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Behavior Genetic Approaches in Behavioral Medicine
217
Book reviews
conceptual analysis of fear antecedents (Sartory), as well as a survey of the fascinating research on the measurement of stimulus prepotency and fear conditioning through startle modulation and other psychophysiological techniques (Hamm & Vaitl, Ghman). The contributions in the last section come back to major theoretical issues involved, such as the relation of arousal and affective valence to the startle reflex modulation (Lang, Bradley, & Cuthbert), the different responsivity of the startle reflex and skeletal reflexes to affective valence (Requin & Bonnet), emotion processing in anhedonia, as studied by startle modulation, and the value of the startle probe to investigate emotion and emotional disorders (Bradley & Vrana). The chapters vary in level, interest, and appeal. Together, they offer an excellent overview of this important approach to the study of emotion, and the variety of domains in which it has proven to be fruitful. The book provides a concise way to get solidly informed both about theory, research methods, and results that cannot easily be found together in another way.
University
Nice H. Frijda of Amsterdum The Netherlunds
Behavior Genetic Approaches in Behavioral Medicine. J.R. Turner, L.R. Cardon, and J.K. Hewitt (Eds.), Plenum Press, New York, 1995, pp. xvi + 273, $54.00. ISBN o-306-44969-2
This edited volume is an excellent review of the area. The chapters are well-written and are better integrated than is usually the case for edited books. Most of the material is presented in a manner which is accessible by advanced undergraduate and graduate students, yet contains enough detail and nuance for a professional audience. The book slices up the area in two different ways: chapters focusing on the use of behavior genetic approaches to understand specific clinical problems such as alcohol use, cigarette smoking, high blood pressure, cardiovascular reactivity to stress, obesity and eating disorders, as well as several chapters devoted to approaches for dealing with issues which cut across problems such as ethnic and gender differences, genetic influences on environmental measures, etc. Although all of the chapters should be useful to those interested in behavioral medicine and provide a distinctive slant on their area, some (e.g. the chapters on cardiovascular reactivity to stress) will probably be a bit more interesting to the general health psychology audience as the material is less likely to be reviewed elsewhere. Consistent with the raison d’etre of behavioral medicine, i.e. that health and illness need to be viewed from a perspective which includes physiological, behavioral, and social influences, the book emphasizes the use of behavior genetic techniques to study both genetic and environmental influences on health-related behavior. One thought which came to mind as I read the book was a comment by
218
Book reviews
Sandra Starr in her Presidential address to the Behavior Genetic Association a few years ago that the field of behavior genetics had in a sense ‘lost the battle but won the war’. That is, I believe that she was somewhat concerned about the future of the society, but only because the acceptance of behavior genetic techniques to elucidate both genetic and environmental influences on a wide range of behaviors had become so great as to induce investigators to attend non-behavioral genetic conferences and to submit their work to journals outside the behavior genetic field, e.g. in journals focusing on specific problems in the addictions, psychopathology, and health psychology (I confess to being one of the latter). While the authors’ attempts may not convince some die-hard environmentalists of the value of behavior genetic techniques, the authors try hard to make the point that behavior genetic analysis does not stop with the calculation of a heritability coefficient. In fact, it only really begins at that point. For example, with the exception of the determination of the actual mechanisms of the effect, the quantitative genetics of body weight might seem to be a fairly simple question. However, the chapters on the genetics of childhood body mass index and lifetime obesity focus on more complex issues such as the factors influencing the distribution of fat in the body and the stability of weight across the life span. Heritable influences on birth weight are considerable, but not particularly relevant to body mass index several years later. Genetic influences on early childhood body mass continue to affect weight for several years, with the periodic addition of new genetic influences. As discussed in the section on adiposity rebound, some