Discussion: What Influences Personality Development?

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Personality Theory: From Everyday Observations to Systematic Theories

Questions to be Addressed in this Chapter

Defining Personality

Why Study Personality?

Three Goals for the Personality Theorist

Answering Questions about Persons Scientifically: Understanding Structures, Processes, Development, and Therapeutic Change

Important Issues in Personality Theory

Evaluating Personality Theories

The Personality Theories: An Introduction

Major Concepts

Review

Chapter Focus

I can be selfish, but I believe it is because I try to be perfect. Perfect in the sense I want to be an “A” student, a good mother, a loving wife, an excellent employee, a nourishing friend. My significant other thinks I try too hard to be “Mother Teresa” at times—not that that is a bad thing. But I can drive myself insane at times. I have led a hard childhood and adulthood life; therefore I believe I am trying to make up for all the bad times. I want to be productive, good—make a difference in my world.

I'm a real jackass. I'm intelligent enough to do well in school and study genetics but have no idea when to shut up. I often am very offensive and use quite abrasive language, although I'm shy most of the time and talk to few people. I'm sarcastic, cruel, and pompous at times. Yet I've been told that I'm kind and sweet; this may be true, but only to those I deem worthy of speaking to with some frequency. I'm very fond of arguing and pretty much argue for fun.

I have always been described by others as cynical and/or as having integrity. I would describe myself as inquisitive, philosophical and justice‐oriented. I craze organization, but my room is the messiest one I have seen thus far … like the room

of a toddler. I am introspective but I don't reach many conclusions about myself. I seem very passive and mellow – but I am just too tired to get fired up.

This person is shy at times. They tend to open up to some people. You never know when they're happy or sad. They never show their real feelings, and when they do it's so hard for them. They did have a trauma experience that closed them up— where they seem to be afraid to let their real self show. They are funny and do have a lot of fun and are fun to be around, but at times it's hard to know if they're really having a good time. The person is loved by a lot of people and is an extremely giving person but doesn't like “seriousness.”

These sketches were written by people just like you: students beginning a course on the psychology of personality. When I teach the class, on Day 1, I ask people to describe their personality and that of a friend. Two things happen. First, students can answer the question; when asked to “describe your personality,” they rarely say “I don't know how to do that; it's only the first day of personality class.” Second, as you see here, their answers are often detailed, nuanced, and insightful—so much so that one is tempted to ask: Is the class filled with personality theorists?

In a sense, it is. We're all personality theorists. We ask about ourselves and others: “Why am I so shy?” “Why are my parents so weird?” “Am I so shy because my parents are so weird?” Even before taking a personality class, we devise answers that are sophisticated and often accurate. You already hold ideas about personality and put them to work to understand the events of your day, to anticipate the events of your next day, and to help yourself and your friends handle the stresses, bumps, and bruises of life.

“But”—you may be asking yourself—“if I already know so much about personality, what will I learn in this class? In other words, “What is the professional personality psychologist doing that I'm not doing already?” This chapter addresses this question by introducing the scientific goals and methods of psychologists who study personality. But first, we will define our key term and comment on the status of this scientific field.

Defining Personality

Personality psychology is concerned with the dynamics of intra‐individual functioning and the coherence and thematic unity of particular lives.

Block (1992, p. xiii)

You already have an intuitive understanding of “personality.” Is a formal definition even necessary? It is because—as so often happens with words—different people use the word “personality” in different ways. The differences can create confusion in both an introductory course and the professional field (Cervone, 2005). Let us therefore examine some ways in which the word “personality” is used. We then will provide a formal definition of the term.

In one common usage, people say, for example, that “Ellen DeGeneres has a lot of personality” or “My psych professor has no personality.” Personality here means “charisma”. This is not the way that personality psychologists use the word; this book is most definitely not about “Charisma: Theory and Research”.

Professional psychologists use the word “personality” in two ways. Specifically, they propose two types of personality variables, that is, two types of concepts for understanding people and how they differ.

1. Dispositions.

One type of variable is personality dispositions. In general, in the sciences, dispositions are descriptions; dispositional terms describe what a person or thing tends to do. A glass vase tends to break if you bump into it. “Fragile” is a dispositional term that describes this tendency. Some types of turtles tend to live very long lives. “Longevity” describes this tendency (turtles are “high in longevity” compared to many other species). In the study of personality, psychologists try to identify the personality dispositions that best describe individuals and the major ways that people differ from one another.

People have a lot of tendencies: sleeping when tired, eating when hungry, bored when reading a textbook. Which count as personality dispositions? You can figure this out for yourself. Think about how you use the word “personality,” and you will quickly realize that you employ the word to describe psychological characteristics with two qualities: “personality” tendencies are (a) enduring and (b) distinctive.

• By “enduring,” we mean that personality characteristics are at least somewhat consistent across time and place. If one day you find yourself acting a little strange—maybe because you are stressed about something—

you likely would not say that your “personality has changed” on that day. You use the word “personality” to describe characteristics that endure for long periods of time: months and years and perhaps your entire life.

• By “distinctive,” we mean that personality characteristics differentiate people from one another. If asked to describe your personality, you would not say, “I tend to feel sad when bad things happen but happy when good things happen.” Everybody feels sad/happy when bad/good things happen. These tendencies are not distinctive. But if, like one of our opening sketches, someone is “shy most of the time … sarcastic, cruel, and pompous at times … yet kind and sweet to those deemed worthy of speaking to,” then that is a distinctive—and is therefore a (rather complex) personality disposition.

2. Inner Mental Life.

A second set of concepts refers to inner mental life. Personality psychologists study the beliefs, emotions, and motivations that comprise the mental life of the individual. Conflicts between alternative desires; memories that spring to mind and fill you with emotion; emotions that interfere with your ability to think; long‐term goals that make otherwise mundane tasks meaningful; self‐doubts that undermine efforts to achieve these goals—these and more are the features of mental life targeted by the personality psychologist.

A technical term—used in the quote above, from the personality psychologist Jack Block—for this scientific target is “intraindividual functioning”. Personality psychology is not only concerned with differences between people or interindividual differences. Personality psychologists are fundamentally concerned with the interplay of thoughts and emotions within the mind or intraindividual mental functioning.

Many branches of psychology study mental life. What's unique about personality psychology? One distinctive feature is the field's concern with how multiple aspects of mental life are connected to one another or “cohere” (Block, 1992; Cervone & Shoda, 1999). Compare this interest to the primary interests in other branches of psychology. A cognitive psychologist may study memory. A social psychologist may study self‐concept. An educational psychologist might address perfectionistic tendencies at school. But the personality psychologist is concerned with how these distinct systems cohere in the life of an individual. You just saw such personality coherence in the opening quote above; the person's memory (of a hard life) was connected to her self‐concept (being a productive person who makes

a difference to the world), which, in turn, explained her perfectionism (“striving to be perfect”).

A useful concept to describe these connections is “system”. A system is any connected set of interacting parts that comprise whole. Personality can be thought of as a system. Distinct psychological qualities—beliefs, values, emotions, goals, skills, memories—influence one another and comprise the person as a whole (Mischel & Shoda, 1995; Nowak, Vallacher, & Zochowski, 2005)

We now are in a position to define personality. In psychology, personality refers to psychological systems that contribute to an individual's enduring and distinctive patterns of experience and behavior. As you can see, the definition combines the two meanings above. Ideally, the personality psychologist will be able to identify psychological systems (aspects of inner mental life) that help to explain people's distinctive experiences and actions (their dispositions).

Why Study Personality?

