Temperament PDF

208 Chapter 9 / The Biological Approach Temperament If you were to spend a few minutes watching toddlers in a nursery school, you most likely would notice that even before they are a year old, some children clearly act differently than others. If you were to spend a week working in the nursery, yo...

208 Chapter 9 / The Biological Approach Temperament If you were to spend a few minutes watching toddlers in a nursery school, you most likely would notice that even before they are a year old, some children clearly act differently than others. If you were to spend a week working in the nursery, you could probably identify the active babies, the ones who cry frequently, and (hopefully) a few who are usually quiet and happy. Although it is possible these differences are the result of different treatment the children receive at home, a growing number of researchers are convinced these general behavioral styles are present at birth. Further, they argue that these general styles are relatively stable and influence the development of personality traits throughout a person’s life. But does this mean that some people are born to be sociable and others are born to be shy? Probably not. More likely we are born with broad dispositions toward certain types of behaviors. Psychologists refer to these general behavioral dispositions as temperaments. Temperaments are general patterns of behavior and mood that can be expressed in many different ways and that, depending on one’s experiences, develop into different personality traits. How these general dispositions develop into stable personality traits depends on a complex interplay of one’s genetic predispositions and the environment that a person grows up in. Temperament and Personality Although researchers agree that temperaments are general behavioral patterns often seen in newborns, they do not always agree on how to classify or how to measure the different kinds of temperaments they observe (Caspi, 1998; Clark, 2005; Evans & Rothbart, 2007; Kotelnikova, Olino, Mackrell, Jordan, & Hayden, 2013; Lo, Vroman, & Durbin, 2015; Shiner & DeYoung, 2013). Indeed, researchers often disagree on the number of basic temperaments. One popular model identifies three temperament dimensions—emotionality, activity, and sociability (Buss & Plomin, 1984, 1986). Emotionality refers to the intensity of emotional reactions. Children who cry frequently, who are easily frightened, and who often express anger are high in this temperament. As adults, these individuals are easily upset and may have a “quick temper.” Activity refers to a person’s general level of energy. Children high in this temperament move around a lot, prefer games that require running and jumping, and tend to fidget and squirm when forced to sit still for an extended period of time. Adults high on this dimension are always on the go and prefer high-energy activities like playing sports and dancing. Sociability relates to a general tendency to affiliate and interact with others. Sociable children seek out other children to play with. Adults high in this temperament have a lot of friends and enjoy social gatherings. Where do temperaments come from? Because we can identify temperamental differences in babies, it is not surprising that researchers find evidence that temperaments are largely inherited (Kandler, Riemann, & Angleitner, 2013; Mullineaux, Deater-Deckard, Petrill, Thompson, & DeThrone, 2009). In contrast to the approach taken by many physicians and psychologists a few decades ago, it is now widely agreed that not all babies are born alike. Parents with difficult-to-manage babies are often troubled by descriptions of the “typical” newborn who sleeps whenever put into a Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Temperament 209 crib, eats meals on a regular schedule, and responds to parental attention with calm, loving sounds. Fortunately, most popular baby books today assure parents that some babies are going to be more active and more emotional than others. Consistent with common observation, researchers also find gender differences in temperament (Else-Quest, Hyde, Goldsmith, & Van Hulle, 2006). Girls are more likely than boys to exhibit an effortful control temperament, which includes the ability to focus attention and exercise control over impulsive urges. On the other hand, boys are more likely than girls to be identified with a surgency temperament. This temperament pattern includes high levels of activity and sociability. These gender differences can be seen in children as young as 3 months of age. Can we look at temperament levels in preschool children and determine what kind of adult personalities they will have? To a certain degree, the answer is “Yes.” C ­ onsider the results of an ongoing longitudinal study conducted in Dunedin, New Zealand (Caspi, 2000; Caspi et al., 2003; Moffitt et al., 2007; Slutske, Moffitt, ­Poulton, & Caspi, 2012). Ninety-one percent of the children born in this town between April 1, 1972, and March 31, 1973, were tested for temperament at age 3. The researchers identified three temperament types in these toddlers. The well-adjusted children exhibited self-control and self-confidence and approached new people and situations with little difficulty. The undercontrolled children were impulsive and restless and easily distracted. The inhibited children were fearful, reluctant to get involved in social activities, and uneasy in the presence of strangers. The investigators then examined personality development and behavior at