Module 9: Environmental Influences on Behavior

1. Module 9: Environmental Influences on Behavior

2. Experience and Early Brain Development • Our genes dictate our overall brain architecture, but experience fills in the details, developing neural connections and preparing our for thought, language, and other later experiences. • Early postnatal experiences affect brain development. Rosenzweig et al. (1984) showed that rats raised in enriched environments developed thicker cerebral cortices than those in an impoverished environment. • After 60 days in an enriched environment a rats' brain weight increased by 7 to 10 percent and the number of synapses mushroomed by about 20 percent.

3. Experience and Early Brain Development

4. Experience and Early Brain Development • After brain maturation provides us with an abundance of neural connections, our experiences trigger a pruning process. Unused neural pathways weaken and degenerate. • The brain is naturally “experience expectant.” During childhood, while excess connections are still available, youngsters can most easily master such skills as the grammar and accent of a second language. Lacking any exposure to language before adolescence a person will never master any language.

5. How Much Credit (or Blame) Do Parents Deserve • Parenting matters... • The power of parenting to shape our differences is clearest at the extremes- the abused who become abusive, the neglected who become neglectful, the loved but firmly handled children who become self confident and socially competent. • The power of the family environment frequently shows up in children's political attitudes, religious beliefs, and personal manners as well.

6. How Much Credit (or Blame) Do Parents Deserve • In personality measures, the shared environment – including the home influences siblings share – typically account for less than 10 percent of children's differences. • “Two children in the same family are on average as different from one and other as are pairs of children selected randomly from the population.

7. How Much Credit (or Blame) Do Parents Deserve • Parents should be given less credit for kids who turn out great and blamed less for kids who don't. • Knowing children are not easily sculpted by parental nurture, parents can relax a bit more and love their children for who they are.

8. Peer Influence • At all ages, but especially during childhood and adolescence, we seek to fit in with groups and are subject to group influence. – Preschoolers who disdain a certain food will eat that food if put at a table with a group of children who like it. – Children who hear English spoken with one accent at home and another in the neighborhood and at school will invariably adopt the accent of their peers, not that of their parents. – Teens who start smoking usually have friends who model smoking. However, part of this influence may be a result of a selection effect- those who smoke (or don't) may select as friends those who smoke (or don't).

9. Peer Influence

10. Peer Influence V.S. Parent Influence • Howard Gardner points out that parents can influence the culture that shapes peer groups by helping to select their children's neighborhoods and schools. • If a toxic climate is seeping into a child's life, that climate – not just the child – needs reforming. • Peers are an important social influence but they are not the only one. • Parents tend to influence their children's personal values and morality. Peers tend to influence someone's appearance / image.

11. Cultural Influence • Culture- The behavior, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next. • Other primates exhibit the rudiments of culture with local customs of tool use, grooming, and courtship. Younger chimpanzees and macque monkeys sometimes invent local customs (potato washing, in one example) and pass them on to their peers and offspring.

12. Cultural Influence • Thanks to our mastery of language, humans enjoy the preservation of innovation, which allows cultural and technological change to accumulate. • Culture provide the shared and transmitted customs and beliefs that enable us to communicate, to exchange money for things, to play, to eat, and drive with agreed upon rules.

13. Variations Across Cultures • Each cultural group evolves its own norms – rules for accepted and expected behaviors • Visiting Europe, North Americans notice smaller cars, the left-handed use of forks, the uninhibited attire on beaches. Stationed in Iraq, Afghanistan, and Kuwait, American and European soldiers alike realize how liberal their home cultures are. • If someone invades our personal space – the portable buffer zone we like to maintain around our bodies – we feel uncomfortable.

14. Variations Across Cultures • Cultures also vary in their expressiveness. Those with roots in northern European culture have perceived people from Mediterranean cultures as warm and charming but inefficient. • The Mediterraneans, in turn, have seen Northern Europeans as efficient but cold and preoccupied with punctuality. • Cultures vary in their pace of life too. People from time-conscious Japan – where bank clocks keep exact time, pedestrians walk briskly, and postal clerks fill requests speedily – may find themselves impatient when visiting Indonesia where clocks keep less accurate time and the pace of life is more leisurely.

15. Variation Over Time • Cultures can change rapidly over time. • For example, with greater economic independence, today's women are more likely to marry for love and less likely to endure abusive relationships out of economic need. • American culture has changed rapidly from 1960 to today. In present times there is more divorce, delinquency, and depression than there was 50 years ago.

16. Culture and the Self • Cultures vary in the extent to which they give priority to the nurturing and expression of personal identity or group identity. • Individualism- Giving priority to one's own goals over group goals and defining one's identity in terms of personal attributes rather than group identifications. • Collectivism- Giving priority to the group's goals (often those of the extended family or work group) and defining one's identity accordingly.

17. Culture and Self • Individualists share the human need to belong. They join groups but they are less focused on group harmony and doing their duty to the group. • Being more self contained, they more easily move in and out of groups, feeling free to switch places of worship, leave one job for another, or even leave their extended families and migrate to a new place. • Collectivists value preserving group spirit and making sure others never lose face. What people say not only reflects what they feel but what they presume others feel. Elders and superiors receive respect and duty to family members may trump personal career preferences.

18. Culture and Self • Individualism's benefits can come at the cost of more loneliness, divorce, homicide, and stress-related disease. Demands for romance and personal fulfillment in marriage can subject relationships to more pressure. • In one survey, “keeping romance alive” was rated as important to a good marriage by 78 percent of US women but only 29 percent of Japanese women. • In China, love songs often express enduring commitment and friendship.