Why take a course in personality? One way to answer this question is to compare the material in this course with other courses in psychology. Consider intro psych—the typical Psych 101. Students are sometimes disappointed with its content. The course does not seem to be about whole, intact people. Instead, one learns about parts of people (e.g., the visual system, the autonomic nervous system, long‐term memory, etc.) and some of the things people do (learning, problem‐ solving, decision‐making, etc.). “Where in psychology,” one reasonably might ask, “does one learn about the whole, intact person?” The answer is here, in personality psychology. Personality theorists address the total person, trying to understand how different aspects of an individual's psychological life are related to each other and relate also to the society and culture in which the person lives (Magnusson, 2012). One reason for studying personality psychology, then, is that it addresses psychology's most complex and interesting topic: the whole, integrated, coherent, unique individual.

Another reason is the impact of personality psychology on the wider intellectual world. Personality theories have been influential not only within scientific psychology. They also have influenced society at large. In fact, they have been so influential that they probably have affected your thinking even before you enrolled in this course. Have you ever said that someone has a big “ego”? Or called a friend an “introvert”? Or asked whether a slip‐of‐the‐tongue reveals something about the

hidden beliefs of the speaker? If so, you were already using terms and ideas that come from personality psychology.

Here are three indications of the influence of personality psychology:

• At the end of the 20th century, scholars (Haggbloom et al., 2002) identified the most influential scientific psychologists of the 20th century. Who made the list? In the top 25, the majority were investigators who contributed to the psychology of personality.

• The end of the century was also the end of the millennium. A television network polled historians and others to determine the 100 most influential people—of any sort—of the past 1000 years. The only psychologist to make the list—and easily, at #12—was a personality theorist: the psychodynamic theorist, Sigmund Freud (A & E's Biography: 100 Most Influential People of the Millennium https://wmich.edu/mus‐gened/mus150/biography100.html).

• In 2007, a statistical analysis identified the highest‐impact book authors in the humanities or social sciences (fields including not only psychology, but also political science, philosophy, linguistics, literary criticism, sociology, and cultural studies). The singularly most‐cited living author was a personality theorist: the social cognitive theorist Albert Bandura (https://www.timeshighereducation.com/news/most‐cited‐authors‐of‐books‐ in‐the‐humanities‐2007/405956.article).

Here, in personality theory and research, you will find the most influential ideas in the history of the psychological sciences.

Three Goals for the Personality Theorist

Now let's return to an earlier question: What is the professional personality psychologist doing that you, the reader, are not?

Consider what you do. You interact—in person and electronically—with friends and family. You observe people not only in person, but also in movies and videos, and (through writing) in books, magazines, and blogs. You think about yourself: your strengths and weaknesses, hopes and plans, and responsibilities to others. And you learn how others do these same things, when they tell you about themselves, their friends and families, and their hopes and dreams. Somehow, from this everyday observations, you develop thoughts about human nature and the main ways that people differ from one another.

For most people, that is plenty of thinking about personality. But personality psychologists are not “most people.” Psychologists who study personality pursue three goals that distinguish their activities from the nonprofessional who is interested in persons.

1. Scientific Observation

Personality psychologists do not observe people casually. Instead, they pursue scientific observation. The features that make observations “scientific” vary from one science to another. In personality psychology, three stand out:

1. Study diverse groups of people. Psychologists cannot base personality theories merely on observations of people they happen to run into in daily life. They must observe diverse groups of individuals, to ensure that conclusions about personality represent the lives the world's citizens. This need is particularly critical because people from different nations and cultures may differ in ways that become apparent only once they are studied within their specific life contexts (Cheng, Wang, & Golden, 2011). Not only nations and cultures, but also subcultures—associated with ethnicity, spiritual beliefs, or economic circumstances—may display distinctive psychological characteristics (Oyserman, 2017).

In today's personality science, researchers often succeed admirably in reaching such diverse participants group. For example, one research team summarized self‐ descriptions of personality from participants in 56 nations (Schmitt et al., 2007). Another studied personality tendencies across regions of the globe and found that more mild climates foster more outgoing (sociable, open‐minded) personality styles. The ability to study global populations is made easier by a technological advance. By analyzing “big data”—large bodies of information acquired by recording computer users' preferences and statements on social media and other internet sites (Bleidorn, Hopwood, & Wright, 2017)—researchers can get information about people throughout the world.

These trends, however, are recent. Before the 21st century, the majority of participants in psychological research were from Europe and North America— which contain less than 20% of the world's population, combined. This is significant in that all of the major theories of personality developed prior to the present century.

2. Ensure that observations of people are objective. A second requirement is “objectivity”. Information that is not influenced by the subjective personal opinions and desires of the person getting the information is called “objective”. If you step on a scale and it tells you your weight, the scale is “objective”: It is not influenced by your own subjective desires for a different weight. Psychologists strive for scientific methods that provide information about personality that is objective.

Objective methods promote a key goal of science: replicability. Whenever one scientist reports a finding, others should be able to replicate it; in other words, they should be able to repeat the procedures and get the same result. Using an example above, if one team of researchers found that mild climates predict outgoing personality styles, you should be able to repeat their procedures and find the same thing.

It turns out that replicability is difficult to achieve—so much so that psychology recently has experienced a “replication crisis” (Shrout & Rodgers, 2017). Researchers have sometimes found it hard to replicate well‐known findings. Although these difficulties primarily have occurred in branches of the field other than personality psychology, the overall question of replicability is significant in our field—particularly so because one valuable source of evidence in personality psychology cannot, even in principle, be replicated: case studies. Case studies are in‐depth examinations of a particular individual (see Chapter 2). For example, a therapist might report a case study of a client in therapy. As a general rule, case studies cannot be replicated; if you read a clinical case study, you cannot contact the client and repeat the study.

3. Use specialized tools to study thinking, emotion, and neurobiological systems. Psychologists observe people, just as you do. But they also make observations using specialized tools. These tools often are designed to overcome specific obstacles to obtaining scientific information. Here are two examples. Suppose that you want to learn about the personality characteristics of large numbers of people. An obstacle is the sheer cost and difficulty of contacting people and having them complete personality tests. A specialized tool researchers use to overcome this obstacle is computer software that assesses personality characteristics by analyzing the language use in social media (Park et al., 2014). A second example is that, if you try to study people's feelings—their moods and emotions—by asking them how

they feel, some people are reluctant to discuss their feelings openly. Researchers have developed tools to assess moods and emotions without ever explicitly asking people to talk about themselves (Quirin, Kazén, & Kuhl, 2009). For example, if research participants are asked to describe the emotion expressed in an abstract image, their descriptions reveal their own emotional state (Bartoszek & Cervone, 2017).

2. Scientific Theory

The fundamental goal of science is to explain events (Salmon, 1989). Scientists develop explanatory frameworks—that is, theories—to explain their scientific observations.

What exactly is a scientific theory? The word “theory” can be used in different ways. For example, you might say that you “have a theory that my friend Liliana is anxious because she's really attracted to some guy and hasn't told him.” Even if you are right, your idea about Liliana is not, in and of itself, a scientific theory of Liliana's personality. Scientific theories of personality have three distinctive qualities; they are systematic, testable, and comprehensive.

1. Systematic. As we have noted, you already have developed lots of different ideas about different people. But you probably have not gone to the trouble of relating all of them to one another. Suppose that on one you say “Liliana is anxious because she's really attracted to some guy and hasn't told him” and on another you say “My mother gets anxious all the time; she must have inherited it.” If so, you usually do not have to relate the statements to each other; people don't force you to explain why one case had an interpersonal cause (relationship breakup) and another had a biological cause (inherited tendencies). But personality psychologists must relate all their ideas to one another, to create a systematically organized theory.

2. Testable. If you tell a friend “My parents are weird,” your friend is not likely to say “Prove it!” But the scientific community says “Prove it!” any time a scientist says anything. The personality psychologist must develop theoretical ideas that can be tested by objective scientific evidence. This is true of any science, of course. But in personality psychology, attaining the goal of a testable theory can be particularly difficult. This is because the field's subject matter includes features of mental life—goals, dreams, wishes, impulses, conflicts, emotions, unconscious mental defenses—that are enormously complex and inherently difficult to study scientifically.