several points as the children moved through childhood and adolescence and into their young adult years. What did they find? As expected, the well-adjusted children became relatively healthy, well-adjusted adults. Also as expected, the undercontrolled and inhibited children’s lives had their difficulties. During the elementary school and adolescent years, undercontrolled children were more likely to have problems with fighting, lying, and disobeying at both school and home. As young adults, they were more likely to experience legal, employment, and relationship problems. By the time they reached 32, these individuals were twice as likely to have a problem with excessive gambling as the participants who had been classified as well-adjusted. Compared to the other two groups, inhibited children showed more signs of worrying and fussing when growing up, and as adults, they were less socially engaged and more likely to suffer from depression. Although temperament by no means is the sole determinant of adult personality and behavior, this study and others make the case that temperament plays an important role in personality development. The process through which general temperaments develop into personality traits is complex and influenced by a large number of factors (Caspi, 1998; Rothbart, 2007; Rothbart & Ahadi, 1994). Although the child’s general level of emotionality or activity points the development of personality in a certain direction, that development is also influenced by the child’s experiences as he or she grows up (Ganiban, Saudino, Ulbricht, Neiderhiser, & Reiss, 2008). For example, a highly emotional child has a better chance of becoming an aggressive adult than does a child low in this temperament. But parents who encourage problem-solving skills in place of expressing anger may turn a highly emotional child into a cooperative, nonaggressive adult. A child low in sociability is unlikely to become an outgoing, highly gregarious adult, but that child Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 210 Chapter 9 / The Biological Approach might develop excellent social skills, be a wonderful friend, and learn to lead others with a quiet, respectful style. Most temperament researchers accept that biologically based differences in temperament are directly related to differences in adult personality. But there is also a less direct connection. General behavioral dispositions also affect the development of personality traits because the child’s temperament influences the type of environment he or she lives in (Caspi, 1998; Johnson et al., 2016; Rothbart & Ahadi, 1994). That is, how other people react to us, and whether they will be a part of our environment at all, is partly determined by our temperament. For example, children high in sociability are likely to seek out situations with other people. Parents react differently to a baby who is constantly fussing and restless than to one who sleeps calmly. As a result, the restless baby experiences a different parent–child relationship than children with other temperaments. Temperament also generates expectations in other people that can affect the way they treat a child. Preschool teachers often use general activity levels to draw conclusions about a child’s personality (Graziano, Jensen-Campbell, & Sullivan-Logan, 1998). It is not hard to imagine that these different teacher expectations lead to treating each student a little differently. In short, adult personalities are determined by both inherited temperament and the environment. Moreover, temperament influences the environment, and the environment then influences the way temperament develops into stable personality traits. Within limits, two children born with identical temperaments can grow up to be two very different people. A child with a high activity level may become an aggressive, achieving, or athletic adult. But that child will probably not become lazy and indifferent. A child does not represent a blank slate on which parents may draw whatever personality they desire. But neither is a child’s personality set at birth, leaving the parents and society to settle for whatever they get. Inhibited and Uninhibited Children Several decades ago, two developmental psychologists reported the results of an investigation on personality trait stability (Kagan & Moss, 1962). They had measured traits when the participants were 2 or 3 years old and again when these same people were 20. Although most traits showed at least a little change over time, one appeared remarkably stable. The researchers found that children who were passive and cautious when faced with a new situation usually grew up to be adults who showed a similar pattern of shyness around strangers. Because environmental explanations of behavior were prevalent at the time, the researchers assumed this stable trait was the result of some type of “acquired fearfulness” shaped by the parents during childhood. Today those psychologists have a different interpretation. They argue that these different styles are the result of inherited dispositions (Kagan, 2003, 2013; Kagan & ­Snidman, 2004). Moreover, they find that approximately 10% of ­children fall into a category they refer to as “inhibited” (Kagan & Snidman, 1991a). Inhibited children are controlled and gentle. When they throw a ball or knock over a tower of blocks, they do so in a manner that is “monitored, restrained, almost soft.” Inhibited children are the ones who cling to their mothers or fathers when entering a new playroom or when meeting new children. They are slow to explore new toys or equipment and may go for several minutes without saying a word. