2.3 Genes & Evolutionary Psychology Text pages 66-77 Mr. Fetzner Psychology Power Point Notes 2.3 Genes & Evolutionary Psychology Text pages 66-77 NLshop/ Fotolia.com

Fact or Falsehood? false false true true true In many places around the world, females are more likely than males to initiate sexual activity. Seven weeks after conception, males and females remain anatomically indistinguishable. Fact or Falsehood? false false If after a worldwide catastrophe only Icelanders or Kenyans survived, the human species would suffer a huge reduction in its genetic diversity. Compared with Westerners, people in Japanese cultures exhibit greater concern for social harmony and loyalty. true Click to reveal each question, then the answer. true Even when families discourage traditional gender-typing, children still organize themselves into boy worlds and girl worlds, each guided by rules for what boys and girls do. true

Behavior Genetics Behavior Genetics: the relative power (& limits) of genetic and environmental influences on behavior. Environment: Every nongenetic influence, from prenatal nutrition to the people and things around us Heredity: The genetic transfer of characteristics from parents to offspring Behavior genetics: Study of the relative power and limits of genetic and environmental influences on behavior

Genes: Our Codes of Life Chromosomes: Threadlike structures made of DNA molecules that contain the genes DNA (deoxyribonucleic acid): Complex molecule containing the genetic information that makes up the chromosomes Genes: Biochemical units of heredity that make up chromosomes; segments of DNA capable of synthesizing proteins Genome: All the genetic material in an organism’s chromosomes When genes are expressed, they provide the code for creating the proteins that form our body’s building blocks Figure 2.29 The life code The nucleus of every human cell contains chromosomes, each of which is made up of two strands of DNA connected in a double helix. Genes are DNA segments that, when expressed (turned on), direct the development of proteins that influence a person’s individual development.

Identical Versus Fraternal Twins Identical twins: Develop from a single fertilized egg that splits in two, creating two genetically identical organisms. Identical twins share the same conception and uterus, and usually the same birth date and cultural history

Fraternal Twins Fraternal twins: Develop from separate fertilized eggs Genetically no closer than brothers and sisters, but they share a prenatal environment Studies of twins in adulthood show that identical twins are more alike than fraternal twins in: Having disorders, such as autism spectrum disorder Personality traits such as extraversion (sociability) and neuroticism (emotional instability).

Twin and Adoption Studies Separated Twins Similarities found in identical twins despite being raised in different homes: Personality, styles of thinking and relating Abilities/intelligence test scores Attitudes Interests, tastes Specific fears Brain waves, heart rate

Does the home environment have any impact? Adoption Studies Biological Versus Adoptive Relatives Studies conducted with adopted children for whom the biological relatives are known Findings: Adopted children seem to be more similar to their genetic relatives than their adoptive relatives The environment shared by a family’s children has virtually no discernible impact on their personalities. Does the home environment have any impact?

Twin and Adoption Studies Biological Versus Adoptive Relatives Despite the strong impact of genetics on personality, parenting has an influence on: Religious beliefs Values Manners Attitudes Politics Habits

HOW DO HEREDITY AND ENVIRONMENT WORK TOGETHER? Genes and environment–nature and nurture–work together Genes are self-regulating; rather than acting as blueprints that lead to the same result no matter the context, genes react Genes and experience interact Epigenetics: The study of environmental influences on gene expression that occur without a DNA change

EPIGENETICS INFLUENCES GENE EXPRESSION Life experiences beginning in the womb lay down epigenetic marks—often organic methyl molecules—that can affect the expression of any gene in the associated DNA segment. (From Champagne, 2010.) Figure 2.31

Evolutionary Psychology: Understanding Human Nature Evolutionary psychology: The study of the evolution of behavior and the mind, using principles of natural selection. Evolutionary psychologists use Charles Darwin’s principle of natural selection to understand the roots of behavior and mental processes Natural selection: The principle that those chance inherited traits that better enable an organism to survive and reproduce in a particular environment will most likely be passed on to succeeding generations. Nature has indeed selected advantageous variations from the new gene combinations produced at each human conception plus the mutations (random errors in gene replication) that sometimes result. But especially in humans, genes and experience together wire the brain.

Natural Selection and Adaptation Genes selected during our ancestral history give us a great capacity to learn and therefore to adapt to life in varied environments. The tight genetic leash that predisposes a dog’s retrieving, a cat’s pouncing, or a bird’s nesting is looser in humans. Adaptive flexibility in responding to different environments contributes to the ability to survive and reproduce.

Evolutionary Psychology: How Natural Selection Works Begin with a species’ genome, which contains a variety of versions of genes that shape traits. Conditions make it difficult for individuals with some traits (some versions of those genes) to survive long enough to reproduce. Other individuals thus have their traits and genes “selected” to spread in the population.

In what ways might this be problematic? Understanding Human Nature Evolutionary Success Helps Explain Similarities Our Genetic Legacy As success-enhancing genes were selected over time, behavioral tendencies and thinking and learning capacities emerged that prepared our Stone Age ancestors to survive, reproduce, and send their genes into the future. As inheritors of this prehistoric genetic legacy, we are genetically predisposed to behave in ways that promoted our ancestors’ surviving and reproducing, ways that may be mismatched with our contemporary lifestyle. In what ways might this be problematic?

Evolutionary Psychology: Understanding Human Nature Evolutionary Success Helps Explain Similarities Evolutionary Psychology Today Darwin’s theory of evolution has become one of biology’s organizing principles The theory lives on in the second Darwinian revolution, the application of evolutionary principles to psychology Darwin anticipated this, foreseeing “open fields for far more important researches. Psychology will be based on a new foundation.”