Personality Traits PDF

personality traits of his partner. “I was more interested in people’s values and activities,” he says. “After all, how people act so often depends on the situations they find themselves in, and how they view those situ...

personality traits of his partner. “I was more interested in people’s values and activities,” he says. “After all, how people act so often depends on the situations they find themselves in, and how they view those situations.” From choosing life partners, to describing our friends and enemies, to understanding ourselves, we appeal to the notion of personality. But are we really the same person across situations, or do we act differently at different times? Amanda, for example, chats with strangers on the subway, but finds herself subdued in museums and places of worship. Likewise, John is often soft-spoken with his grandparents, but loud and commanding with his two younger brothers. “Those roughnecks need to know who’s in charge,” he jokes. But can we change our personalities entirely? Can others change us? John says that marriage has made him more conscientious, although he admits to carrying an electronic calendar to compensate for his dispositional lateness. Amanda points out, though, that John believes he can change more than she believes she can change. “I usually just try to accept my personality quirks,” she says. “He tries to be a better person every day.” Where do personalities come from, anyway—our genes, our experiences, or both? Amanda’s mother says that Amanda “was born early, and has been early to everything ever since.” Amanda notes, however, that her mother wouldn’t have tolerated anything else: “She’s done with her Christmas shopping by September, and expects her children to be, also.” And so Amanda’s experiences with her family enhanced her seemingly inborn inclination to be conscientious. Meanwhile, John notes that he was an introverted child, but acting brought out his extraverted side. People differ in many ways, including their desires, feelings, and behavior, their views of themselves and others, and their outlooks on the world. Some people are a delight; others are obnoxious. Some like to be with a crowd; others prefer to be alone. These distinctions and many others fall under the heading of personality, an area of psychology that describes how people differ and explores how the many aspects of each person come together. As it turns out, this is an undertaking so ambitious that no one approach provides a completely satisfying account of all of personality. In this chapter, therefore, we describe four different approaches to personality and show how each focuses on a different part of the puzzle of who we are. THE TRAIT APPROACH: DEFINING OUR DIFFERENCES The trait approach to the study of personality assumes that the differences among traits Relatively stable patterns of people can be captured by talking about what traits a person has—whether he is friendly thought, feeling, or behavior that or not, helpful or not, formal or not. Unlike states, which are temporary (e.g., being characterize an individual. angry at this moment), traits are relatively enduring (e.g., being generally hot-headed), states Temporary patterns of and, as a result, trait labels allow us to summarize what someone is like, often in a single thought, feeling, or behavior. word, and serve as a basis for making predictions about what she is likely to do in the future. The trick, however, is to figure out which traits to use in forming a description of a person that succinctly captures who he is but also is precise enough to predict his actions. Think about one of your close friends. How would you describe this person to others? Shy? Confident? Bashful? Fun-loving? Upbeat? Notice how many words come to mind. Indeed, if we want to describe how people differ from one another, we seem to 592 chapter 15 PPERSONALITY O have a nearly endless supply of terms to work with. But do we really need all of these terms? Or can we reduce the list, perhaps by eliminating redundant or rarely used terms, to reveal a (much smaller) set of basic personality traits? The Big Five An unabridged English dictionary contains almost 18,000 personality-relevant terms (Allport & Odbert, 1936). To reduce this list to manageable size, early trait theorists put many of these words to the side simply because they were synonyms, slang, or just uncommon words. Raymond Cattell, one of the pioneers in this arena, gave this kind of shortened list of words to a panel of judges, asking them to use these words to rate a group of people they knew well (Cattell, 1957). Their ratings were compared to find out which terms were redundant. This process allowed Cattell (1966) to eliminate the redundant terms, yielding what he thought were the 16 primary personality dimensions. Subsequent investigators presented evidence from further analyses that several of Cattell’s dimensions still overlapped, so they reduced the set still further. A few investigators, such as Hans Eysenck (1967), argued that just two dimensions were needed to describe all the variations in personality, although he later added a third. Others argued that this was too severe a reduction, and, over time a consensus has emerged around five major personality dimensions as the basis for describing all personalities; this has led to a personality system appropriately named the Big Five Big Five Five crucial dimensions of (D. W. Fiske, 1949; Norman, 1963; Tupes & Christal, 1961). personality determined through factor The Big Five dimensions are extraversion (sometimes called extroversion), analyses of trait terms: extroversion, neuroticism (or emotional instability), neuroticism (sometimes labeled with its positive pole, emotional stability), agreeableness, agreeableness, conscientiousness, and conscientiousness, and openness to experience (L. R. Goldberg, 2001; John & Srivastava, openness to experience. 1999; McCrae & Costa, 2003).