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Temperament 211 Uninhibited children show the opposite pattern. Approximately 25% of the children in the researchers’ samples fall into this category (Kagan & Snidman, 1991a). These children jump right in to play with a new toy or to climb on a new piece of playground equipment. They usually start talking soon after they enter a new play area, even if they don’t know the other children playing there. On the surface, the difference between the two kinds of children appears to be their level of anxiety. But inhibited children are not simply more afraid of everything. Rather, they are vulnerable to a specific form of anxiety psychologists refer to as anxiety to novelty. These children are cautious about and at times fearful of new people and new situations. Inhibited toddlers often turn away from strangers and bury their face in mother’s or father’s leg. As adults, they may express their discomfort in a new situation by withdrawing socially and waiting for others to speak first. Inhibited and uninhibited children show a number of physical differences almost from the moment of birth (Fox, Henderson, Rubin, Calkins, & Schmidt, 2001; Moehler, Kagan, Brunner, Wiebel, Kaufmann, & Resch, 2006; Rosenberg & Kagan, 1989). They differ in terms of body build, susceptibility to allergies, and even eye color (inhibited children are more likely to have blue eyes). Inhibited children are more likely than uninhibited children to show signs of irritability, sleep disturbances, and chronic constipation during the first few months of life. Newborns later identified as inhibited children respond to unfamiliar stimuli with increased heart rate and pupil dilation (LaGasse, Gruber, & Lipsitt, 1989). Because these differences surface so early in life, researchers argue that they are likely inherited. Additional evidence for a biological foundation comes from research with older children and adults. In particular, neuroimaging studies find inhibited and uninhibited children’s brains react differently to events and images (Bar-Haim et al., 2009). In one investigation, 10- to 12-year-old boys and girls classified as inhibited reacted to noises with different brain stem responses than did uninhibited children (Woodward et al., 2001). Other investigators find inhibited children have an abnormally high amygdala response (Perez-Edgar et al., 2007; Schwartz, Wright, Shin, Kagan, & Rauch, 2003) or increased striatum activity (Helfinstein, Fox, & Pine, 2012) when presented with highly novel or uncertain stimuli. Of course, how inhibited children express their anxiety changes as they mature. Nonetheless, researchers find evidence for a fear of the unfamiliar throughout childhood and into adulthood (Fox, Snidman, Haas, Degnan, & Kagan, 2015; Gest, 1997; Hardway, Kagan, Snidman, & Pincus, 2013; Kagan & Snidman, 2004; Moehler et al., 2008). Trained judges in one study looked at motor activity—arm and leg movements, tongue protrusions, and crying—in 4-month-old infants to place the children into inhibited and uninhibited categories (Kagan, 1989; Kagan & Snidman, 1991a, 1991b). The psychologists observed the children again at ages 9, 14, and 21 months to see how the toddlers would react to unfamiliar events, such as seeing a puppet speaking in an angry tone or being shown a large metal robot they could play with. Forty percent of the infants classified as inhibited showed signs of fear, such as crying or hiding, at 14 and 21 months, but none of the uninhibited children did. These temperamental differences can also be seen when the children reach school age (Rimm-Kaufman & Kagan, 2005). One team of investigators measured children’s fear of unfamiliar situations at 21 months of age (Reznick et al., 1986). When the Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 212 Chapter 9 / The Biological Approach children reached age 5 1/2, they were brought back into the laboratory and examined in a number of situations. Experimenters coded how much the children played with unfamiliar children in the laboratory playroom, how spontaneously they allowed themselves to fall onto a mattress when playing a falling game, and how much risk they took in a ball-tossing game. As shown in Table 9.1, the children who had shown an inhibited behavior pattern as infants exhibited similar behaviors at age 5 1/2. In other words, the toddler who clung to mother or father in a new situation showed a similar style of behavior when examined 4 years later. It is easy to see how this fear of the unfamiliar can set inhibited children on a path toward shyness. Indeed, investigators find that inhibited children are significantly more likely than uninhibited children to become shy teenagers (Schwartz, Snidman, & Kagan, 1999). However, researchers also find that inhibited children are also at risk for developing social anxiety disorder (Chronis-Tuscano et al., 2009; Perez-­Edgar et al., 2010). One team of reviewers estimated that inhibited children were seven times more likely to suffer from social anxiety disorder in adolescence than children not identified as inhibited (Clauss & Blackford, 2012). But what about after that? Do inhibited children become inhibited adults? To answer this question, one study measured inhibition in a group of children between the ages of 8 and 12 (Gest, 1997). These same participants were tested again nearly 10 years later, just as they were entering