Chapter 3 (1) Summary

Chapter 3 (1) Summary - C HAPTER 3 (SUMMARY): THE NATURE...

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CHAPTER 3 (SUMMARY): THE NATURE AND NURTURE OF BEHAVIOR Overview To what extent are we shaped by our heredity and to what degree by our life history? The conclusions—that nature is crucially important and that nurture is crucially important—are central to today’s psychology. Genes provide the blueprints that design both our universal human attributes and our individual traits. Evolutionary psychology sheds light on what’s universal, and behavior genetics on our differences. Evolutionary psychologists study how natural selection favored behavioral tendencies that contributed to the survival and spread of one’s genes. For example, in explaining gender differences in sexual behavior, they argue that women most often send their genes into the future by pairing wisely, men by pairing widely. Critics maintain that evolutionary psychologists make too many hindsight explanations and underestimate the role of culture. Behavior geneticists explore individual differences. By using twin, adoption, and temperament studies, they assess the heritability of various traits and disorders. Their research indicates that both nature and nurture influence our life courses. We are products of interactions between our genetic predispositions and our surrounding environments. Molecular geneticists’ search for genes that put people at risk for genetically influenced disorders has potential benefits as well as risks. Although genetic influences are pervasive, so are environmental influences. Nurture begins in the womb as embryos receive differing nutrition and varying levels of exposure to toxic agents. Sculpted by experience, neural connections multiply rapidly after birth. Peers powerfully socialize children and are important in learning cooperation, for finding the road to popularity, and for inventing styles of interaction among people of the same age. Cultural groups evolve norms or rules that govern members’ behaviors. They vary in their requirements for personal space, their expressiveness, their pace of life, and their child-rearing practices. Differing sex chromosomes and differing concentrations of sex hormones lead to significant physiological sex differences. Yet, gender differences vary widely depending on cultural socialization. Cultural variations in gender roles demonstrate our capacity for learning and adapting. Both social and cultural factors contribute to gender identity and gender-typing. Genes: Our Biological Blueprint The composition and physical location of genes. When egg and sperm unite, the 23 chromosomes from the egg pair with the 23 chromosomes from the sperm. Each chromosome is composed of a coiled chain of a molecule called DNA (deoxyribonucleic acid). DNA is in turn composed of thousands of genes, the biochemical units of heredity. They provide the blueprint for protein molecules, the building blocks of our physical and behavioral development. Our genes are composed of biochemical letters called nucleotides. Human genome researchers have discovered the common sequence of the 3.1 billion letters
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Chapter 3 (1) Summary - C HAPTER 3 (SUMMARY): THE NATURE...

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