* These dimensions seem useful for describing people from childhood through old age (Allik, Laidra, Realo, & Pullman, 2004; McCrae & Costa, 2003; Soto, John, Gosling, & Potter, 2008) in many different cultural settings (John & Srivastava, 1999; McCrae & Costa, 1997; McCrae & Terracciano, 2005; Yamagata et al., 2006). The Big Five traits even seem useful in describing the personal- ities of other species, including chimpanzees, dogs, cats, fish, and octopi (Gosling, 2008; Gosling & John, 1999; Weiss, King, & Figueredo, 2000). What do these dimension labels mean? Extraversion means having an energetic approach toward the social and physical world. Extraverted people often feel positive emotion and tend to agree with statements like “I see myself as someone who is outgo- ing, sociable,” while people who are introverted (low in extraversion) tend to disagree with these statements. (This and the following items are from the Big Five Inventory: John, Donahue, & Kentle, 1991). Neuroticism means being prone to negative emotion, and its opposite is emotional stability. This dimension is assessed by finding out whether people agree with statements like “I see myself as someone who is depressed, blue.” Agreeableness is a trusting and easygoing approach to others, as indicated by agreement with statements like “I see myself as someone who is generally trusting.” Conscientiousness means having an organized, efficient, and disciplined approach to life, as measured via agreement with statements like “I see myself as someone who does things efficiently.” Finally, openness to experience refers to unconventionality, intellectual curiosity, and interest in new ideas, foods, and activities. Openness is indicated by agreement with statements like “I see myself as someone who is curious about many different things.” *To remember the Big Five, Oliver John (1990) suggests the mnemonic OCEAN. PThe Trait Approach: Defining Our DifferencesO 593.80 Notice that the Big Five—like Cattell’s initial set of 16 dimen- sions—is cast in terms of personality dimensions, and we identify someone’s personality by specifying where he falls on each dimen-.60 sion. This allows us to describe an infinite number of combinations, or, to put it differently, an infinite number of personality profiles Correlation.40 created by different mixtures of the five basic dimensions. MEASUREMENT AND MEANING.20 As we will see throughout this chapter, personality theorists rely on many different types of data. To measure where a person stands on 0 each of the Big Five dimensions, researchers typically use self- cism ess ion s ess nes report data, employing measures such as Costa and McCrae’s NEO- ers usn enn roti ble PI-R (1992)—asking people in essence to describe themselves, or to rav ntio eea Op Neu indicate how much they agree with proposed statements that might Ext scie Agr describe them. Self-report measures assume, though, that each of us Con (A) (B) knows a great deal about our own beliefs, emotions, and past 15.1 Reading personality from a actions, and so can describe ourselves. But is this assumption correct? What if people bedroom Researchers have found that lack either the self-knowledge or the honesty required for an accurate self-report reliable personality ratings can be based on (Dunning, Heath, & Suls, 2004)? quite limited information. For example, To find out, one option is to collect data not just from the people we are interested in, Sam Gosling and colleagues have demon- but also from others who know these people well. These informant data can come from strated that Big Five personality ratings parents, teachers, coaches, camp counselors, fellow parishioners, and so on (Figure 15.1). may be made reliably on the basis of (A) a person’s bedroom as shown by (B) correla- Though informants’ perspectives are not perfect, they provide another important win- tions between observers’ ratings and com- dow onto the person, and across studies researchers have found that self-report and bined self- and peer-ratings of the rooms’ informant data generally agree well in the case of ratings of the Big Five (McCrae & occupants (Gosling, Ko, Mannarelli, & Costa, 1987). It seems, then, that most people do know themselves reasonably well—a Morris, 2002). point that is interesting for its own sake, and also makes our assessment of traits rela- tively straightforward. No matter how they’re measured, the Big Five dimensions are probably best concep- self-report data Data supplied by tualized in hierarchical terms, as shown in Figure 15.2. This figure presents just one of the research participant describing the Big Five dimensions, extraversion, and shows that this dimension is really a broad herself (usually, ratings of attitudes or summary of many more specific facets of personality. Each of these facets in turn is moods, or tallies of behavior), rather made up of even more specific behavioral tendencies, which are themselves made up than that collected by the of specific behaviors. If we choose terms higher in the hierarchy (e.g., the Big Five experimenter. themselves), we gain a more economical description with fewer, broader terms. informant data Data about a person At the same time, though, if we choose terms lower in the hierarchy, we gain accu- derived from others who know the racy, with the traits providing a more direct and precise description of each person’s person well. behavior (John & Srivastava, 1999). Thus, for example, if we want to predict how a new Extraversion 15.2 The hierarchical organization of Facets Sociable Lively Active Assertive Sensation -seeking personality One of the Big Five personal- ity traits, extraversion, encompasses a broad summary of many more specific Behavioral tendencies facets of personality, each of which is defined by particular behavioral tenden- Specific cies and still more specific behaviors. behaviors 594 chapter 15 PPERSONALITY O employee will perform on the job, or predict how well a nurse will perform under stress, we might want more than the overarching description provided by the Big Five itself; we might want to zoom in for a closer look at the way the Big Five traits can manifest themselves in a particular individual. One way to do this is to use the Q-Sort, a set of 100 brief descriptions that a rater sorts into a predetermined number of piles, corresponding to the degree to which they describe a person (Block, 2008). There are also hundreds of more-specific measures available, each seeking to describe a particu- lar aspect of who someone is and how he or she behaves. CULTURAL DIFFERENCES Cattell and the Big Five theorists developed their