Chapter 3: Gene, Environment, and Behavior

Genetic Influence on Behavior

• Genotype: the specific genetic makeup of the individual
• Phenotype: the individual’s observable characteristics
• Chromosome: is a double-stranded and tightly coiled molecule of deoxyribonucleic acid (DNA)
• Genes: biological units of heredity
• Alleles: alternative forms of a gene that produce different characteristics
• Dominant: the particular characteristic that it controls will be displayed
• Recessive: the characteristic will not show up unless the partner gene inherited from the other parent is also recessive
• Polygenic Transmission: a number of gene pairs combine their influences to create a single phenotypic trait
• Epigenetics: Changes in gene expression that are independent of the DNA itself and are caused instead by environmental factors
• Family Studies: researchers study relatives to determine if genetic similarity is related to similarity on a particular trait
• Adoption Study: in which people who were adopted early in life are compared on some characteristic with both their biological parents, with whom they share genetic endowment, and with their adoptive parents, with whom they share no genes
• Twin Studies: which compare trait similarities in identical and fraternal twins
• Concordance:  trait similarity
• Heritability Coefficient: estimates the extent to which the differences, or variation, in a specific phenotypic characteristic within a group of people can be attributed to their differing genes

Adapting to the Environment: The Role of Learning

• Adaptive Significance: how behavior influences an organism’s chances of survival and reproduction in its natural environment.
• Shared Environment: the people who reside in them experience many of their features in common
• Evocative Influence:  a child’s genetically influenced behaviors may evoke certain responses from others

Evolution, Culture, and Behavior

• Biologically Based Mechanisms:  enable us to take in, process, and respond to information, predisposing us to behave, to feel, and even to think in specific ways

• Evolution: change over time in the frequency with which particular genes and the characteristics they produce occur within an interbreeding population

• Natural Selection: characteristics that increase the likelihood of survival and reproduction within a particular environment will be more likely to be preserved in the population and, therefore, will become more common in the species over time

• Adaptations: physical or behavioral changes that allow organisms to meet recurring environmental challenges to their survival, thereby increasing their reproductive ability.

• Evoked Culture: Cultures may themselves be products of biological mechanisms that evolved to meet specific adaptation challenges faced by specific groups of people in specific places at specific times.

• Sexual Strategies Theory: mating strategies and preferences reflect inherited tendencies, shaped over the ages in response to different types of adaptive problems that men and women faced

• Social Structure Theory:  maintain that men and women display different mating preferences not because nature impels them to do so but because society guides them into different social roles.

• Strategic Pluralism: the idea that multiple- even contradictory- behavioral strategies

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