Nature Vs. Nurture

Response to Critique by Evolutionary Psychologists

Evolutionary psychologists argue that we need to test behaviors that expound evolutionary principles. Evolutionary psychologists remind us how we have adapted, but do not dictate how we ought to be. Males and females are more alike than different, and if we study these differences we can establish their causes.

Critiquing the Evolutionary Perspective

Evolutionary psychologists take a behavior and work backward to explain it in terms of natural selection. Evolutionary psychology proposes genetic determinism and undercuts morality in establishing society. Where genders are unequal, gender preferences are wide, but when they are closely equal, preferences narrow down.

Gene

Segment of DNA containing the code for a particular protein; determines our individual biological development

Nature and Nurture

Some human traits are fixed, such as having two eyes. However, most psychological traits are liable to change with environmental experience Genes provide choices for the organism to change its form or traits when environmental variables change. Therefore, genes are pliable or self-regulating. So identical twins can allow differing experiences to help shape an independent personality.

Siblings Raised Together

Studies show that biologically related children turn out differently even when raised together. (genetic) Adopted siblings raised together are typically not similar in qualities such as personality, weight and learning disabilities. (genetic) Prenatal stress of the mother, particularly late in pregnancy has predicted emotional and behavioral problems in children at age four. (environmental)

Evolutionary Psychology

Studies why we as humans are alike. In particular, it studies the evolution of behavior and mind using principles of natural selection. The following traits would benefit humans in that they would provide an advantage for survival and reproduction: -The mental capacities for acquiring language. -The ability to infer emotion in others and to cooperate with others. - The preference for healthier, more fertile mates

Behavioral Genetics

Study our differences and weigh the relative effects of heredity and environment on behavior.

Twin and Adoption Studies

Studying the effects of heredity and environment on two sets of twins, identical and fraternal, has come in handy.

Gender Schema Theory

Suggests that we learn a cultural "recipe" of how to be a male or a female, which influences our gender- based perceptions and behaviors.Nature

Psychological Differences Between the Sexes

The average man is 5x more likely to successfully commit suicide or suffer alcohol dependence than the average woman. The average man is more likely to develop autism, ADHD or personality disorder than the average woman.

Physical Differences Between the Sexes

The average...than the average man. •woman begins puberty 2 years earlier •woman lives 5 years longer •woman has 70% more body fat and tend to carry it in different areas of the body •woman has 40% less muscle •woman is 5" shorter •woman is far less likely to be colorblind •woman is doubly vulnerable to depression and anxiety •woman's risk of developing an eating disorder is 10x greater

Heritability

The calculation of the environmental contribution of the expression of genes The amount a trait can vary based on how we express our genes The amount of trait variation that is expressed in the difference in biology. Not related to genetics or parents.

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. >Suggest that our behaviors are given environmentally.

Variations 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.

Human Traits

A number of human traits have been identified as a result of pressures afforded by natural selection. >Why do infants fear strangers when they become mobile? > Why do people fear snakes, bugs, and not electricity and guns? > How are men and woman alike?

Separated Twins

A number of studies compared identical twins reared separately from birth, or close thereafter, and found numerous similarities - Personality - Intelligence - Ability - Attitude - Interests - Fears - Brain waves - Heart Rate

Adoption Studies

Adoption studies, as opposed to twin studies, suggest that adoptees (who may be biologically unrelated) tend to be different from their adoptive parents and siblings Adoptive studies strongly point to the simple fact that biologically related children turn out to be different in a family.

DNA

All of the building blocks of what we can be as a species Spiraling

Natural Selection

An evolutionary process through which adaptive traits are passed on to ongoing generations because these traits help animals survive and reproduce.

Culture Variation Over Time

Culture changes over time. the rate of this change may be extremely rapid. in many western countries, culture has rapidly changed over the last 40 years. His change cannot be attributed to changes in the human gene pool because genes evolve very slowly. ex: woman's roles

Gender Development

Based on genetic makeup, males and females are alike, since the majority of our inherited genes (45 chromosomes are unisex) are similar. Gender is determined by only one chromosome. Males and females differ biologically in body fat, muscle, height, onset of puberty, and life expectancy.

Biology of Sex

Biological sex is determined by the twenty-third pair of chromosomes. If XX then a female is produced, or if XY, then a male child is produced.

Brain Development and Adulthood

Brain development does not stop when we reach adulthood. Throughout our life, brain tissue continues to grow and change.

