PAIC01 3/13/07 11:43 Page 1 Introducing Individual Differences: From Everyday to 1 Psychological Questions Chapter Outline 1.1 INTRODUCTION 1.2 PERSONALITY: A COMMONSENSE IDEA 1.3 DESCRIBING INDIVIDUALS 1.4 ABNORMALITY 1.5 INTELLIGENCE, COMPETITION, AND ADAPTATION 1.6 PREDICTING SUCCESS 1.7 BORN DIFFERENT? 1.8 OTHER ABILITIES 1.9 VARIABILITY AND CHANGE: MOTIVATION AND MOOD STATES 1.10 CREATIVITY 1.11 LEADING THE WAY 1.12 INTERESTS 1.1 INTRODUCTION area in psychology. Whereas most psychological theories pretty much assume that everybody is the same and hence attempt The study of individual differences is part of a well-established to identify the universal aspects of human behavior, individual tradition in psychology that dates back more than a century. It difference theories are concerned with differences between people, encompasses several non-observable or “latent” constructs, such or what makes everyone unique. as intelligence and personality, which represent major sources of For example, cognitive psychologists may try to explain the variation in behavior. This makes individual differences a unique processes underlying short-term memory, whereas intelligence .. PAIC01 3/13/07 11:43 Page 2 2 Introducing Individual Differences Chapter 2 PERSONALITY: History, definitions, approaches, and structure Chapter 3 PERSONALITY: Traits in everyday life: what do they predict? Chapter 4 PSYCHOPATHOLOGY: Abnormal behavior and mental illness Chapter 5 INTELLIGENCE: Measurement of human abilities, IQ tests Chapter 6 INTELLIGENCE: In everyday life, what does intelligence predict? Chapter 7 BEHAVIORAL GENETICS: Genetic and environmental influences Chapter 8 BEYOND IQ: Searching for novel abilities (social, emotional, etc.) Chapter 9 MOOD AND MOTIVATION: Differences within individuals Chapter 10 CREATIVITY: Relationship to personality and intelligence Chapter 11 LEADERSHIP: Situational, personal, and interactional theories Chapter 12 INTERESTS: Rediscovering the importance of vocations Figure 1.1 Book contents at a glance. researchers may explain why some people have better short-term Although the boundaries of differential psychology are yet to be memory than others (Deary, 2001). Social psychologists may established, the label “individual differences” is normally used to explain obedience to authority (Milgram, 1963), whilst personal- refer to personality and intelligence. Accordingly, half of this ity theories may tell us why some people are more obedient than book is, in one way or another, dedicated to these variables (see others (Adorno, Frenkel-Brunswick, Levinson, & Sanford, 1950). chapters 2, 3, 5, 6, 7, and 8). But personality and intelligence are Educational psychologists may assess the impact of anxiety on not sufficient to explain differences between individuals, and the learning (Darke, 1988), whereas personality researchers may study of individual differences involves more than personality assess an individual’s likelihood of experiencing anxiety (Zeidner, and intelligence theories. Thus, this book also covers psycho- 1998). Neuropsychologists may test whether recreational drugs, pathology or abnormal behavior (chapter 4), motivation and such as Ecstasy, have long-term effects on individuals’ level of mood states (chapter 9), creativity (chapter 10), leadership aggressiveness, whereas differential psychologists may investigate (chapter 11), and interests (chapter 12). An overview and basic which individuals are more likely to use recreational drugs and description of the chapters is presented in Figure 1.1. why (Zuckerman, 1994). The goal of individual difference researchers, then, is to identify the most general aspects underlying individuality and concep- 1.2 PERSONALITY: tualize a theoretical classification for predicting differences and A COMMONSENSE IDEA similarities in human thought, emotionality, and behavior. Simply put, individual difference researchers are concerned with explain- Differential psychology aims to explain observable differences ing how and why people are different from one another, and aim between individuals in terms of underlying psychological deter- to achieve a wide understanding of the psychological processes minants. This implies that certain psychological differences, in that determine such differences. the way people feel or think, lead to manifest differences Throughout this chapter, I introduce the topic of individual in the way they act. To this end, differential psychologists differences from the perspective of real-life problems. In other collect enormous amounts of information on how people words, I use a commonsense approach to explore the longstand- behave, paying particular attention to their consistent beha- ing psychological questions that gave rise to the academic area vioral