personality factors in English, and they used mostly middle-class English-speaking subjects to validate their theories. As discussed in Chapter 13, though, cultures differ in how they view human nature. Are the Big Five dimensions equally useful as we move from one culture to the next? We have already alluded to the fact that the Big Five dimensions do seem to describe personalities in a wide range of cultures. More precisely, as we move from one culture to the next, we still find that the trait labels people use to describe each other can be “boiled down” to the same five dimensions (McCrae & Costa, 1997; McCrae & Terracciano, 2005). There are, however, reasons to be cautious about these findings. As one concern, instead of allowing natives of a culture to generate and organize personality terms themselves (Marsella, Dubanoski, Hamada, & Morse, 2000), most researchers simply administer a test that was already developed using English-speaking subjects. This approach may not allow people’s natural or routine understandings to emerge (Greenfield, 1997), and so, even if these studies confirm the existence of the Big Five dimensions in a population, they do not show us whether these are the most frequently used categories in that culture, or whether they are useful in predicting the same behaviors from one culture to the next. In fact, when participants have been allowed to generate personality terms on their own, support for the cross-cultural generality of the Big Five has been mixed. For example, when researchers explored the personality traits used by Hong Kong and mainland Chinese samples, they found four factors that could be related to the Big Five, but one factor that seemed to be uniquely Chinese, which reflected interpersonal relatedness and harmony (Cheung, 2004; Cheung & Leung, 1998; see Figure 15.3). In Spanish samples, seven factors seem best to describe personality (Benet-Martinez, 1999), five of which map reasonably well onto the Big Five. Other researchers have found three factors in Italian samples (Di Blas, Forzi, & Peabody, 2000), and nine fac- tors bearing little resemblance to the Big Five were used by students in Mexico (La Rosa & Diaz-Loving, 1991). Thus, although the Big Five seem to be well established 15.3 Culture and personality Interpersonal among many cultures, there is room for debate about whether these dimensions are relatedness and harmony are particularly truly universal. important in China. The Consistency Controversy Whether they endorse the Big Five dimensions or not, trait theorists agree that individ- uals’ personalities can be described in terms of stable and enduring traits. After all, when we say that someone is friendly and warm, we are doing more than describing how he acted on a particular occasion. Instead, we are describing the person and, with that, providing some expectations about how he will act on other occasions, in other settings. But is this right? Is someone’s behavior stable in this way? PThe Trait Approach: Defining Our DifferencesO 595  HOW CONSISTENT ARE PEOPLE? In one classic study, researchers examined the behavior of schoolchildren—and, in par- ticular, the likelihood that each child would be dishonest in one setting or another (Hartshorne & May, 1928). Quite remarkably, the researchers found little consistency in children’s behavior: Children who were inclined to cheat on a school test were often quite honest in other settings (e.g., an athletic contest), and vice versa. Based on these findings, it would be misleading to describe these children with trait labels like “honest” or “dishonest”—sometimes they were one, and sometimes the other. Some 40 years ago, Walter Mischel reviewed this and related studies, and concluded that people behave much less consistently than a trait conception would predict, a state personality paradox The idea that of affairs which has been referred to as the personality paradox (Mischel, 1968). Thus, people seem to behave much less for example, the correlation between honesty measured in one setting and honesty consistently than a trait conception measured in another situation was.30, which Mischel argued was quite low. Mischel would predict. noted that behaviors were similarly inconsistent for many other traits, such as aggres- sion, dependency, rigidity, and reactions to authority. Measures for any of these, taken in one situation, typically do not correlate more than.30 with measures of the same traits taken in another situation. Indeed, in some studies, there is no detectable corre- lation at all (Mischel, 1968; Nisbett, 1980). These findings led Mischel to conclude that trait conceptions of personality dramatically overstate the real consistency of a person’s behavior. WHY AREN’ T PEOPLE MORE CONSISTENT ? How should we think about these results? One option is to argue that our personalities are, in fact, relatively stable just as the trait approach suggests, but acknowledge that situations often do shape our behavior. Given a red light, most drivers stop; given a green light, most go—regardless of whether they are friendly or unfriendly, stingy or generous, dominant or submissive. Social roles likewise often define what people do independent of their personalities. To predict how someone will act in a courtroom, for example, there is little point in asking whether he is sociable, careless with money, or good to his mother. What we really want to know is the role that he will play—judge, prosecutor, defense attorney, or defendant. In Chapter 13 we reviewed studies indicating that the influence of a situation can be incredibly powerful—leading ordinary college students to take on roles in which they are vicious and hurtful to their peers. It’s no wonder, then, that there is sometimes lit- tle correspondence between our traits and our behavior and less consistency in our behavior than the trait perspective might imply. The reason, in brief, lies in what’s called the power of the situation. Because of that power, our behavior often depends more on the setting we are in than on who we are. Sometimes, though, our behavior does depend on who we are. Particularly in weak situations—ones in which the environment provides few guides for our behavior—our personalities shape our actions (Figure 15.4). Even in strong situations—ones in which the environment provides clear guides for our behavior—different people react to the situation in somewhat different ways, so that their behavior in the end reflects the inter- action of the situation with their personality (Fleeson, 2004; Magnusson & Endler, 1977). Moreover, it’s not a matter of chance how a particular person reacts to this situation or that one; instead, people seem to be relatively consistent in how they act in certain types of situations. Thus, for example, someone might be punctual in profes- sional settings, but regularly late for social occasions; they might be shy in larger groups, but quite outgoing when they are with just a few friends. 