3. Comprehensive. Suppose that you have just rented an apartment and are considering inviting in a roommate to share rent costs. When deciding who to invite, you might ask yourself questions about their personalities: Are they fun loving? Conscientious? Open‐minded? And so forth. Yet there also are a lot of other questions that you do not have to ask: If they are fun loving, is it primarily because they inherited this quality or learned it? If they are conscientious now, are they likely to be more or less conscientious 20 years from now? When thinking about persons, you can be selective, asking some questions and ignoring others. But a personality theory must be comprehensive, addressing all significant questions about personality functioning, development, and individual differences. This is what distinguishes personality theory from theorizing in most other branches of psychology. The personality theorist cannot be satisfied with studying “parts” of persons. The personality theorist is charged with comprehensively understanding the person as a whole.

3. Applications: From Observation and Theory to Practice

As the quotes from students that open this chapter make clear, people formulate insightful ideas about personality prior to studying personality psychology. Yet, in everyday life, people rarely convert their personal insights into systematic applications. You may recognize that one friend's problem is a lack of self‐ confidence and that another's is an inability to open up emotionally. Yet, after realizing this, you probably don't design therapies to boost people's confidence in themselves or enable them to open up. Personality psychologists, however, do this. They aim not only to develop testable, systematic theory but also to convert their theoretical ideas into beneficial applications.

In fact, many of the personality theorists you will learn about in this book did not start out in personality psychology. Instead, they often first worked as counselors, clinical psychologists, or physicians. Their personality theories were efforts to understand why their clients were experiencing psychological distress and how that distress could be reduced.

In summary, personality psychologists aim to (1) to observe people scientifically, (2) develop theories that are systematic, testable, and comprehensive, and (3) to

turn their research findings and theoretical conceptions into practical applications. It is these goals that distinguish the work of the personality psychologist from that of the poet, the playwright, the pop psychologist—or the student writing personality sketches on the first day of class. Lots of people develop insightful ideas about the human condition. But the personality psychologist is uniquely charged with organizing theoretical ideas into comprehensive, testable, and practical theories.

Throughout this book, we evaluate the personality theories by judging how well they achieve these goals. This book's final chapter, a commentary on the current state of the field that can be found on the text's companion website www.wiley.com/college/cervone, judges how successful the field of personality psychology as a whole has been in achieving these five aims.

Answering Questions about Persons Scientifically: Understanding Structures, Processes, Development, and Therapeutic Change

Personality psychologist addresses four distinct topics; in other words, there are four issues that every personality theory must address. We can introduce them with a simple “mental experiment”.

Think of someone you know well, for example, a good friend or family member. Two things you know for sure are:

1. Whatever the individual's personality is like today, it likely was similar last month and last year, and likely will be similar next month and next year. You might say that personality is “stable” over time.

2. Despite this stability in personality, the individual's thoughts, feelings, and actions also change. Sometimes they are happy and other times sad. Sometimes they are in control of their emotions and sometimes they “fly off the handle.”

Two things you do not know absolutely for sure, but that probably think are correct, are:

3. If you saw the person when they were a toddler or a grade schooler, their personality would not be the same as it is now. Their personality likely has changed, or “developed,” over time.

4. If the person suddenly experiences a period of psychological distress—for example, a period of depression or anxiety—they probably could “bounce back” from this. In fact, there might be something you could do to improve the person's psychological well‐being.

These four points correspond directly to the topics addressed by personality psychologists. The psychologist introduces formal scientific terms to describe the topics, but the topics themselves are fundamentally the same. They are: (1) personality structure—the enduring “building blocks” of personality; (2) personality process—dynamic changes in thinking, emotion, and motivation that can occur from one moment to the next; (3) growth and development—how we develop into the unique person each of us is, and (4) psychopathology and behavior change—how people change and why they sometimes resist change or are unable to change. We introduce these topics now. You will see them again, over and over, in later chapters.

Structure

People possess psychological qualities that endure from day to day and from year to year. The enduring qualities that distinguish individuals from one another are referred to as personality structures.

Structural concepts in personality psychology are similar to structural concepts you are familiar with from other fields. For example, from study of human biology, you already know that there are enduring biological structures including individual organs (the heart, the lungs) and organ systems (the circulatory system, the digestive system). Analogously, personality theorists hope to identify enduring psychological structures. These structures may involve emotion (e.g., a biological structure that contributes to good or bad mood), motivation (e.g., a desire to achieve succeed or to be accepted by others), cognition (e.g., a negative belief about oneself that contributes to states of depression, Beck, 1991), or skills (e.g., a high or low level of “social intelligence,” Cantor & Kihlstrom, 1987).

You will see throughout this textbook that the different personality theories provide different conceptions of personality structure. A more technical way of saying this is that the theories adopt different units of analysis when analyzing

personality structure (Little, Lecci, & Watkinson, 1992). The “units of analysis” idea is important, so we will illustrate it.

As you read this textbook, you may be sitting in a chair. If we ask you to describe it, the chair, you may say that it “weighs about 15 pounds,” or that it “is made of wood,” or that it “is unattractive”. Weight, physical substance (the wood), and attractiveness are different units of analysis for describing the chair. Although the units may be related in some way (e.g., wood chairs may be heavier than plastic ones), they plainly are distinct.

The general idea is that virtually anything can be described in more than one way—that is, through more than one unit of analysis. Personality is no exception. The different theories of personality you will learn about in this book use different units of analysis to analyze personality structure. The resulting analyses may each be correct, in their own way. Yet each may provide different types of information about personality.

We will illustrate this point with an example: a difference between “trait” and “type” units of analysis.

One popular unit of analysis is that of a personality trait. The word trait generally refers to a consistent style of emotion or behavior that a person displays across a variety of situations. Someone who consistently acts in a way that we call “conscientious” might be said to have the trait of “conscientiousness”. A term that is essentially synonymous with trait is disposition; traits describe what a person tends to do or is predisposed to do. You probably already use trait terms to describe people. If you say that a friend is “outgoing,” “honest,” or “disagreeable,” you are using trait terms. There is something implicit—something that “goes without saying”—when you use these terms. If you say that a friend is, for example, “outgoing,” the term implies two things: (1) the person tends to be outgoing on average in his/her own daily behavior (even if, on occasion, he/she does not act this way), and (2) the person tends to be outgoing compared to others. If you use trait terms this way, then you are using them in the same way as most personality psychologists do.

Traits usually are thought of as continuous dimensions. Like the biological traits of height and weight, people have more or less of a given trait, with most people being in the middle of the dimension.

A different unit of analysis is type. A personality “type” is a clustering of many different traits. For example, some researchers have explored combinations of personality traits and suggested that there are three types of persons: (1) people who respond in an adaptive, resilient manner to psychological stress; (2) people who respond in a manner that is socially inhibited or emotionally overcontrolled; and (3) people who respond in an uninhibited or undercontrolled manner (Asendorpf, Caspi, & Hofstee, 2002).

Types, unlike traits, may be thought of as distinct categories. In other words, people of one versus another type do not simply have more or less of a given characteristic but have categorically different characteristics.

Process

Just as theories can be compared in terms of how they treat personality structure, one can compare their treatment of personality processes. In any scientific field, a “process” is something that changes over time; as the philosopher Wittgenstein put it, we use the word “process” to refer to psychological phenomena that “have duration and a course” (Wittgenstein, 1980, §836). A personality process thus is a psychological activity (involving thoughts, feelings, or actions) that may change over relatively brief periods of time.

Even though you are the same person from one day to the next, you experience rapidly changing personality processes all the time. One moment you are studying. The next, you are distracted by thoughts of a friend. Next, you're hungry and getting a snack. Then you're feeling guilty about not studying. Next, you're feeling guilty about overeating. This rapidly changing flow of motivation, emotion, and action is what personality psychologists attempt to explain when studying personality processes.