patterns, and establish comparisons between different of individual differences that is known as differential psychology. people. This enables them to predict an individual’s likelihood .. .. PAIC01 3/13/07 11:43 Page 3 Introducing Individual Differences 3 behavior: e.g., goes partying a) different people have different interests b) different interests determine awareness different behaviors and intention c) we are aware, as actors and observers, of these interests interests: preferences: and behaviors e.g., likes e.g., meeting d) people tend to act in a parties people consistent manner values: e.g., having fun Figure 1.2 Traits as dispositions to act according to interests, values, and preferences. of behaving in one way or another. Take, for instance, the and other-observation. Last but not least, the examples suggest that following examples. people tend to act in a consistent manner, that is, that there are specific patterns of behavior that are common or frequent in • Chloe is 21 and loves partying. She has many friends and some individuals, but strange or infrequent in others. an active social life. She prefers the company of others to In brief, the above examples suggest that (1) different people studying or reading, and is easily bored staying at home. may have different interests, values, and preferences; (2) people’s • Laura, also 21, spends most weekends at home, reading interests, values, and preferences are reflected in their beha- and writing. She hates loud parties and dislikes talking to viors; (3) we are aware, as actors and observers, of these interests, strangers. She enjoys spending time with her family and a few values, and preferences; (4) people tend to act in a somewhat close friends, but makes no effort to meet other people. consistent manner across space and time (see Figure 1.2 for a graphical representation of these assumptions). All these assump- Now, considering the information you have about Chloe and tions are at the center of individual difference research, in particu- Laura, try to answer the following questions: lar theories of personality traits, which are the focus of chapters 2 and 3. a) Are you more similar to Chloe or Laura? b) What about your friends? Are they more similar to Chloe or Laura? 1.3 DESCRIBING INDIVIDUALS c) How would you describe Chloe and Laura? d) What else would you need to know about Chloe and Laura Theories of personality conceptualize behavioral differences in to know what they are like? terms of wide psychological characteristics or traits (see chap- e) Why are Chloe and Laura different? ter 2), which are partly inherited and remain relatively stable throughout lifespan, especially after adulthood. In the same There are several assumptions underlying the above examples. way that we can describe individuals according to their physical First, we can see that individuals, even of the same age and characteristics (e.g., tall, blond, slim, fat, pale), personality theor- gender, have different interests (e.g., reading, going out, meeting ists have attempted to develop a classification or taxonomy of new people). Second, these interests may determine the way they individuals in terms of their psychological characteristics (e.g., usually behave, that is, their choices of behavior across a range of extraverted, conscientious, agreeable, shy). situations. Thus, if Chloe loves going to parties, she will be more In that sense, the first aim in putting forward the concept of likely to go partying than if she hated parties (as in Laura’s case). personality traits is descriptive, that is, to identify the major pat- Third, and following on from the second point, we can see that terns of behavior by which people can be compared. In physical an idea implicit in the above examples is that individuals are terms, we can compare individuals by their height, weight, color aware of what they like and dislike. Not only are actors (e.g., of hair, skin, and so on, and in fact there are as many behavioral Chloe and Laura) aware, but so too are observers (whoever is aspects of individual differences as there are physical ones. describing others’ behavior). We are therefore faced with two However, whilst it is easy to observe differences in physical perspectives for assessing differences in behavior, namely, self- complexity, it is difficult to observe differences in psychological .. .. PAIC01 3/13/07 11:43 Page 4 4 Introducing Individual Differences motives underlying criminal offenders. People in general may abnormal clinical want to know which men or women are compatible with them behavior for establishing friendships and business or romantic relation- ships. Furthermore, knowing what others like and dislike may help us relate to others, and knowing what others are like may understand