596 chapter 15 PPERSONALITY O  15.4 Weak and strong situations (A) An example of a weak situation is a casual party where different people behave quite differently. (B) An example of a strong situ- ation is an examination, where very similar behavior is seen across individuals. (A) A weak situation (B) A strong situation Evidence for these points comes from many sources, including a study in which chil- dren in a summer camp were observed in a variety of situations—settings, for example, in which they were teased or provoked by a peer, or settings in which they were approached in a friendly way by a peer, or settings in which they were scolded by an adult (Cervone & Shoda, 1999; Mischel, Shoda, & Mendoza-Denton, 2002). In this study, the researchers relied on behavioral data—data based on observations of specific actions— behavioral data Data about a per- and these data showed that each child’s behavior varied from one situation to the next. son based on direct observation of For example, one child was not at all aggressive when provoked by a friend, but that person’s actions or behavior. responded aggressively when scolded by an adult. Another child showed the reverse pat- Self-Monitoring Scale A personality tern. Thus, the trait label aggressive would not consistently fit either child—sometimes measure that seeks to determine the they were aggressive and sometimes they were not. degree to which a person alters or There was, however, a clear pattern to the children’s behavior, but the pattern emerges adjusts their behavior in order to act only when we consider both the person and the situation. As the investigators described appropriately in new circumstances. it, the data suggested that each of the children had a reliable “if... then...” profile: “If in this setting, then act in this fashion; if in that setting, then act in that fashion” (Mischel et al., 2002). Because of these “if... then...” patterns, the children were, in fact, reason- ably consistent in how they acted, but their behaviors were “tuned” to the situations they found themselves in. Thus, we need to be careful when we describe any of these children as being “friendly” or “aggressive” or “helpful,” relying only on global trait labels. To give an accurate description, we need to be more specific, saying things like “tends to be friendly in this sort of setting,” “tends to be helpful in that sort of setting,” and so on. ARE SOME PEOPLE MORE INFLUENCED BY THE SITUATION THAN OTHERS? There is one more complexity we must keep in mind as we consider how personality and situations interact to shape behavior. Some individuals are more consistent than others across situations, or, turning this around, some individuals are more flexible than others. This difference among people is assessed by the Self-Monitoring Scale, developed by Mark Snyder and designed to assess the degree to which people are sen- sitive to their surroundings and likely to adjust their behaviors to fit in. The scale includes items such as “In different situations and with different people, I often act like very different persons.” High self-monitors care a great deal about how they appear to others, and so, at a cocktail party, they are charming and sophisticated; in a street basketball game, they “trash talk.” In contrast, low self-monitors are less interested in how they appear to PThe Trait Approach: Defining Our DifferencesO 597 15.5 The extremes of the self-monitor- ing scale (A) Matt Damon as Tom Ripley in The Talented Mr. Ripley: the high self-moni- tor, who can fit in with anybody, anywhere, anytime. (B) Heath Ledger as the Joker in The Dark Knight: the ultimate low self-mon- itor, who stays true to himself regardless of the situation. (A) (B) others. They are who they are regardless of the momentary situation, making their behavior much more consistent across situations (Figure 15.5; Gangestad & Snyder, 2000; M. Snyder, 1987, 1995). This suggests that the extent to which situations deter- mine an individual’s behavior varies by person, with situations being more important determinants of high self-monitors’ behavior than of low self-monitors’ behavior. How consistent individuals are also varies at the cultural level of analysis. Americans, for example, are relatively consistent in how they describe themselves, no matter whether they happen at the time to be sitting alone, next to an authority figure, or in a large group (Kanagawa, Cross, & Markus, 2001). By contrast, Japanese partici- pants’ self-descriptions varied considerably across contexts, and they were far more self-critical when sitting next to an authority figure than when they were by themselves. There also cultural differences in how consistent individuals want to be. In one study, researchers asked American and Polish participants how they would respond to a request to take a survey about beverage preferences. When asked to imagine they had previously agreed to such requests, American participants said they would again agree to the request—apparently putting a high value on self-consistency. Polish partici- pants, by contrast, were much less concerned with self-consistency, and so were less influenced by imagining that they had agreed to similar requests in the past (Cialdini, Wosinka, Barrett, Butner, & Gornik-Durose, 1999). Traits and Biology Where does all of this leave us? Plainly, situations do matter in shaping how we act, and, as a result, we can easily document inconsistencies in how someone behaves: She might be honest in one setting but treacherous in another, friendly in one situation but hostile otherwise, with her