Personality processes are often referred to by a more technical name: personality “dynamics”. When using this term, psychologists are borrowing a word from a different field of study: physics. In physics, “dynamics” refers to the ways in which physical objects move across some period of time (e.g., how an object moves toward Earth if you drop it). In personality, “dynamics” refer to psychological processes (involving thinking, emotion, or motivation) that change over time (Cervone & Little, 2017).

Study of personality processes, or dynamics, is where the contemporary science of personality started. European psychologists of the late 19th century became

interested in how different parts of mental life—for example, memory of past events and conscious experiences in the present—become connected to one another in the self‐concept of an individual person (Lombardo & Foschi, 2003). Throughout the first two‐thirds of the 20th century, dynamic processes remained a centerpiece of personality theory. In the late 20th century, personality psychology's focus of attention shifted somewhat, with more researchers studying the stable differences between people rather than the personality dynamics of the individual. But in the current field, the study of personality dynamics is, in a sense, “making a comeback” (Rauthmann, in press). Researchers increasingly explore dynamic changes in personality dynamics that occur across the diverse circumstances of an individual's life.

Just as in the study of personality structure, one finds that, in the study of personality processes, different theorists employ different units of analysis. The differences commonly involve different approaches to the study of motivation. Personality theorists emphasize different motivational processes. Some highlight basic biological drives. Other theorists argue that people's anticipations of future events are more important to human motivation than are biological drive states experienced in the present. Some theorists emphasize the role of conscious thinking processes in motivation. Others believe that most important motivational processes are unconscious. To some, the motivation to enhance and improve oneself is most central to human motivation. To others, such an emphasis on “self‐ processes” underestimates the degree to which, in some cultures of the world, self‐ enhancement is less important to motivation than is a desire to enhance one's family, community, and wider world. In their explorations of motivational processes, the personality theorists you will read about in this book are attempting to bring contemporary scientific evidence to bear on classic questions about human nature that have been discussed and debated in the world's intellectual traditions for more than two millennia.

Growth and Development

Personality theorists try to understand not only what individuals are like in the here and now, but how they got this way. They strive, in other words, to understand personality development (Mroczek & Little, 2006; Specht, 2017).

The overall study of personality development encompasses two challenges that are relatively distinct. One is to characterize patterns of development that are experienced by most, if not all, persons. A theorist might, for example, posit that

all individuals develop through a distinct series of stages, or that certain motives or emotional experiences are more common at one versus another age for most persons. A second challenge is to understand developmental factors that contribute to individual differences. What factors cause individuals to develop one versus another personality style?

In the study of individual differences, a classic division of possible causes separates “nature” from “nurture”. We may be who we are because of our biological nature, that is, because of biological features that we inherited. Alternatively, our personality may reflect our nurturing, that is, our experiences in our family and in society. In a joking manner, we might say, “If you don't like your personality, who should you blame: Your parents, because of the way they nurtured you? Or your parents, because of the genes they passed on to you that shaped your biological nature?”

At different points in its history, psychological research has tended to highlight either nature or nurture as causal factor. In the middle parts of the 20th century, theorists focused heavily on environmental causes of behavior and devoted relatively little attention to genetic influences. Starting in the 1970s, investigators began systematic studies of similarity in the personalities of twins. These studies provided unambiguous evidence that inherited factors contribute to personality.

In recent years, there has been a third trend. Researchers have identified interactions between genetic and environmental factors. A critical finding is that environmental experiences activate genetic mechanisms, essentially “switching” genes on and off (Champagne, 2018). Since genes code for proteins that become the structural material of the body, this means that certain types of experiences can alter the biology of the organism (Gottlieb, 1998; Rutter, 2012). This finding, in turn, implies that the traditional notion of nature versus nurture hardly makes sense. Nature and nurture—experience and biology—are not competing forces; instead, they work together, shaping the organism across its life span (Lewontin, 2000; Meaney, 2010).

You might already be asking yourself: What aspects of personality are affected by what types of biological and environmental influences? This is a big question whose answers are considered throughout this textbook. For now, though, we will provide a quick preview of some of the factors highlighted by contemporary findings in personality psychology.

Genetic Determinants

Genetic factors contribute strongly to personality and individual differences (Kim, 2009). Contemporary advances enable the personality psychologist to pinpoint specific paths through which genes affect personality. One main path is through temperament, a term that refers to biologically based emotional and behavioral tendencies that are evident in early childhood (Strelau, 1998).

Temperament characteristics that have been studied in depth are fear reactions and inhibited behavior (Fox, Henderson, Marshall, Nichols, & Ghera, 2005). People differ considerably in the degree to which they respond fearfully, especially when encountering unfamiliar, novel situations (e.g., a social setting with many strangers). Genes contribute to individual differences in brain systems that are involved in this fear response. These biological differences, in turn, produce psychological differences in behavior and emotion (Fox & Reeb‐Sutherland, 2010). Since genetic factors contribute to the development of the brain, in this work, the psychologist can identify a precise link from genes to biological systems to temperament, as expressed in emotion and behavior. An interesting feature of this work is that it points to the impact not only of genes, but also of the environment. Some evidence indicates that temperamentally shy children change, becoming less shy, when they experience day care in which they encounter large numbers of other children every day (Schmidt & Fox, 2002), though data on this point are somewhat mixed (Kagan, 2011).

Genetic bases of personality also are explored by evolutionary psychologists, that is, psychologists who study the evolutionary basis of psychological characteristics (Buss & Hawley, 2011). Evolutionary psychologists propose that contemporary humans possess psychological tendencies that are a product of our evolutionary past. People are predisposed to engage in certain types of behavior because those behaviors contributed to survival and reproductive success over the course of human evolution. An evolutionary analysis of genetic influences differs fundamentally from the analyses reviewed in the two preceding paragraphs. In an evolutionary analysis, investigators are not interested in genetic bases of individual differences. Instead, they are searching for the genetic basis of human universals, that is, psychological features that all people have in common. Most of our genes are shared. Even so‐called racial differences involve merely superficial differences in features such as skin tone; the basic structure of the human brain is universal (Cavalli‐Sforza & Cavalli‐Sforza, 1995). The evolutionary psychologist suggests, then, that we all inherit psychological mechanisms that predispose us to respond to the environment in ways that proved successful over the course of evolution. For

example, some scientists who study emotion suggest that a number of basic emotions (e.g., anger, sadness, joy, disgust, fear) are products of evolution (Ekman, 1993, 1994; Izard, 1994; Panksepp, 2011).

Culture

Significant among the environmental determinants of personality are experiences individuals have as a result of membership in a particular culture: “Culture is a key determinant of what it means to be a person” (Benet‐Martinez & Oishi, 2008, p. 543). Each culture has its own institutionalized and sanctioned patterns of learned behaviors, rituals, and beliefs. These cultural practices, which in turn often reflect long‐standing religious and philosophical beliefs, provide people with answers to significant questions about the nature of the self, one's role in one's community, and the values and principles that are most important in life. As a result, members of a culture may share personality characteristics.

Interestingly, people often may be unaware of shared cultural tendencies because they take them for granted. For example, if you live in North America or western Europe, you may underestimate the extent to which your conception of yourself and your goals in life are shaped by a culture that strongly values individual rights, in which individuals compete in an economic marketplace, and in which the society as a whole is marked by high levels of financial inequality (Stephens, Markus, & Phillips, 2014). Since everyone in these regions of the world experiences these cultural features, we take them for granted and may assume that they are universal. Yet much evidence indicates that people in other regions of the world experience different cultural features. Asian cultures appear to place a greater value on a person's contribution to his or her community rather than on individualism and personal gain (Nisbett, Peng, Choi, & Norenzayan, 2001). In fact, even within the Western world, cultural beliefs about the individual's role in society have changed from one historical period to another. The idea that individuals compete against one another in an economic marketplace in order to improve their position in life is a feature of contemporary Western societies, but it was not evident in these same societies in the Middle Ages (Heilbroner, 1986).

