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Explore genetic influences on behavior and evolutionary perspectives in psychology.
The basic cycle of evolutionary change.
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Behavioral genetics examines how genetic factors influence psychological traits, behaviors, and mental disorders. This field investigates the heritability of characteristics, gene-environment interactions, and the biological basis of individual differences.
DNA and Genes: - DNA: Double helix structure containing genetic information - Genes: Specific segments of DNA that code for proteins - Alleles: Alternative forms of genes - Genotype vs. Phenotype
Heredity Mechanisms: - Mendelian inheritance: Dominant/recessive patterns - Polygenic traits: Multiple genes influence single traits - Gene-environment interaction: Heritability varies across environments
Heritability Estimates: - Twin studies compare monozygotic vs. dizygotic twins - Adoption studies separate genetic from environmental effects - Heritability coefficients range from 0-1.0
Molecular Genetics: - Genome-wide association studies (GWAS) - Gene sequencing and identification - Epigenetics: Environmental influences on gene expression
Behavioral Genetics: - Twin and adoption designs - Family studies - Breeding studies in animals
Applications: - Personalized medicine in psychiatry - Genetic counseling - Ethical considerations
Evolutionary psychology applies principles of natural selection to understand mental processes and behavior.
Core Premise: Psychological adaptations evolved to solve ancestral problems.
Key Concepts: - Adaptation: Traits that enhance survival and reproduction - Natural Selection: Differential survival/reproduction of traits - Fitness: Reproductive success - Environment of Evolutionary Adaptedness (EEA): Ancestral environment shaping adaptations
Common Adaptive Problems: - Survival: Avoiding predators, finding food - Mating: Mate selection, competition - Parenting: Investment in offspring - Social: Cooperation, competition, kin selection
Critiques and Limitations: - Just-so stories (speculative explanations) - Difficulty testing hypotheses - Modern environments differ from ancestral
Mating Strategies: - Short-term vs. long-term mating - Sex differences in mating preferences - Parental investment theory
Altruism and Cooperation: - Kin selection: Helping genetic relatives - Reciprocal altruism: Helping with expectation of return - Group selection: Selection at group level
Aggression: - Evolutionary functions of aggressive behavior - Gender differences in aggression - Status competition
Emotion and Motivation: - Evolutionary functions of emotions (fear as alarm, disgust as disease avoidance) - Universal emotions across cultures - Motivation systems (approach vs. avoidance)
Diathesis-Stress Model: - Genetic vulnerability interacts with environmental stressors - Explains why disorders develop in some but not all
Epigenetics: - Environmental factors influence gene expression without changing DNA sequence - Methylation, histone modification - Transgenerational effects possible
Differential Susceptibility: - Individuals vary in genetic sensitivity to environment - Orchid vs. dandelion children concept
Plasticity: Genetic expression can change over lifespan
The three ways genes and environments correlate.
| Mechanism | Example | |
|---|---|---|
| Passive | Parents provide both genes and environment | Musical parents provide instruments and 'musical' genes |
| Evocative | Individual's traits elicit environmental responses | A happy baby receives more social stimulation |
| Active | Individual seeks out matching environments | An athletic child joins sports teams |
4 questions to test your understanding of this topic
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Buss, D. M. (2019). Evolutionary Psychology: The New Science of the Mind. Routledge (6th ed.).
Nesse, R. M., & Williams, G. C. (2019). Why We Get Sick: The New Science of Darwinian Medicine. Times Books.
Plomin, R. (2018). Blueprint: How DNA Makes Us Who We Are. MIT Press.
Turkheimer, E. (2000). Three Laws of Behavior Genetics and What They Mean. Current Directions in Psychological Science, 9(5), 160-164.
Cosmides, L., & Tooby, J. (2013). Evolutionary Psychology: New Perspectives on Cognition and Motivation. Annual Review of Psychology, 64, 201-229.
Caspi, A., & Moffitt, T. E. (2006). Gene-Environment Interactions in Psychiatry. Nature Reviews Neuroscience, 7(7), 583-590.
Meaney, M. J. (2010). Epigenetics and the Biological Definition of Gene × Environment Interactions. Child Development, 81(1), 41-79.
Belsky, J., & Pluess, M. (2009). Beyond Diathesis Stress: Differential Susceptibility to Environmental Influences. Psychological Bulletin, 135(6), 885-908.
Harden, K. P. (2021). The Genetic Lottery: Why DNA Matters for Social Equality. Princeton University Press.
