Chromosomes
- contains many genes
- molecule of DNA
- every cell has 46 chromosomes (except egg and sperm)
Genotype and phenotype
•Genotype -specific genetic makeup -perform with birth -never change Phenotype -observable characteristics -can be changed by other genes, envronment
- Heritability
* Heritability coefficient
- How much of the variation in a characteristic within a population can be attributed to genetic differences
- Estimate of how much of characteristic is due to genetic factors
Concordance or co-occurrence
• higher concordance rate: people are more likely related to one another
• how study?
- twin study, adoption study
- result: adopted children frequently more like biological parents
identical twins more similar even they reared apart
Polygenic transmission
multiple gene pairs influence phenotype
Genetic Engineering
• Recombination DNA procedures
- enzymes cut DNA
- combined with DNA from another organism
-inserted into host cell
• Gene knockout
- particular function of gene is eliminated
• Problem
- few behaviors are controlled by single gene
Reaction range
- refers to how people have different reactions and attributes, although they had the same stimuli and environment as others.
- for example, two twins can grow up in the same environment, yet IQs can be vastly different
- reaction range may cover 15-20 IQ points
Behavior genetics & personality
• Study: is there a genetic component to our personality • Need to study - genetic contribution - shared family environment - unique personal experience • How to study - identical twins reared
Evolution
• evolutionary psychology
- How behavior and tendencies have evolved in response to environmental demands
• evolution
- change over time in frequency with which genes occur within an interbreeding population
• mutation
- create genetic variation, making evolution possible
- can be passed to offspring
Adaptions
• adaptions
- broad: learn language, reason logically
- domain-specific: solve particular problem(mate selection)
Evolutionary personality theory
• found universally
- extraversion
• help achieve 2 goals
- survival & reproduction
Mating system
People look for gender to have offspring. Gender with highest parental investment (usually female) are more popular and more discriminating in mate selection.
Monogamous
- Two parents have equal parental investment
* Little sexual dimorphism between males and females
- Polyandry
- Polygynous
- Polygynandry
- one female - many males
- one male - many females
- many male and females
Initial attraction
• physical proximity
- people are attracted by who are similar to them
- best indicator of whom we will meet
• mere exposure effect
- repeated exposure to a stimulus increases our liking to it
Two way of helping another
•cooperation
- (e.g.) cooperating to achieve a goal
•altruism
- one individual helps another but there are costs involved
- (e.g.) putting oneself in danger to help aother
Two theories of altruism
- Kin selection
* Reciprocal altruism
Prosocial behaviour
- socialization: children act more prosocially if taught empathy
- cultural influence: india
Aggression
•why aggression?
-evolutionarily: protect mate, food, territory, young
–intra-species: establishing dominant position, sexual jealousy & homicide
Evolutionary fallacies
•Genetic determinism: can’t be changed
-In fact: genes work through the environment, environment often determines placement; important pursuit: understanding interaction b/t biology and experience, importance of culture, environment, biology
•Social Darwinism: survival of the fittest
-In fact: Darwin did not claim “s o t f”; strong do not have right to exploit the weak
•Defending the status quo: evolution gave us a trait that must be good
-“nature” is not a metric of what is morally right
How to quell or solve aggression?
•Adaptive purpose for aggression (evolution) -divide limited resources -forming social alliances •Dominance hierarchy -set access to resources