behavior in each case governed as much by where she is as by who she is. At the same time, we can also document ways in which each of us is consistent in who we are. We shouldn’t be surprised, therefore, that personality traits have been shown to predict important life outcomes (Ozer & Benet-Martinez, 2006; Roberts, Kuncel, Shiner, Caspi, & Goldberg, 2007). For example, the Big Five personality dimensions are related to outcomes ranging from career success (Barrick,Mount,& Gupta,2003) to crim- inal activities (Wiebe, 2004) to health and mortality (Roberts, Walton, & Bogg, 2005). Personality consistency thus seems to be alive and well, especially if we understand trait labels to be descriptions of how a person tends to act in a certain sort of situation, rather than a description of what he is like at all times and in all places. However, this simply leads to a new question: Given that people do differ in their personalities, how do these differences arise? 598 chapter 15 PPERSONALITY O GENES AND PERSONALITY Mounting evidence suggests that personality traits grow out of the individual’s temperament, a characteristic pattern of emotion, attention, and behavior that is temperament A person’s character- evident from an early age and is determined to a considerable degree by genetic pat- istic level of reactivity and energy; terns (Kagan, 1994; Rothbart & Bates, 2006; Thomas & Chess, 1977). Evidence for often thought to be constitutional. this genetic influence—both on temperament and on personality in general—comes from the same methods used to study heritability in other contexts, including stud- ies of twins (monozygous or not, raised separately or apart) and studies of adoptees (Figure 15.6). Data from these studies tell us that in just about all cases, identical twins turn out to be more alike than fraternal twins on various personality attributes (see A. H. Buss & Plomin, 1984; Zuckerman, 1987a). For example, one study com- pared the personalities of 123 pairs of identical twins and 127 pairs of fraternal twins and found that heritability for the Big Five personality dimensions ranged from 40 to 60% (Borkenau, Riemann, Angleitner, & Spinath, 2001; Jang, Livesley, & Vernon, 1996; Loehlin, 1992). Peculiarly, though, genetic influences have also been identified for much more specific traits such as television watching, traditionalism, and the willingness to divorce (Bouchard, Lykken, McGue, Segel, & Tellegen, 1990; McGue & Lykken, 1992; Plomin, Corley, DeFries, & Fulker, 1990). In each case, there is a greater resemblance between identical twins with regard to these traits than between fraternal twins. Of course, natural selection unfolds at a slow pace, but television has existed for less than a century. Therefore, the genetic influence on these kinds of tendencies may reflect the operation of other, more general personality dimensions—such as those named in the Big Five. For example, television watching may be associated with extraversion, and traditionalism with conscientiousness. Likewise, in a study of adult twins, those twins who divorced had higher average scores on measures related to extraversion and neuroticism, and lower scores on measures of impulse control (Jockin, McGue, & Lykken, 1996). This is certainly consistent with the idea that the specific trait (tendency to divorce) is derived from the more general biologically based tendencies such as extraversion or neuroticism, and it is the latter that are influenced by the genes. 0.7 Monozygotic Correlation between twin pairs 0.6 Dizygotic 0.5 0.4 15.6 The similarity of twins (A) Identical 0.3 twins Fred and Don Lamb are both 0.2 astrophysicists (although with different 0.1 specialties), and both have been enor- mously successful in their careers. (B) The 0 greater similarity between identical twins ion ism s s ss es s ne ne than between fraternal twins suggests to rs len tic us en ve uro ab many that personality, ability, and interests o Op tra nti ree Ne Ex are all shaped by inheritance (since, after cie Ag ns all, identical twins have the same genetic Co (A) (B) pattern). PThe Trait Approach: Defining Our DifferencesO 599  PHYSIOLOGY AND PERSONALITY If our personalities have a basis in our genes, what exactly do the genes code for? Using physiological data Data about a physiological data, psychologists are beginning to explore how people with different person derived from measurement of personality traits differ in their biological functioning, with the hope that these data biological structures and processes. will offer a glimpse into how our genes shape who we are. sensation seeking A predisposition One example of this work is inspired by Hans Eysenck’s theory of extraversion/ to seek novel experiences, look for introversion. Eysenck proposed that the observable difference in personality derives thrills and adventure, and be highly from the fact that introverts react more strongly than extraverts to external stimuli susceptible to boredom. (M. W. Eysenck, 1987). As a result, he argued, introverts often guard against stimula- tion from the outside, which to them feels like overstimulation. This is why, for exam- ple, introverts shy away from social settings—the stimulation in that setting would be more than they are comfortable with. It also turns out that introverts have a lower tol- erance for pain (Bartol & Costello, 1976), and, when they are studying, they prefer less noise and fewer opportunities for socializing (J. B. Campbell & Hawley, 1982). Can we confirm this proposal through studies of the brain? In one study, investiga- tors measured how people’s brain stems reacted when the people heard clicking noises. In line with Eysenck’s theory, introverts showed a quicker response than extraverts, indicating more reactive brain stems (Bullock & Gilliland, 1993; also see Kumari, Ffytche, Williams, & Gray, 2004). Similar arguments may help us to understand a more specific trait, sensation seeking, which refers to the tendency to seek varied and novel experiences, to look for thrills and adventure, and to be highly susceptible to boredom (Zuckerman, 1979, 1994; Figure 15.7). People high in sensation-seeking are more likely to participate in risky sports; to get more restless in monotonous, confined situations; and to drive faster than people with