THE PLAN OF THIS BOOK

This book begins with a brief introduction and an overview of personality psychology that you have almost finished reading. The next two chapters concern how personality psychologists do their research, and will be useful for understanding the chapters that follow. Chapter 2 describes the different kinds of data, or information, that psychologists use to better understand personality, and discusses some of the advantages and disadvantages of each kind. The chapter’s goal is to indelibly engrave the following idea into your psyche: There are no perfect indicators of personality; there are only clues, and clues are always ambiguous.⁷ The chapter also addresses the quality of data (reliability, validity, and generalizability) and basic aspects of research design. Chapter 3 describes the basic methods of personality assessment, including how personality tests are constructed, and explains how to evaluate the strength, or effect size, of research findings. It also considers some of the ethical issues evoked by personality assessment, personality research, and scientific research in general.

The second section of this book comprises four chapters that directly address how people differ from one another, the central concern of the trait assessment approach. Chapter 4 discusses the basic question of whether differences between people significantly influence behavior and important life outcomes. (Spoiler Alert: The answer is yes.) Chapter 5 describes research on personality judgment—how we all assess personality in our daily lives, and the circumstances under which it is more and less likely to be accurate. Chapter 6 describes how the psychologists have developed personality trait concepts and tried to identify which traits are the most fundamental, and considers the idea of personality types. In the final chapter in this section, Chapter 7 outlines how and why personality traits develop and also stay the same over the life span, and considers the question of whether personality can be changed, on purpose.

An exciting direction in psychological research is emerging from rapid advances in biology. These discoveries are increasingly applied to the study of personality traits and human nature, and some of that research is surveyed in the third section, which comprises Chapters 8 and 9. Chapter 8 reviews current knowledge about how the architecture and physiology of the nervous system affect behavior and personality. Chapter 9 considers the biological foundations of personality by looking at behavioral genetics, which studies how parents might pass on personality traits to their offspring, and evolutionary psychology, which addresses the inheritance of personality in a deeper sense, by seeking the origins of human nature in the evolutionary history of the species.

In the fourth section, two chapters consider the psychoanalytic approach, which is closely identified with Freud. Chapter 10 is a basic introduction to psychoanalysis that describes the structure of the mind and psychological development, and offers a critique and evaluation of this perspective. Chapter 11 brings the story of psychoanalysis into the present day, with some consideration of the neo-Freudians (psychoanalysts who came after Freud), object relations theory, attachment theory, and modern research relevant to psychoanalytic ideas.

The fifth section includes two chapters that consider the topics of experience and existence. Chapter 12 describes how the phenomenological aspects of existential philosophy that emphasize individual experience developed into an approach called humanistic psychology, which in its modern form considers topics of “positive psychology,” including virtue, mindfulness, and happiness. The theme is that an individual’s particular worldview or way of experiencing reality is central to his or her personality. Chapter 13 takes this phenomenological point one step further, by considering how individuals’ personalities and worldviews—and maybe the whole notion of personality itself—may vary across cultures.

In the sixth section, two chapters describe behaviorism and later approaches to personality that emphasize the processes of learning, motivation, emotion, and cognition that underlie what personality does, as opposed to what personality is. About 70 years ago, some influential psychologists decided to focus on how people (and animals) behave rather than on what might be going on in the hidden recesses of their minds. The original psychologists who took this approach were the classic behaviorists such as John Watson and B. F. Skinner. Over the later decades of the 20th century, three different derivative theories grew out of behaviorism—theories focused on social interaction and cognitive (mental) processes. Interestingly, all three—the theories of John Dollard and Neal Miller, Julian Rotter, and Albert Bandura—were called “social learning theory.” Later, Walter Mischel added a cognitive and phenomenological flavor to social learning theory to produce yet another version, and Carol Dweck elaborated a theory that aims to connect social learning theory with the psychology of personality traits.

At the same time, these theories became increasingly influenced by the rapidly developing field of cognitive psychology. The sixth section of this book describes how some of the concepts and methods of cognitive psychology have been applied to personality, adding insights from the other basic approaches to consider topics including perception, memory, motivation, and emotion. All of these personality processes, from learning to cognition and emotion, are summarized in Chapter 14. The collection of thoughts, feelings and knowledge called the self is considered in Chapter 15.

As a way of summing up and using what we have learned, the seventh and last section of the book focuses on personality psychology as an applied science, one that can be used for practical aims. Chapter 16 summarizes some of the implications of personality for relationships and business. Chapter 17 addresses the extremes of individual differences that are called the personality disorders. With a new edition of the major handbook in psychiatry, the Diagnostic and Statistical Manual of the American Psychiatric Association (commonly known as the DSM), the approach to personality disorders is in the process of major change. The chapter outlines the differences—and tension—between the old and the new approaches, and the implications for understanding, diagnosis, and treatment. The chapter also considers the implications of personality for physical health, including the startling fact that some personality traits are associated with how long a person can be expected to live. At the end of the journey comes Chapter 18, which offers a brief summary of what I think are the most useful lessons from this book, the ones I hope you will remember long after you finish reading it.