Culture, then, may exert an influence on personality that is subtle yet pervasive. The culture we live in defines our needs and our means of satisfying them, our experiences of different emotions and how we express what we are feeling, our relationships with others and with ourselves, what we think is funny or sad, how

we cope with life and death, and what we view as healthy or sick (Markus & Kitayama, 2011).

Social Class

Although certain patterns of behavior develop as a result of membership in a culture, others may develop as a result of membership in a particular social class within a given culture. Many aspects of an individual's personality can only be understood by reference to the group to which that person belongs. One's social group—whether lower class or upper class, working class or professional—is of particular importance. Research indicates that socioeconomic status influences the cognitive and emotional development of the individual (Bradley & Corwyn, 2002). Social class factors affect not only educational opportunities, job prospects, and access to social resources. They may also indirectly affect social experiences, such as the experience of small or large networks of friends and family, and psychological qualities such as the tendency to focus, or not, on one's long‐term future (Markus & Stevens, 2017).

Family

Another environmental factor of profound importance is the influence of the family (Park, 2004; Pomerantz & Thompson, 2008). Parents may be warm and loving or hostile and rejecting, overprotective and possessive, or aware of their children's need for freedom and autonomy. Each pattern of parental behavior affects the personality development of the child. Parents influence their children's behavior in at least three important ways:

1. Through their own behavior, parents present situations that elicit certain behavior in children (e.g., frustration leads to aggression).

2. Parents serve as role models for identification. 3. Parents selectively reward behaviors.

Experiences in a family can create both similarities and differences among family members.

At first, we may think of family practices as an influence that makes family members similar to one another. Yet family practices also can create within‐family differences. Consider differences between male and female family members. Historically, in many societies, male children have received family privileges and

opportunities that were unavailable to female children. These differences in how families have treated boys and girls surely did not make boys and girls similar to one another; rather, they contributed to differences in male and female development. In addition to gender, other family practices that may produce differences between family members involve birth order. Parents sometimes express subtle preferences toward firstborn children (Keller & Zach, 2002), who tend to be more achievement‐oriented and conscientious than later‐born siblings (Paulhus, Trapnell, & Chen, 1999).

Peers

What environmental features outside of family life are important to personality development? The child's experiences with members of his or her peer group are one feature. Personality development is influenced by peer groups as a whole— who socialize the individual into rules and norms for behavior—and by one‐on‐one relationships within peer groups, which can shape people's perceptions of themselves (Reitz, Zimmermann, Hutteman, Specht, & Neyer, 2014). Some psychologists view peer influences as more important to personality development than family experiences (Harris, 1995). Perhaps “the answer to the question ‘Why are children from the same family so different from one another?’ (Plomin & Daniels, 1987) is, because they have different experiences outside the home and because their experiences inside the home do not make them more alike” (Harris, 1995, p. 481). Peer groups. These experiences may affect personality in an enduring manner. For example, children who experience low‐quality friendships that involve a lot of arguing and conflict tend to develop disagreeable, antagonistic styles of behavior (Berndt, 2002).

Psychopathology and Behavior Change

Constructing a personality theory may strike you as an ivory tower activity, that is, an abstract intellectual exercise that fails to relate to the important concerns of everyday life. Yet personality theories are potentially of great practical importance. People often face complicated psychological problems: They are depressed and lonely, a close friend is addicted to drugs, they are anxious about sexual relations, frequent arguments threaten the stability of a romantic relationship. To solve such problems, one requires some sort of conceptual framework that specifies causes of the problem and factors that might bring about change. In other words, one needs a personality theory.

Historically, the practical problems that have been most important to the development of personality theories have involved psychopathology. Many of the theorists discussed in this book were also therapists. They began their careers by trying to solve practical problems they faced when trying to help their clients. Their theories were, in part, an attempt to systematize the lessons about human nature that they learned by working on practical problems in therapy.

Although not all personality theories had clinical origins, for any theory, a crucial bottom line for evaluating the theoretical approach is to ask whether its ideas are of practical benefit to individuals and to society at large.

Important Issues in Personality Theory

We have just reviewed four topic areas in the study of personality: (1) personality structure, (2) personality processes, (3) personality development, and (4) psychopathology and behavior change. Next, we will consider a series of conceptual issues that are central to the field. By “conceptual issues,” we mean a set of questions about personality that are so fundamental that they may arise no matter what topic one is addressing and that one must address regardless of one's theoretical perspective.

Philosophical View of the Person

No theory can be adequately understood without some knowledge of the cultural and personal soil from which it springs.

Rogers (1959, p. 185)

Personality theorists do not confine themselves to narrow questions about human behavior. Instead, they boldly tackle the big, broad question: What is the basic nature of human nature? Personality theorists, in other words, provide philosophical views about the basic nature of human beings. One critical consideration when evaluating a theory, then, is the overall view of the person that it provides.

Personality theories embrace strikingly different views of the essential qualities of human nature. Some view people as rational actors—beings who reason about the world, weigh the costs and benefits of alternative courses of action, and behave based on these rational calculations. To others, human nature is animalistic, with people primarily driven by irrational forces.

Where did the difference among theories come from? Philosophical views arise in sociohistorical contexts. In other words, the historical circumstances of the psychologist influence the theory that he or she develops. In the late 19th century, scientists explored the physics of energy—and Sigmund Freud proposed an energy‐based model of mind (Chapter 3). The crisis of World War II prompted a broad intellectual movement that confronted issues of personal responsibility and freedom of choice, and this movement, in turn, informed the humanistic and phenomenological personality theories (Chapters 5 and 6) that developed in the 1950s (Fulton, 1999). At around the same time, mathematicians and engineers developed machines that seemed to think – computers—and psychologists adopted the metaphor that the mind is like a computer. In our current era, scientists in multiple fields explore the nature of complex systems (Holland, 2014; a complex system is one that contains large numbers of highly interacting parts)—and personality theorists adopt “systems” perspectives on personality structure and dynamics (Kuhl, Quirin, & Koole, 2015; Mayer, 2015; Mischel &

Internal and External Determinants of Behavior

Is human behavior and experience determined by processes inside the person or causes external to the person? If you are a hardworking student, is it because of your confidence and personal goals (an internal cause) or your parents and schooling (an external cause). If you are disappointed in yourself, is it because of your perfectionistic thinking (an internal cause) or because social forces provided less support and fewer opportunities to people of your nationality, ethnic group, or gender (an external cause)?

All theories of personality recognize that both external and internal factors are influential. Nonetheless, they differ considerably in the emphasis they give to one or the other. Consider the differences between the most influential psychologists of the 20th century: Sigmund Freud and B. F. Skinner. According to Freud, we are controlled by internal forces: unconscious impulses and emotions that are buried deep in our unconscious minds. According to Skinner, we are controlled by external forces: environmental rewards and punishments that govern our actions. “A person does not act upon the world, the world acts upon him,” Skinner writes (1971, p. 211).

Freud's and Skinner's views are extreme in the light of contemporary scientific knowledge. Virtually all personality psychologists today acknowledge both

external and internal determinants of human action. Nonetheless, contemporary theories continue to differ markedly in the degree to which they emphasize one versus the other factor. These differences become apparent when one examines the basic variables—or, as we called them earlier, the basic units of analysis—of a given theory. Consider two perspectives you will read about in later chapters. In trait theories of personality, the basic units of analysis refer to structures in the person that purportedly are inherited and produce highly generalized patterns of behavior (McCrae & Costa, 2008). In social cognitive theories of personality, the basic units of analysis are knowledge structures and thinking processes that are acquired through interaction with the social and cultural environment (Bandura, 1999; Mischel & Shoda, 2008). As you can infer from their basic units, these theories differentially emphasize internal and external determinants of personality.

