It’s the Neurons, Stupid; Or Is It?

Although neuroscience is certainly making inroads into psychology, the profession is far from abandoning its traditional tools and methods, and it remains to be seen how neuroscience will be integrated into psychological science. Wexler proposes a workable balance among neuroscience and other approaches to human psychology and moves boldly forward to explain how neuroscience can illuminate history, culture, and current affairs. Though creative and imaginative, his thesis is also speculative and controversial.

Wexler sweeps confidently through topics ranging from brain neuroanatomy to cognitive dissonance, psychoanalysis, the Crusades, the Holy Inquisition, immigration, bereavement, and the clash of civilizations. He fearlessly suggests that discoveries about the brain, cognition, and behavior could play an essential role in understanding major historical developments. His main thesis is that the consolidation of brain structures in the course of human development and their relative rigidity in mature adults could be at the root of major social and political upheavals. This makes for fascinating reading, as Wexler stretches to connect a vast array of disparate dots that defy easy linkage.

The book builds logically from a foundation of known facts about the brain, its anatomy, and its functions. This knowledge is then applied to a widening array of topics, beginning with individual psychology and ending with the problems of globalization and the current unprecedented and seemingly unavoidable conflict among the world’s cultures. Wexler begins with a useful review of some basic findings about the human brain, its evolutionary bases, and its development. He emphasizes that the brain is modular (various parts of the brain serve particular purposes such as speech, memory, etc.) and plastic (its various parts can take over some of each other’s functions); that the development of the brain is influenced by environmental factors; and that as the brain matures, it becomes less susceptible to change.

After the introduction to basic neuroscience, the book addresses specific examples of the environmental shaping of brain functions. Chapter 2 considers the effects on brain structure of sensory deprivation and sensory enrichment, citing studies that suggest that the survival of brain cells and the formation of cell interconnections depend on the type and amount of stimulation that the organism receives from its environment. Chapter 3 follows this line of thought with evidence that such stimulation contains a social component that affects brain development.

Moving to a more general level, Wexler proposes that the process of child rearing can be thought of as a kind of symbiotic relationship wherein parents provide their offspring with specific brain functions that the offspring lack (such as memory, planning, organization, and strategy). Thus, parenting and maturation are reconceptualized in terms of brain functions that parents fulfill for their children and that the children acquire as they advance to adulthood.

Part II addresses the neural bases of ideological commitments. Chapter 4 argues that internal brain structures are most sensitive to environmental influence (hence are most malleable and capable of learning) in early childhood, when humans are least capable of acting, and are least sensitive to such influences in adulthood, when people are most capable of acting. Wexler cites a diverse body of evidence that indicates that people react with stress to a fundamental change in their life circumstances, such as the loss of a loved one, or to information inconsistent with their prior beliefs. Wexler’s point is that just as the brain structure loses plasticity as the brain matures, people’s beliefs become increasingly resistant to change. Encounters with ideas inconsistent with one’s beliefs therefore cause considerable stress and tension for the individual.

According to Wexler, this stressful challenge to beliefs is exactly what happens in the confrontation between different cultures. At this point, Wexler has left the domain of neuroscience and psychology and moved on to the realm of history and anthropology. He explores the scope and content of intercultural differences, the importance of ceremonial objects, and the ambivalent fascination with otherness. Extrapolating from historical events that range from Captain Cook’s demise in Hawaii and the Rwandan conflict between the Hutus and the Tutsis to the Albigensian heresy and the Inquisition, Wexler asserts that “differences in belief systems can …occasion intercultural violence, since concordance between internal structure and external reality is a fundamental human neurobiological imperative.” The epilogue extends this discussion to the contemporary world situation, addressing threatened indigenous cultures that cling “desperately to vanishing traces of familiar habitat,” the invasion of national cultures by foreign media, and the role of the United States in managing intercultural conflicts within its boundaries and in the world at large.

Although Wexler begins his discussion with a firm grounding in neuroscience, he ends up discussing global political and cultural events that have at best a tenuous connection to neuroscience. Wexler’s basic thesis that the rigidity of belief systems and the resulting intercultural violence have their roots in the way our brains function is suggestive but at this point far from compelling. Nevertheless, a bold theory has generative power. Wexler’s analysis has numerous implications for possible subsequent research. For instance, it should be of interest to use the tools of neuroscience to assess brain rigidity; that is, to measure the degree to which a person’s stable functional brain structures have been formed and flexibility has been lost. Then researchers can examine to what extent an individual’s “rigidity index” correlates with the individual’s stage of development and maturation, the amount of stress the person experiences when confronting novel and conflicting beliefs, and the proclivity to respond with tension and aggression in situations of intercultural conflict. It should also be of interest to relate such biologically defined rigidity to sociocognitive indices of mental rigidity, such as the need for cognitive closure, and to explore the neural implications of the many behavioral findings concerning situational determinants of flexibility loss and the contextual conditions for people’s closed- and openmindedness.

It is, finally, of interest to consider this book’s implications for neuroscience as an approach to psychology. Can we find a productive method of merging biological, social, cognitive, and behavioral findings? Wexler might be right that the addition of neuroscience to traditional approaches could lead to profound insights into the way humans function, develop, and react to their environments. Indeed, Wexler’s important message could be that psychological neuroscience may thrive and develop only through interaction and convergence with alternative approaches to psychology and the rich tapestry of insights and phenomena they have to offer.