low sensation-seeking scores (Zuckerman, 1979, 1983). What leads to this pattern of behavior? One suggestion is that sensation seekers are people whose neurotransmitter systems (especially those relying on norepinephrine and dopamine) are underreactive. As a result, these people are chronically underaroused, and this makes them seek thrills and take risks to jog their sluggish neurotransmitter systems into greater activity (Zuckerman, 1987b, 1990, 1994). Consistent with this hypothesis, sensation seekers seem to be at greater risk for abusing drugs that influence dopamine lev- els. Researchers explain this finding by suggesting that in this case, the sensation seekers are using drugs, rather than activities such as sky diving or snake handling, to activate their underactive brain systems (Bardo, Donohew, & Harrington, 1996). These findings are buttressed by those of researchers who have developed a “rat model” of drug use. 15.7 Sensation seeking Some people actively seek thrills and arousal; others seek quiet activities. This difference in personality may derive from the responsiveness of the person’s nervous system. 600 chapter 15 PPERSONALITY O Using this model, researchers have shown that high levels of sensation seeking (measured by animals’ activity levels in a novel environment) predict the animals’ propensity to give themselves cocaine (Belin, Mar, Dalley, Robbins, & Everitt, 2008). Sensation seeking is common among extraverts; a very different pattern—called inhibited temperament—is associated with introversion and neuroticism (Fox, inhibited temperament A personal- Henderson, Marshall, Nichols, & Ghera, 2005; Kagan, 1994, 2003; Kagan & Snidman, ity style associated with introversion 1991; Putnam & Stifter, 2005). As infants, people with inhibited temperaments tend to and neuroticism, and characterized by a fear of novelty that is evident early in react strongly when they are distressed, crying vigorously and showing high levels of life. motor activity. As young children, inhibited individuals are unwilling to approach novel stimuli or people, become anxious in new situations, and frequently seek reassurance from their caregivers. Adolescents and adults who were categorized as inhibited at an early age are much less likely than others to be outgoing and socially spontaneous. The explanation for inhibited temperament may mirror the account of sensation seeking, and in particular may be associated with an overreactive brain (and attempts to compensate for this) just as sensation seeking is associated with an underreactive brain. Specifically, Kagan and colleagues hypothesize that inhibited children have a low threshold for activity in the amygdala, a subcortical brain structure crucial for detecting important stimuli in the environment. This hypothesis was tested using an fMRI study of young adults who had been classified when they were infants as either inhibited or uninhibited (Schwartz, Wright, Shin, Kagan, & Rauch, 2003; Figure 15.8). These participants viewed a series of familiar and unfamiliar faces. As predicted, when the inhibited participants viewed unfamiliar faces, their amygdalae showed higher levels of activation than did the amygdalae of uninhibited participants. The two groups did not differ, however, when they were viewing familiar faces, suggesting that it was the newness of the faces that led the inhibited individuals’ amygdalae to respond more strongly. 15.8 SCIENTIFIC METHOD: Do inhibited individuals have lower thresholds for activation in the amygdala? Method Results 1. Adult participants had been When viewing novel faces, adults previously classified as inhibited showed greater activations in classified either as inhibited or their amygdalae than those classified as uninhibited. This difference was markedly reduced uninhibited at age two. with familiar faces. 0.7 Inhibited Amount of amygdala action 0.6 2. Participants first saw six Uninhibited different faces presented 0.5 Amy repeatedly in random order 0.4 so that these faces became familiar. 0.3 0.2 3. During the test phase, 0.1 fMRIs were taken as the 0.0 participants viewed a series The most significant differences Novel faces Familiar faces of faces that mixed familiar in inhibited participants’ brain viewed viewed ones with novel ones. responses centered in the amygdala. CONCLUSION: Inhibited people show stronger amygdalar responses to unfamiliar faces than uninhibited people do. These findings suggest that some patterns of brain activity relating to temperament are preserved from infancy into early adulthood. SOURCE STUDY: Schwartz, Wright, Shin, Kagan, & Rauch, 2003 PThe Trait Approach: Defining Our DifferencesO 601  Traits and the Environment It seems plausible, then, that genes influence personality in a variety of ways—by deter- mining the reactivity of neurotransmitter systems, the threshold for activation in the amygdala, and more. But, as we have repeatedly noted, genetic influence will emerge only if certain environmental supports are in place. In addition, virtually any character- istic shaped by the genes is also likely to be shaped by environmental factors. What are the environmental factors relevant to the development of someone’s personality? Three sources of influence have been widely discussed: cultures, families, and differences among members within the same family. CULTURAL EFFECTS As we have seen, the evidence is mixed on whether the Big Five dimensions are as useful for describing personalities in Korea as they are in Kansas, as useful in Niger as they are in Newport. But no matter what we make of this point, we need to remember that the Big Five is simply a framework for describing how people differ; if the framework is in fact universal, this simply tells us that we can describe personalities in different cultures using the same (universal) measuring system, just as we can measure objects of different sizes using the same ruler. This still leaves open, however, what the personalities are in any given culture—that is, what we will learn when we use our measuring system. Scholars have long suggested that people in different cultures have different personalities—so that we can speak of a “German personality,” or a “typical Italian,” and so on. One might fear that these suggestions amount to little beyond