Nature vs. Nurture (via) or “Why we are who we are” Dr. Swoap Intro to Psychology

Fundamental Question How are we shaped by both our heredity and life history?

Behavior Genetics Attempts to explain individual differences –Twin studies (U of M) (see Fig. 6.3) –Adoption studies

Behavior Genetics –Heritability: The proportion of variation among individuals that we can attribute to genes –Temperament and Personality: Were you born that way? Video Sci Amer #23 “Bringing up Monkey”

Evolutionary Psychology How does natural selection work with regards to behavior? –Survival-oriented behavior is passed on

Evolutionary Psychology and sexual behavior Survey: –Question 1: A sunny afternoon on vacation… You are relaxing by the ocean. A person you don’t know, but whom you think is really good- looking, comes up to you and says: “I find you really attractive. I’d like to sleep with you tonight.” What would you do/say? –Question 2: How often do you think about sex?

How often do you think about sex?

Amidst the festivities of a grand party, a young guy notices a strikingly beautiful girl and is immediately obsessed…. He approaches her and begins to flirt boldly…. She tries to deny him, but soon is flattered by his attention and finds him quite attractive… Love in bloom

By the time he departs the scene, with just a few kisses, these two have exchanged fewer than a hundred words; yet, both are swooning with sensations of falling, desperately, in love. All their mental processes – thinking, planning, goals, feelings, and motivations – have been suddenly transformed….these brains have been completely gripped by this brief encounter. Romantic feelings kindle rapidly….

In the hours after this meeting, these two can not stop thinking about each other The intensity of desire is so strong that each would happily forego food, sleep, comfort, and all competing pleasures, simply to be in each other’s presence again Shakespeare ( 1595) was dramatizing one of the normal tensions of adolescence and development of sexual motivations. Longing, obsession, and desire…

SEX: Nature via Nurture

Energizing and directing arousal Interplay of internal and external stimuli Internal: Hormones, brain structures, neurotransmitters, imagined stimuli External: Environmental and sociocultural factors

Environmental Influence –Five ways we are shaped along with genes: 1. Prenatal environment 2. Early experience 3. Peer Influence 4. Culture 5. Gender influences Keep in mind that our genes influence the nurture and experiences we seek. (My children and their temperaments influence my parenting.)

Environmental Influence –Five ways we are shaped along with genes: 1. Prenatal environment influences?

2. Early experience Multiple studies emphasize the importance of stimulating experience &/or touch: Both enhance brain development (as does physical activity) Rosenzweig et al., 1972)

2. Early experience -- continued Multiple studies emphasize the importance of stimulating experience &/or touch: Both enhance brain development (as does physical activity) (massage therapy with preemies)

Environmental Influence –Five ways we are shaped along with genes: 3. Peer influence factors? (e.g., man in elevator)

4. Culture –Examples? Food preferences, personal space, aggression/violent behavior Obesity –Cultural influences combined with a genetic predisposition to store fat

Obesity Trends* Among U.S. Adults (*BMI  30, or ~ 30 lbs overweight for 5’4” woman) *Go to CDC slide show on “Obesity trends”

BODY MASS ENERGY INENERGY OUT Increase in availability of high density foods (sugar/fat are cheap) Increase in size Decrease in cost Decrease in work- related activities Decrease in activity of daily living Genetic predisposition to store fat Nature via Nurture in Obesity

“Our jeans no longer fit our waist because our genes no longer fit our environment”

5. Gender Influences Why are you a male/female? (Besides the obvious reasons…) Gender is a social category of being male or female.

Gender development starts early Is it a boy or a girl???

Interactive model of Gender Development Parenting style Child’s traits & Biological factors Socio-cultural factors

Socialization and gender Differential gender socialization Gender and culture –(e.g., rites of passage, expected behaviors)