Consistency Across Situations and Over Time

How consistent is personality from situation to situation? To what extent are you “the same person” when with friends as you are with your parents? Or when you are at a party versus present during a classroom discussion? And how consistent is personality across time? How similar is your personality now to what it was when you were a child? And how similar will it be 20 years from now?

Answering these questions is more difficult than it may appear. In part, this is because one has to decide on what counts as an example of personality consistency versus inconsistency. Consider a simple example. Suppose that you have two supervisors at a job, one male and one female, and that you tend to act in an agreeable manner toward one supervisor and disagreeably toward the other. Are you being inconsistent in your personality? If one thinks that a basic feature of personality is agreeableness, then the answer is yes. But suppose this situation were analyzed by a psychologist who adheres to psychoanalytic theory, which suggests that (1) people you encounter in your adult life may symbolically represent parental figures and (2) a basic personality dynamic involves attraction toward one's opposite‐sex parent and rivalry toward the same‐sex parent— something called an “Oedipal complex”. From this view, you may be acting in a very consistent manner. The different job supervisors may symbolically represent different parental figures, and you may be consistently reenacting Oedipal motives that cause you to act in a different manner toward one versus the other person.

Even if people agree on what counts as consistency, they may disagree about the factors that cause personality to be consistent. Consider consistency over time. It

unquestionably is the case that individual differences are stable, to a significant degree, over long periods of time (Fraley, 2002; Roberts & Del Vecchio, 2000). If you are more extraverted than your friends today, you are quite likely to be more extraverted than these same people 20 years from now. But why? One possibility is that the core structures of personality are inherited and that they change little across the course of life. Another possibility, however, is that the environment plays a critical role in fostering consistency. Exposure to the same family members, friends, educational systems, and social circumstances over long periods of time may contribute to personality consistency over time (Lewis, 2002).

No personality theorist thinks that you will fall asleep an introvert and wake up the next morning an extravert. Yet the field's theoretical frameworks do provide different views on the nature of personality consistency and change and on people's capacity to vary their personality functioning across time and place. To some theorists, variation in behavior is a sign of inconsistency in personality. To others, it may reflect a consistent personal capacity to adapt one's behavior to the different requirements of different social situations (Mischel, 2004).

The Unity of Experience and Action and the Concept of Self

Our psychological experiences generally have an integrated, or coherent, quality to them (Cervone & Shoda, 1999b). Our actions are patterned and organized, rather than random and chaotic. As we move from place to place, we retain a stable sense of ourselves, our past, and our goals for the future. There is a unity to our experiences and action.

Although we take it for granted that our experiences are unified, in some sense this fact is quite surprising. The brain contains a large number of information‐ processing systems, many of which function at the same time, in partial isolation from one another (Pinker, 1997). If we examine the contents of our own conscious experiences, we will find that most of our thoughts are fleeting. It is hard to keep any one idea in mind for long periods. Seemingly random ideas pop into our heads. Nonetheless, we rarely experience the world as chaotic or our lives as disjointed. Why?

A major challenge for personality science is to understand how people developed a consist, unified sense of self.

There are two types of answers to this question. One is that the multiple components of the mind function as a complex system. The parts are

interconnected, and the patterns of interconnection enable the multipart system to function in a smooth, coherent manner. Computer simulations of personality functioning (Nowak, Vallacher, & Zochowski, 2002), as well as neuroscientific investigations of the reciprocal links among brain regions (Sporns, 2010; Tononi & Edelman, 1998), are beginning to shed light on how the mind manages to produce coherence in experience and action.

The second type of answer involves the concept of the self. Although we may experience a potentially bewildering diversity of life events, we do experience them from a consistent perspective, that of ourselves (Harré, 1998). People construct coherent autobiographical memories, which contribute to coherence in our understanding of who we are (Conway & Pleydell‐Pearce, 2000). The concept of the self, then, has proven valuable in accounting for the unity of experience (Baumeister, 1999; Robins, Norem, & Cheek, 1999; Robins, Tracy, & Trzesniewski, 2008).

Varying States of Awareness and the Concept of the Unconscious

Are we aware of the contents of our mental life? Or do most mental activities occur outside of awareness or unconsciously?

On the one hand, much of the brain's activities unquestionably occur outside of awareness. Consider what is happening as you read this book. Your brain is engaging in large numbers of functions ranging from the monitoring of your internal physiological state to the deciphering of the marks of ink that constitute the words on this page. All this occurs without your conscious attention. You do not consciously have to think to yourself “I wonder if these squiggles of ink form words” or “Maybe I should check to see if sufficient amounts of oxygen are getting to my bodily organs.” These functions are executed automatically. But these functions are not the ones of main interest to the personality psychologist.

Personality scientists ask whether significant aspects of personality functioning— motivation, emotions—occur outside of awareness. If there is evidence that they do, the personality scientist tries to conceptualize the mental systems that give rise to conscious and unconscious processes (Kihlstrom, 2008; Pervin, 2003). The fact that some brain functions occur outside of awareness does not imply that the most significant personality processes occur without our awareness. People engage in

much self‐reflection. They are particularly likely to reflect on themselves when they face life circumstances of great importance, where the decisions that are made (e.g., whether and where to attend college, whether to marry a certain person, whether to have children, what profession to pursue) have major long‐term consequences. In these critical circumstances, conscious processes are influential. Thus, many personality psychologists study conscious self‐reflection, even while recognizing that numerous aspects of mental life occur outside of awareness.

The Influence of the Past, Present, and Future on Behavior

Are we prisoners of our past? Or is our personality shaped by present events and personal aspirations for the future? Theorists agree that behavior can be influenced only by factors operating in the present; a basic principle of causality is that presently active processes are the causes of events. In this sense, only the present is important in understanding behavior. But the present can be influenced by experiences in the remote past or in the recent past. Similarly, what one is thinking about in the present can be influenced by thoughts about the immediate future or the distant future. People vary in the extent to which they worry about the past and the future. And personality theorists differ in their concern with the past and the future as determinants of behavior in the present. As you will see in the chapters ahead, some theorists suggest that we are primarily prisoners of our past. Psychoanalytic theory posits that personality structures are formed through experiences in childhood and that the personality dynamics established then persist throughout the life course. Others are harshly critical of this psychoanalytic conclusion. Personality construct theory (Chapter 11) and social‐cognitive theory (Chapters 12–13) suggest that people have the capacity to change their own personal capabilities and tendencies and to explore the social and psychological systems that give people this lifelong capacity for personal agency (Bandura, 2006).

Meaning and Reasons for Action

If you observe some people and want to describe what they are doing, how would you do it? It sounds simple at first: Just count their behaviors. You might count the number of times a person talks, or smiles, or frowns, or checks social media. But is this sufficient? Are any two people who have the same “counts”—for example, 6 talks, 5 smiles, 2 frowns, and 29 social media checks in an hour—the same, in a psychologically significant way?

The problem with “just counting” is that the counts overlook people's reasons for action. One person might be smiling because she's happy. Another might smile as a way of putting other people in a good mood. Yet others might smile to make a good impression or as a strategy to control their anxiety. The existence of different reasons means that people who are doing the same thing behaviorally are not the same psychologically. Reasons for action may vary widely from one person to the next. When one research team asked people why they had sex, participants identified more than a dozen different reasons: stress reduction, attaining social status, expressing love and commitment to someone, sheer physical pleasure, feelings of obligation, and more (Meston & Buss, 2007).

The implication is that, in personality theory and research, one often must pay attention to subjective meaning rather than merely to observable behavior. People do not respond merely to physical stimuli in the environment. They respond to social circumstances that have personal meaning to them.