early adulthood. The investigator found an impressively high correlation of .57 between the two measures, indicating that quiet, apprehensive children retain many of these characteristics when they become adults. Another study found that being an inhibited child was a risk factor for adult anxiety disorders, especially social phobia (Biederman et al., 2001). Table 9.1 Correlations Between Inhibition Measures at 21 Months and Behaviors at Age 5 1/2 Years Behavior at Age 5 1/2 Years Correlation with Inhibition Score at 21 Months Play with unfamiliar children .43 Laboratory activity level .38 Look at experimenter .22 Play with new toys .19 Spontaneous falling .40 Ball-toss riskiness .35 Social interaction in school .34 Mother’s rating of shyness .36 Note: The higher the score, the better the inhibition score predicts the behavior. Source: Reznick J. S., et al. (1986). Inhibited and uninhibited children: A follow-up study, Child Development, 57, 660–680. Reprinted by permission of the Society for Research in Child Development, Inc. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Evolutionary Personality Psychology 213 Jerry Burger/Santa Clara University Do these results mean inhibited children are sentenced to become shy adults? Fortunately, the answer is “No.” Parents of inhibited children can do their offspring a favor by becoming sensitive to the child’s discomfort in unfamiliar settings and by teaching the child how to deal with new situations and new acquaintances. Research indicates that many business leaders, community workers, and entertainers have learned to overcome their shyness and lead very social lives. It also is an open question as to whether the connection between inhibited children and later social problems applies to all cultures. One study with Chinese children found that toddlers identified as inhibited at age 2 actually had Some children appear to inherit a tendency better social relationships at age 7 to respond to unfamiliar situations with than the average child (Chen, Chen, increased arousal. When entering a new Li, & Wang, 2009). situation with new people, many of these Finally, although most of the children display what we typically call “shy” behavior. research in this area has been focused on inhibited children, researchers also find that uninhibited children are susceptible to their own set of potential problems. In particular, uninhibited children are more likely than most to exhibit disruptive behavior disorders, including aggressiveness, and to have attention problems (Biederman et al., 2001; Schwartz, Snidman, & Kagan, 1996). But once again, parents and others have a hand in determining how this inherited temperament expresses itself when these uninhibited children become adolescents and adults. Evolutionary Personality Psychology T hink for a moment about a recent experience you have had with anxiety. What was happening the last time you felt nervous, worrisome, or anxious? Although direct threats to our well-being—such as an earthquake or physical assault—are certainly sources of anxiety, these kinds of events are relatively rare and probably did not make your list. Instead, if you are like most people, you probably thought of something like talking in front of a group, embarrassing yourself at a party, or having a fight with a friend. In other words, it’s likely you recalled a situation that potentially included negative evaluation by other people and possibly even rejection. Or you may have thought of a situation that only suggested that negative social evaluation might be coming, such as forgetting to turn in an assignment or discovering that you forgot to use deodorant one morning. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 214 Chapter 9 / The Biological Approach What this simple exercise illustrates is that negative evaluation by other people, either directly or potentially, is a common source of anxiety. But why might this be the case? Is this a learned behavior? Have we been conditioned to fear situations in which other people dislike us? That’s certainly possible. Could there be a psychoanalytic basis for this anxiety? At some deep level, are we reminded of a traumatic separation from our childhood? Perhaps. But another explanation suggests that the roots of anxiety go back much further than this. According to this approach, we react to negative social evaluation in the same way our ancestors did. Moreover, this inherited tendency to become nervous and upset in certain situations allowed our species to survive. This different approach is known as evolutionary personality theory (Buss, 2008, 2009). Proponents of this theory use the process of natural selection, borrowed from the theory of evolution, to explain universal human characteristics such as anxiety. These psychologists argue that many characteristics we call “human nature” make sense if we understand the evolutionary function they serve. We’ll return to the example of anxiety later to illustrate this point. First, we need to examine some of the assumptions underlying the theory. Natural Selection and Psychological Mechanisms Evolutionary personality psychology is based on the theory of evolution, as developed in the field of biology for more than a century. According to evolution theory, physical features evolve because they help the species survive the challenges of the environment and reproduce new members of the species. The key to this process is natural selection. That is, some members of a species possess inherited characteristics that help them