Artificial Selection

Breeding organisms with specific traits in order to produce offspring with identical traits.

Peer Influence

Children, like adults, attempt to fit into a group by conforming. Peers are influential in such areas as learning to cooperate with others, gaining popularity, and developing interactions.

Chromosomes

Contains DNA and are situated in the nucleus of the cell

Developmental Similarities Across Groups

Despite diverse cultural backgrounds, humans are more similar than different in many ways. We share the same genetic profile, life cycle, capacity for language, and biological needs.

Experiences and Faculties

Early experiences during development in humans shows remarkable improvements in music, languages and the arts.

Experience and Brain Development

Early postnatal experiences affect brain development. Rosenzweig et al. (1984) showed that rats raised in enriched environments developed thicker cortices than those in impoverished environment.

Gene-Environment Interaction

Genes can influence traits which affect responses, and environment can affect gene activity. A genetic predisposition that makes a child restless and hyperactive evokes an angry response from his parents. A stressful environment can trigger genes to manufacture neurotransmitters leading to depression. Genes and environment affect our traits individually, but more important are their interactive effects.

Traits That Show More Heritability Than Others

Height Temperament >refers to a person's stable emotional reactivity and intensity. Identical twins express similar temperaments, suggesting heredity predisposes temperament. As environments become more similar, heredity as a source of difference become more important (since difference due to environment has decreased).

Gender Identity

How a person views himself or herself in terms of gender.

Cultural Influences

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

Community (individualism vs collectivism)

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.

Twin Studies

If we assume that an identical twin, shares 100% of the genetic material of its sibling, and that a fraternal twin shares 50% of the genetic material with its sibling then we can calculate how much of an expressed trait (in the same environment) between them is attributable to genetics alone. >Inheritance

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.

Sexual Differentiation

In the mother's womb, the male fetus is exposed to testosterone (because of the Y chromosome) which leads to the development of male genitalia. If low levels of testosterone are released in the uterus, the result is female.

Environment

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

Culture and Child Rearing

Individualist cultures (European) raise their children as independent individuals whereas collectivist cultures (Asian) raise their children as interdependent.

Human Sexuality

Males and females, to a large extent, behave and think similarly. Differences in sexes arise in regards to reproductive behaviors. In the U.S. Questions such as casual sex, sex for affection, and thoughts about sex happens.

Mating Preferences

Males look for youthful appearing females in order to pass their genes into the future. Females, on the other hand, look for maturity, dominance, affluence and boldness in males. Men are typically more attracted to a woman whose waists are roughly a third narrower than their hips - a sign of future fertility. Men are attracted to women who are at the age of peak fertility (which has shifted over time). Women are more attracted to men who seem more mature, dominant, bold and affluent.

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 US, the male-to-female arrest ratio for murder is 10:1. However, this data set may be flawed because females are discouraged to act on anger but in reality some cases women can be more aggressive when they express.

Natural Selection and Mating Preferences

Natural selection has caused males to send their genes into the future by mating with multiple females since males have lower costs involved However, females select one mature and caring male because of the higher costs involved with pregnancy and nursing.

Evolutionary Successes that Explain Difference

No more than 5% of the genetic differences among humans arise from population group differences. Therefore, 95% of genetic variation exists within populations. The typical genetic difference between two Icelandic villagers or between two Kenyans is much greater than the average difference between to the two groups.

Gender Roles

Our culture shapes our gender roles — expectations of how men and women are supposed to behave.

Effects of Parenting

Parental influence is largely genetic. This support is essential in nurturing children. However, other socializing factors also play an important role

Parenting

Parenting does have an effect on biologically related and unrelated children. - Attitudes - Values - Manners - Beliefs - Faith - Politics

Social Learning Theory

Proposes that we learn gender behavior like any other behavior—reinforcement, punishment, and observation.

Inheritance

The information in our genes that is passed to us through our parents through our chromosome

Genome

The set of complete instructions for making an organism, containing all the genes in that organism. Thus, the human genome makes us human, and the genome for drosophila makes it a common house fly

Parents and Early Experiences

What about the environment? How do our early experiences, our family, our community and our culture affects these differences? "We are not blank slates" but rather coloring books, with certain lines predisposed and experience filling in the picture (Douglas Kenrick)

Gender Differences and Connectedness

Young and old, women form more connections (friendships) with people than do men. Men emphasize freedom and self-reliance. > nature and nurture are speculated in this