The Biological Approach PDF

3 9 The Biological Approach Theory, Application, and Assessment Hans Eysenck’s Theory of Personality Temperament Evolutionary Personality Psychology Application: Children’s Temperaments and School Assessment: Brain Electrical Activity and Cerebral Asymmetry Strengths and Criticisms of the Biological...

3 9 The Biological Approach Theory, Application, and Assessment Hans Eysenck’s Theory of Personality Temperament Evolutionary Personality Psychology Application: Children’s Temperaments and School Assessment: Brain Electrical Activity and Cerebral Asymmetry Strengths and Criticisms of the Biological Approach DNY59/E+/Getty Images Summary 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. 200 Chapter 9 / The Biological Approach H ave you ever been told that you act like one of your parents? Perhaps a relative has said, “You’re your mother’s son (daughter), all right.” My brother’s quick temper has often been described as “inherited from his father.” I know one couple who were more interested in learning about the family of their daughter’s fiancé than about the fiancé. They told me that meeting the new in-laws would help them see what their future grandchildren would be like. As these examples suggest, the notion that children inherit characteristics from their parents is widely held in this society. Not only do people accept that parents pass physical characteristics, such as eye color or height, through their genes, but we often expect children’s personalities to resemble their parents’. Although conventional wisdom has for years acknowledged the role of biology in the development of personality, the same cannot be said of many psychologists. Several decades ago, many academic psychologists looked at all healthy newborns as blank slates, perhaps limited by differences in intelligence or physical skills but otherwise equally likely to develop into any kind of adult personality. Different adult personalities were attributed to differences in experiences, particularly in the way parents raised their children during the child’s early years. However, this view has changed. No reputable psychologist would argue that people are born with their adult personalities intact, but today few psychologists would deny that personality is at least partly the result of inherited biological differences. This acceptance of a genetic influence on personality has coincided with a growing recognition that personality cannot be separated from other biological factors. Research tells us that not all people have identical physiological functioning. We can identify differences between people in terms of brainwave activity, hormone levels, heart-rate responsiveness, and other physiological features. More important for personality psychologists, researchers find these biological differences often translate into differences in behavior. We’ll review an example of this later in this chapter when we look at individual differences in brainwave patterns. We also have seen in recent years a growing recognition that human personality, like other human features, is the product of many generations of evolutionary development. Just as biologists find it useful to ask about the evolutionary function of the physical characteristics of a species, some psychologists have found this same question useful in understanding certain features of personality. This growing acceptance of a biological influence on personality is partly a reflection of behaviorism’s declining influence on the thinking of academic psychologists. As described in Chapter 13, early behaviorists tended to ignore individual differences among newborns, and a few even claimed that with enough control over the child’s experiences they could shape a child into whatever personality they wanted. Probably no behaviorist would argue such an extreme position today. The movement away from the “blank slate” position has also been stimulated by research demonstrating rather clearly that at least some of our personality is inherited from our parents. This research is reviewed in Chapter 10. In this chapter, we’ll look at three ways psychologists have used biological concepts to explain personality. First, we examine Hans Eysenck’s description of personality, which has been an influential model in personality research for several decades. From the beginning, Eysenck maintained that the individual differences in personality 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. Hans Eysenck’s Theory of Personality 201 he described are based on physiological differences. Second, we look at individual differences in general dispositions, called temperaments. A strong case can be made that temperaments are based on biological differences. Third, we examine an area of personality research called evolutionary personality psychology. Psychologists using this approach borrow the concept of natural selection from biology to explain a large number of human behaviors. What each of these three theoretical perspectives makes clear is that a complete understanding of human personality requires us to go beyond some of the early boundaries of the discipline. It is no longer useful to think of our personality as somehow separate from our physiological makeup. Hans Eysenck’s Theory of Personality M any years ago, when the conventional wisdom in psychology traced an individual’s personality to his or her experiences, a respected psychologist argued that personality was, in fact, determined more by biological makeup than by any actions or mistakes made by one’s parents. Although Hans Eysenck’s (pronounced Eye-Zinc) theory of personality has always been accorded respect within the field, his initial claims about a large biological determinant of personality were met by many with a mix of skepticism and tolerance. But today, Eysenck’s emphasis on biological aspects of individual differences is increasingly compatible with the recognition of biology’s role in personality. The