of these may have greater relevance for the problem of adult obesity than others. The idea that behavior genetic analysis must deal with ‘moving targets’, that is, characteristics or behaviors which are constantly changing in a complex social and cultural matrix, is a recurring theme in the book. This underscores the fact that a heritability coefficient is really just an estimate (albeit an important estimate) of the proportion of variance due to heritable influences in a group at a particular point in time, and not an immutable characteristic. The chapters on cigarette smoking provide perhaps the best argument for the use of behavior genetic designs to understand environmental as well as genetic influences on health-related behavior. For example, the results of twin studies of the heritability of smoking are discussed by Heath and Madden in terms of the era in which they were conducted. The results were re-analyzed using comparable techniques, making it difficult to attribute different findings to differences in methodology. All of the studies produced evidence of significant genetic influence on both the acquisition and maintenance of cigarette smoking behavior. More interestingly, the authors also observed a significant influence of the family environment on cigarette smoking in more recent samples. This may reflect the fact that there are now social pressures against as well as for smoking. The presence of an influence of the family environment on smoking is striking given the general lack of such effects on personality (for which the bulk of the variance is explained by additive genetic and individual-specific environmental effects). In the following chapter, Rowe and Linver present a biosocial model for cigarette smoking which starts with a somewhat sociobiological interpretation of the most
219
Book reviewIs
common environmental explanation for the initiation of smoking, i.e. peer pressure. That is, smoking is compared to the display of a ‘self-handicapping’ characteristic. Although this may have certain adverse effects, their negative impact is overshadowed by the independence and ‘fitness’ this behavior supposedly displays to others. The sociobiology is not overplayed, however. A certain amount of evidence consistent with this viewpoint is cited (e.g. findings that blood testosterone level moderates social influences on smoking) and, more importantly, this provides an interesting basis to discuss environmental influences on smoking acquisition. The relatively low parent-offspring similarity in smoking is noted as support for the view that adolescents do not usually begin to smoke to imitate their parents, a nightmarish prospect for many teenagers. Yet the twin studies discussed above indicate a role for the family environment. Thus, the data underscores the importance of intragenerational influences coming from sibs, friends, etc. This, of course, does not negate the importance of genetic influences. Parental influences on the acquisition of cigarette smoking behavior may be mediated by genetic influences on personality characteristics such as conscientiousness. The importance of these genetic influences on the maintenance of smoking may wane, however, and be replaced by others related to issues such as nicotine sensitivity. In sum, the volume provides many examples of how behavior genetic designs can be useful in the study of diverse questions related to the relative proportion of environmental and genetic influences on behavior, the stability of etiological factors and behavior across time, ethnic and gender differences, and so on. Blaine Ditto McGill
University Montreal Canudu
Book reviews
conceptual analysis of fear antecedents (Sartory), as well as a survey of the fascinating research on the measurement of stimulus prepotency and fear conditioning through startle modulation and other psychophysiological techniques (Hamm & Vaitl, Ghman). The contributions in the last section come back to major theoretical issues involved, such as the relation of arousal and affective valence to the startle reflex modulation (Lang, Bradley, & Cuthbert), the different responsivity of the startle reflex and skeletal reflexes to affective valence (Requin & Bonnet), emotion processing in anhedonia, as studied by startle modulation, and the value of the startle probe to investigate emotion and emotional disorders (Bradley & Vrana). The chapters vary in level, interest, and appeal. Together, they offer an excellent overview of this important approach to the study of emotion, and the variety of domains in which it has proven to be fruitful. The book provides a concise way to get solidly informed both about theory, research methods, and results that cannot easily be found together in another way.