Although this point is obvious once stated, you will see that personality theories differ in the degree to which they pay attention to subjective meaning and people's reasons for action. Some theorists do count behaviors (Chapter 8) or study the influence of physical stimuli (Chapter 10) without deeply exploring people's reasons for action. However, most of the personality theorists are centrally concerned with the way in which people make sense of—or “assign meaning to”— the situations, events, and relationships that make up their lives.

Can We have a Science of Personality? What kind of a Science can it be?

A final issue of importance concerns the type of theory of personality that one reasonably can pursue. We have taken it for granted thus far that one can craft a science of personality, in other words, that the methods of science can inform the nature of persons. This assumption seems to be a safe one. People are objects in a physical universe. They consist of biological systems comprised of physical and chemical parts. Science thus should be able to tell us something about them.

Nonetheless, one can reasonably question the forms of scientific analysis that can be applied to the understanding of persons. Much of the progress of science has involved analyses that are reductionistic. A system is understood by reducing a complex whole to its simpler parts and showing how the parts give rise to the functioning of the whole.

One challenge is building a theory of personality is cultural variation; the nature of personality and individual differences may vary from one culture to another. For example, in India, people recognize three main personality traits, the trigunas, which are characteristics first identified centuries ago in Hindu philosophy (Singh, Misra, & De Raad, 2013). These traits generally are not found in studies conducted in Western cultures, such as the United States.

Such analyses work wonderfully when applied to physical systems. A biological system, for example, can be understood in terms of the biochemistry of its parts. The chemistry, in turn, can be understood in terms of the underlying physics of the chemical components. But personality is not merely a physical system. As just noted, people respond to meaning. There is no guarantee that the traditional scientific procedures of breaking a system into constituent parts will be sufficient to understand processes of meaning construction. Numerous scholars have suggested that importing the methods of the physical sciences into the study of human meaning systems is a mistake (e.g., Geertz, 2000). To such commentators, the idea that people have “parts” is “at best a metaphor” (Harré, 1998, p. 15). The risk of adopting this metaphor is that, to use a cliche, “the whole may be greater than the sum of the parts.”

By analogy, consider an analysis of a great work of art. In principle, one could analyze its parts: There's paint of one color over here, paint of some other color there, and so on. But this sort of analysis will not enable one to understand the greatness of the painting. This requires viewing the work as a whole and understanding the historical context in which it was made. By analogy, a listing of the psychological parts of an actual person may, in principle, fail to portray the whole individual and the developmental processes that contributed to his or her uniqueness. A question to ask yourself when reading this textbook, then, is whether the personality theorists are as successful as was da Vinci at providing holistic psychological portraits of complex individuals.

Evaluating Personality Theories

As we have noted, a unique feature of the scientific field of personality psychology is that it contains more than one guiding theory. Multiple theories of personality inform us about human nature and individual differences. A natural question, then, is how to evaluate the theories, one versus the other. How can one judge the strengths and limitations of the various theories? What criteria should be used to evaluate them?

To evaluate something, one generally asks what it is supposed to do. One then can judge how well it is doing it. A more formal way to say this is that one asks about the functions that the entity is supposed to serve. One then can evaluate the degree to which it is carrying out those functions. Like all scientific theories, theories of personality can serve three key functions: They can (1) organize existing information, (2) generate new knowledge about important issues, and (3) identify entirely new issues that are deserving of study.

The first of these functions is obvious. Research provides an array of facts about personality, personality development, and individual differences. Rather than merely listing these facts in an unordered manner, it would be useful to organize them systematically. A logical, systematic ordering of facts would enable one to keep track of what scientists know about personality. This can make it easier to put that knowledge to use.

The second function is somewhat less obvious. In any field of study, there are issues—involving both basic science questions and applications of scientific knowledge—that everyone in the field recognizes as important. A good theory fosters new knowledge about these issues. It is generative. The theory helps people to generate new knowledge about the topics they recognize as important to their field. In biology, Darwin's theory of natural selection was useful not only because it organized known facts about the world's flora and fauna. Its additional value is that it opened new pathways of knowledge about biology. In personality psychology, some theories have proven to be highly generative. They have prompted researchers who are familiar with the theory to use its ideas to generate new knowledge about personality.

The third function is of particular interest to both the personality scientist and the public at large. A personality theory may identity entirely new areas of study— areas that people might never have known about were it not for the theory. Psychodynamic theory opened the door to psychological issues that were utterly novel to most people: the possibility that our most important thoughts and emotions are unconscious, the possibility that events early in childhood determine our adult personality characteristics. Other theories also have this quality. Evolutionary psychology (reviewed in Chapter 9) makes the novel suggestion that contemporary patterns of thought and behavior are not learned in contemporary society but, instead, are inherited from our ancestral past. Behaviorism (Chapter 10) raises the possibility that actions that we attribute to our free choice, or free will, are ultimately caused by the environment. These theories' fascinating and sometimes radical hypotheses about human nature have prompted much valuable new investigation into human nature.

In sum, you can evaluate the theories you will learn about in this textbook by gauging their success in (1) organizing information, (2) generating knowledge, and (3) identifying important issues to study.

The Personality Theories: An Introduction

We have now reviewed a series of points: topics that must be addressed by a personality theory, important issues that arise as one confronts these topics, and criteria that can be used to evaluate a theory of personality. Now, in the final section of this chapter, we turn to the theories themselves.

The Challenge of Constructing a Personality Theory

By this point in our chapter, it is clear that constructing a comprehensive theory of personality is extremely difficult. Theorists must pursue a challenging set of scientific goals that go beyond one's intuitive thinking about personality. They must address a broad set of what, how, and why questions about personality structure, processes, development, and change. They must consider determinants of personality ranging from the molecular to the sociocultural and conceptual issues ranging from the philosophical view of persons that is embedded in their theory to

the question of whether one can have a scientific theory of persons in the first place.

Does any one person do this ideally? Is there a single theory that is so comprehensive in its scope, so consistent with scientific evidence, and so uniquely able to foster new knowledge that it is accepted universally? The answer, quite simply, is no. There exist different theoretical frameworks. Each has its strengths, and each its limitations. More important, each has its unique virtues; in other words, each of a variety of theories provides some unique insights into human nature. It is for this reason that this textbook is organized around personality theories—plural.

The Personality Theories: A Preliminary Sketch

What theoretical frameworks have had the biggest impact on the field? This book will introduce you to six theoretical approaches. We provide a brief sketch of these approaches here, so that you can get a sense of the terrain ahead.

We begin with psychodynamic theory (Chapters 3 and 4), the approach pioneered by Freud. Psychodynamic theory views the mind as an energy system; the basic biological energies of the body reside, in part, in the mind. Mental energies, then, are directed to the service of basic bodily needs. However, people generally cannot gratify sexual and other bodily desires whenever they wish. Instead, the drive to gratify bodily needs often conflicts with the dictates of society. Behavior, then, reflects a conflict between biological desires on the one hand and social constraints on the other. In psychoanalysis, the mind is said to contain different systems that serve different functions: satisfying bodily needs, representing social norms and rules, and striking a strategic balancing between biological drives and social constraints. An additional defining feature of psychodynamic theory is that much of this mental activity is said to occur outside of one's conscious awareness. We are not aware of the drives that underlie our emotions and behavior; they are unconscious.

Phenomenological theories, reviewed next (Chapters 5 and 6), contrast starkly with the psychodynamic view. Phenomenological theories are less concerned with

unconscious process and more concerned with people's conscious experience of the world around them, that is, their phenomenological experience. Phenomenological theorists recognize that people have biologically based motives, yet they believe that people also possess “higher” motives involving personal growth and self‐ fulfillment and that these motives are more important to personal well‐being than are the animalistic drives highlighted by Freud. Finally, compared to psychodynamic approaches, phenomenological theory places much greater emphasis on the self. The development of a stable and coherent understanding of oneself is seen as key to psychological health.

