Which is more important. What determines most of our behavior Which is more important? What determines most of our behavior? Our genes? Or our environment? Heredity versus the environment Nature vs. Nurture

Universal people communicate both verbally and nonverbally enforce rules of etiquette They avoid incest, fear snakes, and exchange gifts. Universal people demonstrate modesty in sexual behavior and bodily functions, even if they don’t wear clothes. Everywhere labor is divided by age and by gender. Men are more aggressive than women; women provide more child care. Every culture has tools Everywhere, people form beliefs about death and disease, they plan for the future. All cultures have taboos, including tabooed utterances. Sanctions exist for crimes against society, and mechanisms for dealing with theft, murder, and rape are universal. People everywhere recognize marriage They mimic, flirt, envy, empathize, joke, tease, They dance and make music

Genes: Our Codes for Life Chromosome DNA (deoxyribonucleic acid) Genes

Blue Eyes?

Twin and Adoption Studies Identical Versus Fraternal Twins Identical twins Fraternal twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Identical Versus Fraternal Twins

Twin and Adoption Studies Separated Twins U of MN studies on identical twins separated at birth- two Jims (hobbies, habits, dog’s name, son’s name)

Gerald Levey and Mark Newman, both: Work as volunteer firefighters Like the same beer (Budweiser) Are attracted to the same kinds of women Gerald worked in forestry, Mark worked for the city trimming trees (planned to go to school for forestry) Both liked to hunt, fish, watch John Wayne movies and eat Chinese food Both grew the same sideburns and mustaches Used the same speaking inflections and hand gestures

Can you find a twin in this class?

Anecdotal evidence “Virtual twins”

Twin and Adoption Studies Biological Versus Adoptive Relatives Genetic relatives Environmental relatives Are adopted children more like their biological parents or adoptive parents?

Well, it depends. Their personality traits (how outgoing they are, how friendly, their overall temperament) were much more similar to their biological parents. Environmental factors have almost no impact on your personality Children in the same family are often very different Do parents even matter?

Parents influence: Attitudes (such as toward education) Values Manners Faith Politics Less credit, less blame

Heritability “difference among people” How much of the variation among people can be attributed to genes

Heritability of various traits IQ: .22 at age 5, .54 - . 62 at old age Interests (art, science etc.) .36 Psychiatric illnesses: Schizophrenia (.80), alcoholism (.50 to .60) Religiousness: .11 to .22 Heritability of various traits

Heritability Group Differences Heritable differences between individuals does not imply heritable group differences

Heritability Nature and Nurture Influence of adaptation Nature and nurture work together Genes are self-regulating They react to the environment

Gene-Environment Interaction Genes and experience interact Evocative interactions Mom likes you better! 

Natural Selection and Adaptation Evolutionary psychology Natural selection Mutation Adaptation Fitness

Evolutionary Success Helps Explain Similarities Behaviors that contribute to survival are found throughout cultures

Why are children often afraid of the dark?

Evolutionary Success Helps Explain Similarities Outdated Tendencies Genetic traits which helped our ancestors survive may harm us today

Experience and Faculties Repeated experiences modify neural tissue. We can change our brains! When is the brain’s plasticity highest? Pruning Courtesy of C. Brune

Brain Development and Adulthood Brain development does not stop when we reach adulthood. Throughout our life, brain tissue continues to grow and change. A well-learned finger-tapping task leads to more motor cortical neurons (right) than baseline.