University
Nice H. Frijda of Amsterdum The Netherlunds
Behavior Genetic Approaches in Behavioral Medicine. J.R. Turner, L.R. Cardon, and J.K. Hewitt (Eds.), Plenum Press, New York, 1995, pp. xvi + 273, $54.00. ISBN o-306-44969-2
This edited volume is an excellent review of the area. The chapters are well-written and are better integrated than is usually the case for edited books. Most of the material is presented in a manner which is accessible by advanced undergraduate and graduate students, yet contains enough detail and nuance for a professional audience. The book slices up the area in two different ways: chapters focusing on the use of behavior genetic approaches to understand specific clinical problems such as alcohol use, cigarette smoking, high blood pressure, cardiovascular reactivity to stress, obesity and eating disorders, as well as several chapters devoted to approaches for dealing with issues which cut across problems such as ethnic and gender differences, genetic influences on environmental measures, etc. Although all of the chapters should be useful to those interested in behavioral medicine and provide a distinctive slant on their area, some (e.g. the chapters on cardiovascular reactivity to stress) will probably be a bit more interesting to the general health psychology audience as the material is less likely to be reviewed elsewhere. Consistent with the raison d’etre of behavioral medicine, i.e. that health and illness need to be viewed from a perspective which includes physiological, behavioral, and social influences, the book emphasizes the use of behavior genetic techniques to study both genetic and environmental influences on health-related behavior. One thought which came to mind as I read the book was a comment by
218
Book reviews
Sandra Starr in her Presidential address to the Behavior Genetic Association a few years ago that the field of behavior genetics had in a sense ‘lost the battle but won the war’. That is, I believe that she was somewhat concerned about the future of the society, but only because the acceptance of behavior genetic techniques to elucidate both genetic and environmental influences on a wide range of behaviors had become so great as to induce investigators to attend non-behavioral genetic conferences and to submit their work to journals outside the behavior genetic field, e.g. in journals focusing on specific problems in the addictions, psychopathology, and health psychology (I confess to being one of the latter). While the authors’ attempts may not convince some die-hard environmentalists of the value of behavior genetic techniques, the authors try hard to make the point that behavior genetic analysis does not stop with the calculation of a heritability coefficient. In fact, it only really begins at that point. For example, with the exception of the determination of the actual mechanisms of the effect, the quantitative genetics of body weight might seem to be a fairly simple question. However, the chapters on the genetics of childhood body mass index and lifetime obesity focus on more complex issues such as the factors influencing the distribution of fat in the body and the stability of weight across the life span. Heritable influences on birth weight are considerable, but not particularly relevant to body mass index several years later. Genetic influences on early childhood body mass continue to affect weight for several years, with the periodic addition of new genetic influences. As discussed in the section on adiposity rebound, some of these may have greater relevance for the problem of adult obesity than others. The idea that behavior genetic analysis must deal with ‘moving targets’, that is, characteristics or behaviors which are constantly changing in a complex social and cultural matrix, is a recurring theme in the book. This underscores the fact that a heritability coefficient is really just an estimate (albeit an important estimate) of the proportion of variance due to heritable influences in a group at a particular point in time, and not an immutable characteristic. The chapters on cigarette smoking provide perhaps the best argument for the use of behavior genetic designs to understand environmental as well as genetic influences on health-related behavior. For example, the results of twin studies of the heritability of smoking are discussed by Heath and Madden in terms of the era in which they were conducted. The results were re-analyzed using comparable techniques, making it difficult to attribute different findings to differences in methodology. All of the studies produced evidence of significant genetic influence on both the acquisition and maintenance of cigarette smoking behavior. More interestingly, the authors also observed a significant influence of the family environment on cigarette smoking in more recent samples. This may reflect the fact that there are now social pressures against as well as for smoking. The presence of an influence of the family environment on smoking is striking given the general lack of such effects on personality (for which the bulk of the variance is explained by additive genetic and individual-specific environmental effects). In the following chapter, Rowe and Linver present a biosocial model for cigarette smoking which starts with a somewhat sociobiological interpretation of the most
219
Book reviewIs
common environmental explanation for the initiation of smoking, i.e. peer pressure. That is, smoking is compared to the display of a ‘self-handicapping’ characteristic. Although this may have certain adverse effects, their negative impact is overshadowed by the independence and ‘fitness’ this behavior supposedly displays to others. The sociobiology is not overplayed, however. A certain amount of evidence consistent with this viewpoint is cited (e.g. findings that blood testosterone level moderates social influences on smoking) and, more importantly, this provides an interesting basis to discuss environmental influences on smoking acquisition. The relatively low parent-offspring similarity in smoking is noted as support for the view that adolescents do not usually begin to smoke to imitate their parents, a nightmarish prospect for many teenagers. Yet the twin studies discussed above indicate a role for the family environment. Thus, the data underscores the importance of intragenerational influences coming from sibs, friends, etc. This, of course, does not negate the importance of genetic influences. Parental influences on the acquisition of cigarette smoking behavior may be mediated by genetic influences on personality characteristics such as conscientiousness. The importance of these genetic influences on the maintenance of smoking may wane, however, and be replaced by others related to issues such as nicotine sensitivity. In sum, the volume provides many examples of how behavior genetic designs can be useful in the study of diverse questions related to the relative proportion of environmental and genetic influences on behavior, the stability of etiological factors and behavior across time, ethnic and gender differences, and so on. Blaine Ditto McGill
University Montreal Canudu