stereotyping, and indeed, some scholars have argued that these perceptions may be entirely illusory (McCrae & Terracciano, 2006). Mounting evidence suggests, however, that there is a national character The idea that kernel of truth in some of these claims about national character. For example, one people in different cultures have dif- study has shown that there are differences from one country to the next in how consci- ferent personalities. entious people seem to be. These differences are manifest in such diverse measures as pedestrians’ walking speed, postal workers’ efficiency, accuracy of public clocks, and even longevity in each of these countries (Heine, Buchtel, & Norenzayan, 2008)! Where might these cultural differences in personality come from? One long- standing hypothesis is that the key lies in how a group of people sustains itself, whether through farming or hunting or trade (Barry, Child, & Bacon, 1959; Hofstede, 2001; Maccoby, 2000). More recent models, in contrast, take a more complex view, and sug- gest that cultural differences in personality—whether between nations or across regions within a single nation—arise via a combination of forces (Jokela, Elovainio, Kivimaki, & Keltikangas-Jarvinen, 2008; Rentfrow, Gosling, & Potter, 2008). These forces include historical migration patterns, social influence, and environmental factors that dynamically reinforce one another over time. To make this concrete, let’s consider immigrants who first make their way to a new geographical region (whether fleeing persecution or seeking prosperity). It seems unlikely that these trailblazers will be a ran- dom sample of the larger population. Instead, the mere fact that they decided to relo- cate suggests that they may be willing to take risks and more open to new experiences in comparison to others who were not willing to emigrate. This initial difference might then be magnified via social influence—perhaps because the especially extraverted or open individuals engaged in practices that shaped the thoughts, feelings, and behaviors of those around them. Arguments like these may help us understand why different regions within the United States often seem characterized by distinct personality types, with neuroticism especially common in some of the mid-Atlantic states and openness to new experience 602 chapter 15 PPERSONALITY O common in the Pacific Northwest. Indeed, one recent book (Florida, 2008) urges people to seek out regions that have personalities compat- ible with their own—providing yet another factor shaping regional or national personality: People may move to an area because they believe (or hope) certain traits are common there, and this selective migration can itself create or magnify regional differences (Figure 15.9). FAMILY EFFECTS It seems likely that another factor shaping personality is one’s family. If the family environment does influence personality, we would expect a resemblance between the personalities of adopted children and those of their adoptive siblings, because, after all, they grow up in the same Most Least environment. However, the data show no such resemblance. In one series of studies, in 15.9 Map of neuroticism in the United which researchers collected various personality measures for adopted children and for States According to these data, the eastern their adoptive siblings, the average correlation for these various measures was.04; that side of the country is a more “neurotic” place between the adopted children and their adoptive parents was.05 (Plomin & Daniels, to live than the western side (Rentfrow, 1987; also see Loehlin, 1992). Gosling, & Potter, 2008). A similar message emerges from a study that compared the personality traits of pairs of adult twins. Some of the twins had been reared within the same family; others had been reared apart and had been separated for an average of over 30 years. Among the twins reared together the personality scores for identical twins were, as usual, more highly correlated than the scores of fraternal twins, with correlations of.51 and.23, respectively. Thus, greater genetic resemblance (identical twins, remember, share all of their genes; fraternal twins share only half of their genes) led to greater personality resemblance. Amazingly, though, the twins who were reared apart and had been separated for many years showed nearly the same pattern of results as twins who grew up together. The correlations were.50 and.21 for identical and fraternal twins, respectively. (Moloney, Bouchard, & Segal, 1991). One might have expected the correlations to be considerably lower for the traits of the twins who had been raised apart, since they were reared in different family environ- ments. That the results were nearly the same whether the twins were raised together or apart speaks against granting much importance to the various environmental factors that make one family different from the next (Bouchard, 1984; Bouchard et al., 1990; Tellegen et al., 1988; also see Turkheimer & Waldron, 2000). Some authors have drawn strong conclusions from these data—namely, that the family plays little role in shaping personality (J. R. Harris, 1998). We would urge cau- tion, though, in making this sweeping claim. Most of the available evidence comes from families whose socioeconomic status was working class or above, and this range is rather limited. It does not include the environments provided by parents who are unemployed or those of parents who abuse or neglect their children. If the range had been broadened to include more obviously different environments, between-family environmental differences would surely have been demonstrated to be more important (Scarr, 1987, 1992). WITHIN-FAMILY EFFECTS If—within the range of environments studied—between-family environmental differ- ences are less important than one might expect, what environmental factors do mat- ter? According to Plomin and Daniels (1987), the key lies in how the environments vary for different children within the same family. To be sure, children within a family PThe Trait Approach: Defining Our DifferencesO 603  share many aspects of their objective environment. They have the same parents, they live in the same neighborhood, they have the same religion, and so on. But the environments of children within a family also differ in crucial ways. They have different friends, teach- ers, and peer groups, and these can play an important role in shap- ing how they behave. Moreover, various accidents and illnesses can befall one child but not another, with potentially large effects on their subsequent personalities. Another difference concerns the birth order of each child, since the family dynamic is different for the first-born than it is for later-born children (Figure 15.10). Some authors have suggested that birth order may have a powerful influ- (A) (B) ence on personality, with later-borns being more rebellious and more open to new experiences than first-borns (Sulloway, 1996). 