Structure of Personality Like Raymond Cattell and other psychologists described in Chapter 7, Eysenck was concerned with discovering the underlying structure of personality. Also like these trait researchers, Eysenck employed factor analysis to identify the basic number of what he called types, or supertraits. However, unlike most of the trait researchers, Eysenck’s conclusion after years of research was that all traits can be subsumed within three basic personality dimensions. He called these three dimensions extraversion– introversion, neuroticism, and psychoticism. Eysenck’s research strategy began by dividing the elements of personality into various units that can be arranged hierarchically (Figure 9.1). The basic structure in this scheme is the specific response level, which consists of specific behaviors. For example, if we watch a man spend the afternoon talking and laughing with friends, we would be observing a specific response. If this man spends many afternoons each week having a good time with friends, we have evidence for the second level in Eysenck’s model, a habitual response. But it is unlikely that this man limits himself to socializing just in the afternoon and just with these friends. Suppose this man also devotes a large part of his weekends and quite a few evenings to his social life. If you watch long enough, you might find that he lives for social gatherings, group discussions, parties, and so on. You might conclude, in Eysenck’s terms, that this person exhibits the trait of sociability. Finally, Eysenck argued that traits such as sociability are part of a still larger dimension of personality. That is, people who are sociable also tend to be impulsive, active, lively, and excitable. All these traits combine to form the supertrait that Eysenck called extraversion. 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. Chapter 9 / The Biological Approach Supertrait Level: Extraversion Specific Response Level: Activity Liveliness Excitability HRn HR4 HR3 HR2 HR1 Impulsiveness SR1 SR2 SR3 SR4 Habitual Response Level: Sociability SRn–1 SRn Trait Level: HRn–1 202 Figure 9.1 Eysenck’s Hierarchical Model of Personality How many of these supertraits are there? Originally, Eysenck’s factor analytic research yielded evidence for two basic dimensions that could subsume all other traits: extraversion–introversion and neuroticism. Because the dimensions are independent of one another, people who score on the extraversion end of the first dimension can score either high or low on the second dimension. Further, as shown in Figure 9.2, someone who scores high on extraversion and low on neuroticism possesses traits ­different from a person who scores high on both extraversion and neuroticism. If you are the prototypic extravert, you are “outgoing, impulsive, and uninhibited, having many social contacts and frequently taking part in group activities. The typical extravert is sociable, likes parties, has many friends, needs to have people to talk to, and does not like reading or studying by himself” (Eysenck & Eysenck, 1968, p. 6). An introvert is “a quiet, retiring sort of person, introspective, fond of books rather than people; he is reserved and distant except to intimate friends” (p. 6). Of course, most people fall somewhere between these two extremes, but each of us is perhaps a little more one than the other. The second major dimension in Eysenck’s model is neuroticism. High scores on this dimension indicate a tendency to respond emotionally. We sometimes refer to people high in neuroticism as unstable or highly emotional. They often have strong emotional reactions to minor frustrations and take longer to recover from these. They are more easily upset, angered, and depressed than most of us. Those falling on the other end of the neuroticism dimension are less likely to fly off the handle and less prone to large swings in emotion. 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. Hans Eysenck’s Theory of Personality Figure 9.2 Traits Associated with Eysenck’s Two Major Personality Dimensions Source: Eysenck, H. J., and Eysenck, B. G. (1968). Manual for the Eysenck Personality Inventory. San Diego: EDITS. Reprinted by permission of Educational and Industrial Testing Service. 203 Unstable (Neurotic) Moody Anxious Rigid Sober Pessimistic Reserved Unsociable Quiet Introverted Passive Careful Thoughtful Peaceful Controlled Reliable Even-tempered Calm Touchy Restless Aggressive Excitable Changeable Impulsive Optimistic Active Extraverted Sociable Outgoing Talkative Responsive Easygoing Lively Carefree Leadership Stable You no doubt will notice that these first two dimensions are similar to—and indeed, share the names of—two of the dimensions from the Big Five model of personality (Chapter 7). Obviously, this is not a coincidence. Although Eysenck used the labels extraversion and neuroticism first, later factor analytic researchers found they were apt descriptions of two dimensions that surfaced in their work. Research findings later led Eysenck to add a third supertrait: psychoticism. People who score high on this dimension are described as “egocentric, aggressive, impersonal, cold, lacking in empathy, impulsive, lacking in concern for others, and generally unconcerned about the rights and welfare of other people” (Eysenck, 1982, p. 11). Needless to say, people scoring particularly high on this dimension are good candidates for some type of judicial correction or psychotherapy. “Heritability is not a fixed number. Once you realize what’s inherited, there’s a lot you can do about it.” Hans Eysenck A Biological Basis for Personality Eysenck (1990) provided three arguments when making the case that individual differences in personality are based in biology. First, he noted the consistency of extraversion–introversion over time. For example, one study found that participants’ scores on measures of extraversion–introversion remained fairly consistent over a span of 45 years (Conley, 1984, 1985). Of course, this finding alone does not establish that extraversion–introversion is determined through biology. It is possible that people remain in similar environments throughout their lives. Or the finding may simply mean that after this part of personality is established, it is difficult to change. 