Trait approaches to personality, reviewed in Chapters 7 and 8, differ strikingly from both of the previous formulations. The differences reflect not only different views about the nature of personality, but also different scientific beliefs about the best way of building a personality theory. Most trait theorists believe that, to construct a theory of personality, one must begin by solving two scientific problems: (1) determining which individual differences are most important to measure and (2) developing a reliable measure of these individual differences. Once these problems are solved, one would be able to measure the most important individual differences in personality, and these measurements could serve as a basis for constructing a comprehensive theory of persons. A main development in the late‐20th‐century history of the field is that many personality psychologists came to conclude that these problems had, in fact, been solved. Much consensus has been achieved on the question of what individual differences are most important and on how they can be

Chapter 9 addresses one of the most exciting aspects of contemporary personality science, namely, research on the biological foundations of personality. This includes findings regarding the genetic bases of personality traits, as well as work revealing the brain systems that underlie individual differences. In this chapter, we devote coverage not only to trait theories but also to evolutionary psychology. Evolutionary psychologists explain contemporary patterns of social behavior in terms of mental mechanisms that are a product of our evolutionary past.

Chapter 10 introduces the ideas of behaviorism, which represent a learning approach to personality. In behavioral theories, behavior is seen as an adaptation to rewards and punishments experienced in the environment. Since different people experience different patterns of reward in different settings, they naturally developed different styles of behavior. Basic learning processes, then, are said to account for the stylistic variations in behavior that we call “personality.” Behaviorism presents a profound challenge to the theories presented previously. To the behaviorist, the units of analysis of the previous theories—the psychodynamic theorist's “unconscious forces,” the “self” of phenomenological theories, personality “traits”—are not causes of behavior. They merely are descriptions of patterns of thinking, emotion, and behavior that ultimately are caused by the environment that, according to the behaviorist, shapes our behavior.

Chapter 11 introduces a markedly different theoretical approach, that of personal construct theory. Personal construct theory addresses people's capacity to interpret the world. Unlike the behaviorist, who is most concerned with how the environment determines our experiences, the personal construct theorist studies the subjective ideas, or constructs, that people use to interpret the environment. One person may view the college environment as challenging, another as boring; one person may view dating circumstances as romantic, another as sexually threatening. Personal construct theorists explore the possibility that most individual differences in personality functioning stem from the different constructs that people use to interpret their world.

Chapter 14 considers personality in context. We explore contemporary research that illustrates the critical point that you often can learn much about people's personalities by studying the life contexts—the social situations, cultural settings, interpersonal relationships, and so on—that make up their life. This research heavily capitalizes on the social‐cognitive perspective discussed in Chapters 12 and 13, while providing a broad portrait of contemporary psychological research on social settings and the individual. We end, in Chapter 15 (available at the book’s website, www.wiley.com/go/cervone/personality14e), by critically evaluating the field of personality psychology as a whole.

The textbook takes advantage of contemporary knowledge in brain science. Today's personality psychologist has access to information about the brain that was

unavailable in the past, when the primary personality theories were developed. This knowledge enables us to reevaluate the personality theories from a contemporary brain‐science perspective. We'll do this throughout the book, in multiple chapters, in a feature called Personality and the Brain.

Finally, Personality: Theory and Research recognizes that theoretical innovation in this field did not cease at the end of the 20th century. Contemporary Developments sections, found in a number of chapters ahead, show you how current‐day psychologists have built upon the foundations established by earlier theorists.

The fact that this book presents these multiple theories might at first seem odd. Courses in most other scientific disciplines (e.g., chemistry, physics) are not organized around a series of different theories. Knowledge is organized by one commonly accepted conceptual framework. In part, this reflects the maturity of these other fields, which have been around longer than the science of psychology. Yet even the “mature sciences” may harbor different views of the same phenomenon. Suppose that you were to ask a physicist about the nature of light. You might learn that physics has a theory that says that light is a wave. And you might learn that physics also has a theory that says that light is composed of individual particles. If you were to ask “Which theory is right?”, you would be told “Neither”. Light acts as a wave and as a particle. Both a wave theory and a particle theory capture important information about the nature of light.

The same is true for the personality theories. Each captures important information about human nature. As you read about them, you should not be asking yourself “Which theory was right, and which ones are wrong?” Instead, it is better to evaluate them by asking how useful they are in advancing basic knowledge and applications. Even a theory that gets some things wrong may have much value (Proctor & Capaldi, 2001).

As we were preparing a recent edition of this textbook, a colleague suggested to us a useful metaphor for thinking about personality theories. It is useful because it moves one away from simplistic right/wrong evaluations and toward a more sophisticated view. She suggested that theories are like toolkits. Each theory contains a set of “tools”. Some of these tools are theoretical concepts. Others are

research methods. Some are techniques for assessing personality. Yet others are methods for doing therapy. Each element of the theory is a tool in that each serves one or more functions; each, in other words, enables one to carry out one or more jobs. The jobs are things like describing individual differences, identifying basic human motivations, explaining the development of self‐concept, identifying the causes of emotional reactions, predicting performance in work settings, or reducing psychological distress via therapy. These are jobs the psychologist wants to do. Each theory provides conceptual tools for doing them.

The toolkit metaphor has two benefits: It leads one (1) to ask good questions about personality theories and (2) to avoid asking bad ones. To see these benefits, imagine that you are evaluating actual physical toolkits. If you saw a plumber, an electrician, and an auto mechanic each carrying a toolkit of their profession, you would not go up to any of them and say “Your toolkit is wrong.” The idea that a toolkit could be wrong hardly makes sense. A toolkit may be less good than another for doing a particular job. It may be less useful for a range of jobs than some other toolkit that contains more tools. It may be more practical than some other toolkit that contains more tools because the larger toolkit is unwieldy. You would evaluate toolkits by asking about what you can do with them and how they might be improved by adding, or sometimes removing, tools. You would not evaluate them by asking “Which one is correct?”

Similarly, when evaluating the different personality theories we present, we encourage you to ask questions such as “What can one do with the conceptual tools of this theory?” “What advantages do its conceptual tools have in relation to other theories?” or “What tools could be added to (or subtracted from) the theory to make it better?” These questions are better than asking “Which theory is right?”

The toolkit metaphor has a final implication. It suggests that the existence of multiple theories in contemporary personality psychology might not be such a bad thing. In the world of actual physical tools, when people have different toolkits they might learn new things from one another. They might add a tool from someone else's kit or be inspired to attempt someone else's job with the tools they have. In the long run, the diversity among toolkits may improve everyone's work.

The same may be true in the world of theoretical tools. When multiple theories exist, investigators are more likely to face research findings and theoretical arguments that challenge their favored view. The challenges may prompt them to refine, extend, and ultimately improve their own thinking. Theoretical diversity thus can accelerate the overall progress of a discipline.

We hope you enjoy your tour through the erratic, but progressing, enterprise of personality theory and research.

We all think about personality in our day‐to‐day lives. The work of personality theorists differs from this everyday thinking in that personality theories pursue five goals that are uncommon in everyday thinking about persons. They engage in (1) scientific observations that underlie theories that are (2) internally coherent and systematic, (3) testable, and (4) comprehensive, and that foster (5) useful applications.

Personality theories address what, how, and why questions about personality by developing theories that address four distinct topics: (1) personality structure, (2) personality processes, (3) personality development, and (4) personality change (including via psychotherapy).

Personality theorists have confronted a range of issues throughout the history of the field. In developing theories that encompass these issues, the theorist hopes to develop a framework that serves three scientific functions: (1) organizing existing knowledge about personality, (2) fostering new knowledge on important issues, and (3) identifying new issues for study.

The existence of multiple theories in the field can be understood by thinking of theories as toolkits, each of which provides unique conceptual tools for doing the jobs of the personality psychologist.