15.10 Birth order Like other later-born Factors like these suggest that the family environment may matter in shaping per- individuals, (A) Voltaire was more rebel- sonality, but they indicate that we need to focus on within-family differences rather lious and more open to new experiences than between-family factors, like the fact that one family is strict and another lenient, than many first-borns. (B) Alec and Billy or the fact that some parents value education while others value financial achievement. Baldwin are a good example of the types of Indeed, within-family factors may be especially important since parents often do what personalities associated with first-born they can to encourage differences among their children; some authors have suggested and later-born siblings. that this is a useful strategy for diminishing sibling rivalry (Schachter, 1982). The gender of the child also plays a role. A brother and sister grow up in the same household, but are likely to be treated differently by their parents (not to mention other relatives, teachers, and friends). This, too, will provide a family influence shaping person- ality (although obviously these gender effects reach well beyond the family), but will once again produce within-family contrasts. In any case, this sort of differential treatment for men and women may—especially when combined with the biological differences between the sexes—help us understand why women score higher on the “agreeableness” dimension of the Big Five (Figure 15.11; Srivastava, John, Gosling, & Potter, 2003), and why women are less likely to be sensation-seekers (Zuckerman, 1994). In this context, though, we should also note that many of the popular conceptions about gender differ- ences in personality—which are surprisingly robust across cultures (Heine, 2008)—are probably overstated; in fact, women and men appear remarkably similar, on average, on many aspects of personality (Feingold, 1994; J. S. Hyde, 2005). 80 75 Percentage of maximum score 70 Females 65 60 Males 55 50 45 15.11 Gender differences regarding agreeableness At every age, women score higher on agreeableness 21 24 27 30 33 36 39 42 45 48 51 54 57 60 than men. Age (years) 604 chapter 15 PPERSONALITY O Contributions of the Trait Approach People differ from one another in a huge number of ways, and one of the major contri- butions of the trait approach lies in its systematic description of these differences and its success in reducing the apparently large number of these differences to manageable size. Moreover, the trait approach provides a set of continuous personality dimensions on which people can vary in almost infinite ways. This has certainly increased the precision of our personality descriptions. The trait approach offers us a rich notion of how personality and situations jointly shape behavior—leaving us with a more sophisticated theory and appreciably better predictions about how people of various personalities will behave in various settings. The emergence of the broad Big Five framework has also enabled researchers work- ing within very different traditions to use agreed-upon measures and to share the data they collect. As a result, progress on determining the genetic bases and brain corre- lates of personality differences has accelerated dramatically. Still, we must draw on other perspectives as well if we are to understand what a “personality” is, and how it comes to be. THE PSYCHODYNAMIC APPROACH: PROBING THE DEPTHS The comic theater of the classical and Renaissance ages presented personality types as stable and well-defined. Once a character entered, the audience knew what to expect of him. If the actor wore the mask of the cowardly soldier, he would brag and run away; if he wore the mask of the miserly old man, he would jealously guard his money. As we have seen, the trait approach has amended this view in important ways but has still left one crucial claim: We are who we seem to be, and our various traits and motivations are in plain view for all to see. Indeed, the trait approach often relies on self-report data—a reflection of the assumption that we can perceive ourselves with relative accuracy. According to the psychodynamic approach, however, we need to revise this under- standing both of personality and of self-knowledge—and shift to an understanding that parallels a more modern approach to drama, in which nothing is quite what it seems. In this approach, actors playing a character must pay attention to the subtext, the unspoken thoughts that go through the character’s head while she speaks her lines. And many actors are interested in a still deeper subtext, the thoughts and wishes of which the character is unaware. According to the psychodynamic approach, this deeper subtext is the wellspring of all human personality. Adherents of the psychodynamic approach do not deny that some people are more sociable than others, or that some are more impulsive or emotionally unstable. But they contend that it is superficial to explain such tendencies as either the expression of a personality trait or the product of situational factors. In their view, what people do and say—and even what they consciously think—is only the tip of the iceberg. As they see it, human acts and thoughts are just the outer expression of a whole host of motives and desires that are often derived from early childhood experiences, and that are for the most part unknown to the person himself. They believe that to understand a person is to understand these hidden psychological forces or dynamics. PThe Psychodynamic Approach: Probing the DepthsO 605