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. 204 Chapter 9 / The Biological Approach Second, Eysenck pointed to the results of cross-cultural research. Investigators often find the same three dimensions of personality—extraversion–introversion, neuroticism, and psychoticism—in studies conducted in many different countries with people from very different cultures (Barrett & Eysenck, 1984; Bowden, Saklofske, van de Vijver, Sudarshan, & Eysenck, 2016; Lynn & Martin, 1995). Moreover, the same three superfactors appear in studies using different data-gathering methods (Eysenck & Long, 1986). Eysenck maintained that this level of cross-­ cultural consistency would be unlikely unless biological factors were largely responsible for personality. Third, Eysenck noted the results of several studies indicating that genetics plays an important role in determining a person’s placement on each of the three ­personality dimensions. As presented in detail in Chapter 10, that research strongly suggests that how introverted or extraverted you are is a result of your genetic makeup. After examining the evidence from all of these sources, and no doubt adding a bit of his own intuition, Eysenck (1982) asserted that about two-thirds of the variance in personality development can be traced to biological factors. Although the exact figure may not be this high, data from a continuing stream of studies suggest that extraverts and introverts differ on a number of biological measures (Cox-Fuenzalida, Gilliland, & Swickert, 2001; Doucet & Stelmack, 2000; Stelmack & Pivik, 1996). This is not to say that environmental factors do not play a role. But, as the evidence reviewed in the next chapter makes clear, biology probably sets limits on how much we can change an introverted friend into a highly sociable individual or the likelihood of shaping an impulsive, outgoing child into a calm, easygoing adult. Physiological Differences: Stimulation Sensitivity and Behavioral ­Activation/Inhibition Systems Eysenck argued that extraverts and introverts differ not only in terms of behavior but also in their physiological makeup. He originally maintained that extraverts and introverts have different levels of cerebral cortex arousal when in a nonstimulating, resting state (Eysenck, 1967). Although it may sound backward at first, he proposed that extraverts generally have a lower level of cortical arousal than do introverts. Extraverts seek out highly arousing social behavior because their cortical arousal is well below their desired level when doing nothing. In a sense, highly extraverted people are simply trying to avoid unpleasant boredom; their problem is feeding their need for stimulation. Introverts have the opposite problem. They typically operate at a cortical arousal level that is near or perhaps even above the optimal amount. These people select solitude and nonstimulating environments to keep their already high arousal level from becoming too aversive. For these reasons, extraverts enjoy a noisy party that introverts can’t wait to leave. Sensitivity to Stimulation Unfortunately, a great deal of research has failed to uncover the different levels of base-rate cortical arousal proposed by Eysenck. Introverts and extraverts do differ in 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. Hans Eysenck’s Theory of Personality 205 how certain parts of their brains respond to emotional stimuli (Canli, 2004). However, they show no differences in brain-wave activity when at rest or when asleep (Stelmack, 1990). But this does not mean that Eysenck’s original theorizing was entirely off base. Rather, there is ample evidence that introverts are more sensitive to stimulation than extraverts (Bullock & Gilliland, 1993; Stelmack, 1990; Swickert & Gilliland, 1998). That is, introverts are more quickly and strongly aroused when exposed to external stimulation. Introverts are more likely to become aroused when they encounter loud music or the stimulation found in an active social encounter. Introverts are even more responsive than extraverts when exposed to chemical stimulants, such as caffeine or nicotine. As a result of these research findings, many researchers now describe extraverts and introverts in terms of their different sensitivity to stimulation rather than differences in cortical activity. However, the effect is essentially the same. Because of physiological differences, introverts are more quickly overwhelmed by the stimulation of a crowded social gathering, whereas extraverts are likely to find the same gathering rather pleasant. Extraverts are easily bored by slow-moving movie plots and soft music, but introverts often find these subtle sources of stimulation engaging. Sensitivity to Reinforcement: The Behavioral Approach System and the Behavioral Inhibition System Other researchers tie differences in extraversion and neuroticism to biologically based differences in sensitivity to reinforcement (Smillie, 2013). According to reinforcement sensitivity theory (Gray, 1982, 1987; Gray & McNaughton, 2000), each human brain has a behavioral approach system (BAS) and a behavioral inhibition system (BIS). The exact regions of the brain and the specific processes involved in each of these hypothetical systems remain to be determined. Nonetheless, like other personality concepts, individuals are said to differ in the strength of these two systems, and these individual differences are relatively stable over time. People with a highly active BAS are intensely motivated to seek out and achieve pleasurable goals. Compared to people low on this dimension, they get more pleasure out of rewards and more enjoyment out of simply anticipating that