Chapter 4 - Nature vs. Nurture Flashcards
What is behavior genetics?
The study of how heredity and the environment can contribute to human differences.
What are genes?
Part of DNA molecules, found in chromosomes in the nuclei of cells.
Humans have 46 chromosomes in 23 pairs - half from the mother and half from the father.
Genes are not blueprints, they are molecules that direct the assembly of proteins that build the body. This genetic protein assembly can be turned on and off by the environment or other genes.
Any trait we see is a result of the complex interactions of many genes and countless other molecules.
What do behavior geneticists hope to do in the future?
Control variables. Can we design experiments to keep genes constant and vary the environment to see what happens? Or vary the genes in the same environment?
Discuss fraternal and identical twins.
Fraternal twins from separate eggs are no more genetically alike than other siblings.
Studies of twins in adulthood show that identical twins are more alike than fraternal twins in: personality traits such as extraversion and neuroticism, behaviors and outcomes such as divorce rate, and abilities such as overall intelligence test scores.
We can study the traits of identical twins as they grow up or if they were raised separately. Ex. Minnesota Twin Studies - identical twins that were raised in separate homes with different cultures and parenting styles still had very similar personalities, thinking styles, fears, attitudes, interests, intelligence, brain waves, and heart rate.
Are adopted children more similar to their adopted or their biological relatives?
Studies have been performed with adopted children for whom the biological relatives are known and adoptive children seem to be more similar to genetic relative than their environmental / nurture relatives.
Notes about parenting and differences in siblings.
Parenting influences things like religious and political beliefs, values, manners, attitudes, and habits.
Why are siblings so different?
Siblings only share half their genes. Genetic differences become amplified as people react to them differently. Families are slightly different to each child - the youngest has more older siblings and older, wiser, more tired parents.
Temperament is not caused by parenting. Most people do not see changes in temperament, or the general level and style of emotional reactivity.
What are the three general types of temperament?
Easy, difficult, and slow to warm up.
What is molecular genetics?
The study of the molecular structure and function of genes.
How do specific genes have an influence on behaviors? Researchers study families who have had a disorder across several generations and compare differences in affected versus unaffected individuals.
What is heritability?
The amount of variation in the population that is explained by genetic factors.
It does not tell us the proportion that genes contribute to the trait for any one person or what differences between groups is due to genes.
Ex. same upbringing and experiences but differences in shyness.
Physical and mental abilities develop in response to?
Experience.
Genetic traits influence the social environment which in turn affects behavior.
What is self-regulation? Give an example.
Genes turn each other on / off in response to environmental conditions.
Ex. shortened daylight triggers animals to change fur colors or to hibernate.
What is epigenetics? Give an example.
The environment acts on the surface of genes to alter their activity.
Ex. obesity in adults can turn off weight regulation genes in offspring.
Ex. infant rats denied of their mother’s normal licking had more epigenetic molecules that block access to the “on” switch for developing the brain’s stress hormone receptors.
The trait of being adaptable is built into the human genome. We have minds which allow us to change our behaviors in response to the environment to a greater degree than other species and we can shape our environment.
What is evolutionary psychology?
The study of how evolutionary principles help explain the origin and functions of the human mind, traits, and behaviors.
What was Balyaev and Trut’s artificial selection experiment?
Balyaev and Trut selected the most gentle, friendly foxes from a population and made them reproduce. They were able to shape these aggressive creatures into domesticated foxes, just as wolves were once shaped into dogs.
Why does stranger anxiety develop between the ages of 9 and 13 months?
Humans learn to walk around this time, and infants who use this new ability to walk away from their family and toward a lion might not have survived to produce unlike those who clung to their parents.
What are some mating differences in males and females?
Generally men think more about sex and are more likely to think casual sex is acceptable.
Why might natural selection have resulted in greater male promiscuity?
Promiscuity in men promotes the continuation and spread of their genes, and there is little risk to doing this.
Promiscuity in females would not greatly increase the number of babies and has greater survival costs - childbirth can be dangerous.
Men seek women will fuller figures to make sure they’re not too young / old to have children. Women seek males with loyal behavior to ensure they stick around to provide for their children.
What is the nature versus nurture debate?
How much of our personality / traits is inborn / determined by genes and how much do we get from our environment / peers / etc.
What is growth and pruning?
At birth, we have more synapses than we need. Our brain decides which to keep through experiences. To make our well-used brain pathways work better, the unused connections are pruned away. If certain abilities are not used, they will fade.
Is parenting a powerful environmental influence on development?
The power of parenting is clearest at the extremes - severe abuse and neglect.
Non-abusive “average” parents should ease off on the both blame and credit they assume for how their kids turn out.
Children of warm supportive parents feel better about themselves and are less hostile.
What is the effect of peer influence on development?
Apparent conformity could be a selection effect - people are friends because they want to be with other like them. Ex. smoking.
Interaction with peers can teach new social skills.
Parents may indirectly select peers by selecting school and neighborhoods.
What do parents influence and what do peers influence?
Parents influence education / career path, religious and political views, values, and self-discipline.
Peers influence cooperation skills, music, clothing, fun, good and bad habits, and popularity.
What are some cultural influences on development?
Nature of culture - culture refers to the patterns of ideas, attitudes, values, lifestyle, habits, and traditions shared and passed on by a group of people.
Variation across culture - every culture has norms - standards for acceptable, expected behaviors. Ex. wearing shoes in house, greetings, etc.
Examples of changes in cultural variation over time - language changes in vocabulary and pronunciation, quickened pace of life, increased gender equality, less sleep, less in-person socialization, increased technology, people marry more for love and expect less romance.
There cultural changes happen too fast to be rooted in genetic change.
Culture shock - feeling lost about what behaviors are appropriate.
What is an individualist culture?
A culture that values independence. These cultures promote personal ideals, strengths, goals, competition with other leading to individual achievement, and unique personal identity.
What is a collectivist culture?
A culture that values interdependence. These cultures promote group and societal goals and duties, blending into a group, and identity and achievements are attributed to mutual support.