Peer Influence In many ways, peers play a larger role than parents in shaping our behavior. What causes people to start smoking? Like a certain type of music? Wear certain clothes? Talk the way they talk? Evolutionary perspective on peers? Ole Graf/ zefa/ Corbis

Differing preferences in partners An Evolutionary Explanation of Human Sexuality Natural Selection and Mating Preferences Differing preferences in partners Male preferences Female preferences

Men tend to look for: Physical attractiveness and a youthful appearance

A man’s ideal women would look like…

Women tend to look for: Maturity, dominance, status/affluence, and boldness

So a woman’s ideal man would look like…

Characteristics Characteristics Preferred by Males Preferred by Females 1. Kindness and 1. Kindness and understanding understanding 2. Intelligence 2. Intelligence 3. Physical attractiveness 3. Exciting personality 4. Exciting personality 4. Good health 5. Good health 5. Adaptability 6. Adaptability 6. Physical attractiveness 7. Creativity 7. Creativity 8. Desire for children 8. Good earning capacity 9. College graduate 9. College graduate 10. Good heredity 10. Desire for children 11. Good earning capacity 11. Good heredity 12. Good housekeeper 12. Good housekeeper 13. Religious orientation 13. Religious orientation

Critiquing the Evolutionary Perspective Backward theorizing Impact of social influence

Cultural Influences Humans have the ability to evolve culture. Culture is composed of behaviors, ideas, attitudes, values and traditions shared by a group.

Jason Reed/ Reuters/Corbis Variation Across Culture Cultures differ. Each culture develops norms – rules for accepted and expected behavior. Men holding hands in Saudi Arabia is the norm (closer personal space), but not in American culture. Jason Reed/ Reuters/Corbis

Variation Over Time Cultures change over time. The rate of this change may be extremely fast. In many Western countries, culture has rapidly changed over the past 40 years or so. This change cannot be attributed to changes in the human gene pool because genes evolve very slowly.

Culture and the Self If a culture nurtures an individual’s personal identity, it is said to be individualist, but if a group identity is favored then the culture is described as collectivist. A collectivist support system can benefit groups who experience disasters such as the 2005 earthquake in Pakistan. Kyodo News

Gender Differences in Aggression Men express themselves and behave in more aggressive ways than do women. This aggression gender gap appears in many cultures and at various ages. In males, the nature of this aggression is physical. In the U.S. the male to female arrest rate is 9 to 1. Men are more likely to support war as a solution to international problems

Why men don’t ask for directions vid.

In 2005, men accounted for 84% of the governing parliaments. Gender and Social Power In most societies, men are socially dominant and are perceived as such. In 2005, men accounted for 84% of the governing parliaments.

Gender Differences and Connectedness Young and old, women form more connections (friendships) with people than do men. Men emphasize freedom and self-reliance. - Playgrounds - How men stand Oliver Eltinger/ Zefa/ Corbis Dex Image/ Getty Images

A study of 30 countries, including the regions of Western Europe, Asia, South America, and Africa, found traits correlated with men to be: active, adventurous, aggressive, arrogant, autocratic, bossy, coarse, conceited, enterprising, hardheaded, loud, obnoxious, opinionated, opportunistic, pleasure-seeking, precise, quick, reckless, show-off, and tough Traits correlated with women included: affected, affectionate, appreciative, cautious, changeable, charming, dependent, emotional, fearful, forgiving, modest, nervous, patient, pleasant, prudish, sensitive, sentimental, softhearted, timid, and warm

The New Frontier: Molecular Genetics Molecular behavior genetics Genetics and diseases Genetics and ethics

The End

Definition Slides

= the study of the relative power and limits of genetic and environmental influences on behavior. Behavior genetics

= every non-genetic influence, from prenatal nutrition to the people and things around us. Environment

= threadlike structures made of DNA molecules that contain the genes. Chromosomes

DNA (deoxyribonucleic acid) = a complex molecule containing the genetic information that makes up the chromosomes. DNA (deoxyribonucleic acid)

= the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing a protein. Genes

= the complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes. Genome

= twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms. Identical Twins

= twins who develop from separate fertilized eggs = twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment. Fraternal Twins

= the proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied. Heritability

= the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity). Interaction

= the subfield of biology that studies the molecular structure and function of genes. Molecular Genetics

Evolutionary Psychology = the study of the evolution of behavior and the mind,using principles of natural selection. Evolutionary Psychology

= the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations. Natural Selection

= the random error in gene replication that leads to a change. Mutation