meet and survive the threats from the natural environment, such as severe climate, predators, and food shortages. These survivors are more likely than those less able to deal with the environment to reproduce and pass their inherited characteristics on to their offspring. The net result over many generations is the evolution of species-specific features. Through the process of natural selection, species develop features that help them survive and prosper, and those failing to develop these features die out. In many cases, physical features evolve because they provide solutions to a serious threat to a species’ survival. For example, in humans, the problem of disease was limited by the evolution of an immune system, and the potential problem of bleeding to death when cut or wounded was solved with the evolution of blood clotting (Buss, 1991). This is not to say that these features were created because they were needed. Rather, the theory of evolution maintains that because of these changes our species was better prepared to survive. According to evolutionary personality theory, just as natural selection has led to the evolution of certain physical characteristics in humans, the process is also responsible for what are called psychological mechanisms. These psychological mechanisms are characteristically human functions that allow us to deal effectively with common human problems or needs. Through the process of natural selection, mechanisms that increased the chances of human survival and reproduction have been retained, and those that failed to meet the challenges to survival have not. Psychologists have identified a large number of these mechanisms. For example, most humans have an innate fear of strangers. Evolutionary personality psychologists Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Evolutionary Personality Psychology 215 argue that this fear evolved to meet the problem of attack by those not belonging to our group or tribe (Buss, 1991). Similarly, anger might have assisted our ancestors in such survival behaviors as asserting authority and overcoming enemies (McGuire & Troisi, 1990). Thus it makes sense that anger is a common human characteristic. Some psychologists argue that humans have an innate need to belong to groups and form attachments (Baumeister & Leary, 1995). It is not difficult to imagine how a species that worked together would survive better than a species that did not. Similarly, some researchers maintain that the human characteristic of compassion helps the species survive because it leads to protection of individuals in need (Goetz, Keltner, & Simon-Thomas, 2010). But whereas the survival function of some human characteristics may be easy to explain, the advantages of other psychological mechanisms might not be so obvious. We turn next to one such mechanism. Anxiety and Social Exclusion Evolutionary personality theorists often point to emotions as shared human characteristics that serve evolutionary functions (Al-Shawaf, Conroy-Beam, Asao, & Buss, 2016; Lench, Bench, Barbor, & Moore, 2015). These psychologists propose that sadness, anger, disgust, and other emotions promoted behaviors that helped our ancestors survive. Curiously, this list of advantageous emotions also includes anxiety. At first glance, it is difficult to see the benefits of anxiety. Certainly, it is an unpleasant emotional state, something a normally functioning person would prefer to avoid. Moreover, anxiety is almost always problematic. It interferes with our ability to learn new tasks, remember information, perform sexually, and so on. How can something as disruptive as anxiety help the species? We can answer this question by looking at what causes anxiety. Some psychologists have argued that one of the primary causes of anxiety is social exclusion (Baumeister & Tice, 1990; Bulley, Miloyan, Brilot, Gullo, & Suddendorf, 2016). These investigators propose that all humans have a strong need to belong to groups and to be in relationships. Consequently, when we experience exclusion or rejection from social groups, we suffer great distress. This distress is not just limited to those relatively rare instances when we are literally rejected from a group or tossed out of a relationship. Rather, any information that suggests we might be excluded socially or we are no longer attractive to other people is threatening to our need to belong. Thinking about anxiety as fear of social rejection helps us understand why people feel anxious when they have to give a speech in front of an audience or when they discover that first gray hair. The speaker is afraid the audience members will evaluate him or her negatively, a form of social rejection. The 30-ish adult discovering a gray hair worries about his or her attractiveness to others. Although outright social rejection is not common, fear of what others will think of us may be an everyday experience. This social exclusion explanation of anxiety fits nicely with evolutionary personality theory. Primitive people who lived together in small groups were more likely to survive and reproduce than those living alone. An isolated person would be more susceptible to injury, illness, lack of shelter, and limited resources and would be less able to mate and raise offspring than individuals living in groups or tribes. Consequently, anything that motivates people to avoid behaviors that might lead to their exclusion from the group would help the species survive. Anxiety serves this purpose. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.