutely certain. In most cases, however, we can point to a particular date when a theory was proposed, a book was published, or an event occurred. When there is a matter of debate, the date or period most commonly agreed on will be used.

Acknowledgments

I would like to thank the many scholars whose insightful work informed me as I wrote The Psychology Book. Numerous historians of science, medicine, professional practice, and technology have shaped my thinking about the history of psychology. Members of Cheiron: The International Society for the History of Behavioral and Social Sciences as well as the Forum for History of Human Science and the Society for the History of Psychology all shed much-needed light on the many tributaries of thought and practice that have flowed together to create contemporary psychology. A very special thanks to Alexandra Rutherford, whose support and insight helped make it possible for me to complete this book.