rewards are coming. Individuals with an active BAS also experience more anger and frustration when they fall short of reaching anticipated sources of pleasure. People with a highly active BIS tend to be more apprehensive than others. They approach new situations warily, are on a constant lookout for signs of danger, and are quick to retreat from a situation that they sense might lead to problems. Not surprisingly, they also are more likely to experience anxiety than people low on this dimension. Just how these two hypothetical systems are related to Eysenck’s theory remains a matter of debate (Smillie, Pickering, & Jackson, 2006). But most researchers see a connection between the BAS and extraversion and a connection between the BIS and neuroticism. That is, people with a highly active BAS are similar to those scoring high in extraversion, and those with a highly active BIS are similar to people scoring high in neuroticism. Consistent with this analysis, scales designed to measure BAS and BIS correlate with scales measuring extraversion and neuroticism, respectively. However, the correlation is far from perfect (Jackson, 2009; Li et al., 2015). Thus, although the concepts are related, they probably are not exactly the same. 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. Reproduced by permission from The H. J. Eysenck Memorial Fund/University of London Hans J. Eysenck 1916–1997 If heredity plays a large role in determining personality, we might say that Hans Eysenck was born to be the center of attention in whatever field he entered. Eysenck was born in Germany into a family of celebrities. His father, Eduard Eysenck, was an accomplished actor and singer, something of a matinee idol in Europe. His mother, whose stage name was Helga Molander, was a silent film star. They planned a glamorous career in the entertainment field for Hans, who at age 8 had a small role in a motion picture. However, like many H o l l y w o o d m a r r i a g e s t o d a y, Eysenck’s parents divorced when he was young (only to later marry other show business people). Most of Eysenck’s early years were spent with his grandmother in Berlin. Upon graduating from public school in Germany, the rebellious Eysenck decided not only to pursue a career in physics and astronomy, much to his family’s displeasure, but also to do so abroad. After a year in France, he moved to England, where he eventually completed his PhD at the University of London. Like so many others at the time, Eysenck left Germany in 1934 in part to escape the rise of the Nazis. “Faced with the choice of having to join the Nazi storm troops if I wanted to go to a university,” he wrote, “I knew that there was no future for me in my unhappy homeland” (Eysenck, 1982, p. 289). Because he was a German citizen, Eysenck was prohibited from joining the British military and spent World War II working in an emergency hospital. Following the war, he returned to the University of London, where his long career produced 79 books and more than 1,000 journal articles (Farley, 2000). Although Eysenck never pursued the career in show business his parents desired, he did not avoid the public’s eye. In fact, he sought out and dove right into some of the biggest controversies in psychology. He was, in one biographer’s words, “a magnet for attention” (Corr, 2016). In 1952 Eysenck published a paper challenging the effectiveness of psychotherapy. He was especially critical of psychoanalysis, pointing out that empirical evidence at the time showed psychoanalysis to be no better than receiving no treatment at all. More controversy occurred when he stated that individual differences in intelligence are largely inherited. As a result, Eysenck was sometimes unfairly associated with those who proposed inherent racial differences in intelligence. In 1980, Eysenck published a book arguing that the case for cigarettes as a cause of health problems was not as strong as many people claimed. Critics were particularly harsh when they discovered that some of this work had been sponsored by American tobacco companies. This lifelong combative style caused one biographer to call Eysenck the “controversialist in the intellectual world” (Gibson, 1981, p. 253). Eysenck would no doubt have enjoyed this title. “From the days of opposition to Nazism in my early youth, through my stand against Freudianism and projective techniques, to my advocacy of behavior therapy and genetic studies, to more recent issues, I have usually been against the establishment and in favor of the rebels,” he wrote. “[But] I prefer to think that on these issues the majority were wrong, and I was right” (1982, p. 298). 206 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. Hans Eysenck’s Theory of Personality 207 Photo courtesy of Marlene Somsak Nonetheless, when looked at within this framework, we can think of extraverts as people who are more aware of and more attracted to situations that promise rewards than are introverts. When extraverts encounter an opportunity to have a good time, they are motivated to approach the object of their desire. As a result, extraverts are more impulsive than introverts and are more likely to find themselves in the middle of a party or riding on a roller coaster. One implication of this description is that extraverts aren’t necessarily attracted to all social situations, but only to those that are likely to be enjoyable (Lucas, Diener, Grob, Suh, & Shao, 2000). Consistent with this hypothesis, one team of researchers found that extraverts actually preferred nonsocial situations, such as going for a walk alone, more than introverts did if they thought the experience would be pleasant (Lucas & Diener, 2001). How do you spend your spare time? If you’re an extravert, it probably never occurs to you to take a long walk by yourself. If you’re an introvert, you may rely on a long walk to reduce your arousal level after an intense and active day. 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.