19. Culture and Self

20. Culture and Child-Rearing • Child rearing practices reflect cultural values that vary across time and place. • Do you prefer children who are independent or children who comply? • Western cultures say, “You are responsible for yourself. Follow you conscience. Be true to yourself. Discover your gifts. Think through your personal needs.” • Eastern cultures say, “Be true to you traditions. Be loyal to your heritage and country. Show respect toward your parents and other superiors.”

21. Culture and Child-Rearing • Many Asians and Africans live in cultures that value emotional closeness. • Rather than being given their own bedrooms and entrusted to day care, infants and toddlers may sleep with their mothers and spend their days close to a family member. • These cultures encourage a strong sense of family self – a feeling of what shames the child shames the family, and what brings honor to the family brings honor to the self.

22. Developmental Similarities Across Groups • One 49 country study revealed that nation to nation differences in personality traits such as conscientiousness and extraversion are smaller than most people propose. • Even differences within a culture, such as those sometimes attributed to race, are often easily explained by an interaction between our biology and culture. • Higher blood pressure in African American populations may be the result of greater sodium intake rather than a direct biological predisposition.

23. Gender Development • Our biological sex helps define our gender, the biological and social characteristics by which people define male or female. • Nurture and nature interact together to create our differences in gender.

24. Gender Similarities and Differences • Men and women are in most ways alike, sharing the same set of genes, except for the last 23rd pair of chromosomes. • Compared with the average man, the average woman enters puberty two years sooner, lives five years longer, carries 70 percent more fat, has 40 percent less muscle, and is 5 inches shorter. • Women are doubly vulnerable to depression and anxiety, and their risk of developing an eating disorder is 10 time greater. • Men are four times more likely to commit suicide or suffer alcohol dependence. They are far more diagnosed with autism, color blindness, attention deficit hyperactivity disorder as adults.

25. Gender and Aggression • Men admit to more aggression than women do and experiments confirm that men tend to behave more aggressively, such as by administering what they believe are more painful electric shocks. • However, this aggression gender gap pertains to physical aggression rather than relational aggression. • The gender gap in physical aggression appears in everyday life at various ages and in various cultures, especially those with greater gender inequality. • The male to female arrest ration for murder, for example, is 10 to 1 in the United States and almost 7 to 1 in Canada.

26. Gender and Social Power • People worldwide perceive men as more dominant, forceful, and independent while women are more deferential, nurturing, and affirmative. • When groups form, whether as juries or companies, leadership tends to go to males. • As leaders, men tend to be more directive, even autocratic; women tend to be more democratic, more welcoming of subordinates participation in decision making. • These differences carry into everyday behavior, where men are more likely to act as powerful people often do- talking assertively, interrupting, initiating touches, starting more, and smiling less.

27. Gender and Social Connectedness • According to C. Gilligan, the “normal” struggle to create a separate identity describes Western individualist males more than relationship oriented females. • These gender differences in connectedness surface early in children's play and they continue with age. Boys typically play in large groups with an activity focus and little intimate discussion. Girls usually play in smaller groups, often with one friend.

28. The Nature of Gender • X Chromosome- Sex chromosome found in both men and women • Y Chromosome- The Sex chromosome found only in men. • Testosterone- The most important of the male sex hormones. Both males and females have it, but additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics.

29. The Nature of Gender • Between the 4th and 5th month of prenatal development, sex hormones bathe the fetal brain and influence its wiring. Different patterns for males and females develop under the influence of the males greater testosterone and the females ovarian hormones. • In adulthood parts of the frontal lobes, the area involved in verbal fluency, are reportedly thicker in women. Part of the parietal cortex, a key area for space perception, is thicker in men. Gender differences also appear in the hippocampus, the amygdala, and the volume of brain gray matter (the neural bodies) versus white matter (the axons and dendrites). • A study of 14 boys born without normal male genitals but still genetically male and raised as girls found that 6 later declared themselves male, 5 were living as female, and 3 had an unclear sexual identity.

30. The Nurture of Gender • Gender Roles- A set of expected behaviors for males or females. • Compared with employed women, employed men in the United States spend about an hour and a half more on the job each day and about an hour less on household activities and caregiving. • Gender roles can smooth social relations, saving awkward decisions about who does the laundry each week and who mows the lawn. But they often do so at a cost. If we deviate from such conventions, we may feel anxious.

31. The Nurture of Gender • Do gender roles reflect what is biologically natural for men and women, or do cultures construct them? Gender role diversity over time and space indicates that culture has a big influence. • Nomadic societies of food gathering people have only a minimal division of labor by sex. Boys and girls receive much the same upbringing. • In Agricultural societies, where women work in the fields close to home and men roam more freely herding livestock, children typically socialize into more distinct gender roles.

32. Gender and Child Rearing • Gender Identity- Our sense of being male or female. • Gender Typed- The acquisition of traditional masculine or feminine role. • Social Learning Theory- The theory that was learn social behavior by observing and imitating and by being rewarded or punished. • SLT assumes that children learn gender linked linked behaviors by observing and imitating by being rewarded or punished. “Nicole, your such a good mommy to your dolls” ; “Big boys don't cry, Alex”.

33. Gender and Child Rearing • Even when families discourage gender typing, children usually organize themselves into “boy worlds” and “girl worlds” each guided by rules for what boys and girls do. • Cognition also matters- Children form schemas, or concepts that help them make sense of the world. One of these schemas is for gender. A gender schema can then be a lens through which children view their experiences. • Before age 1 children begin to discriminate male from female voices. After age 2 language forces children to begin organizing their world on the basis of gender. English, for example, uses the pronouns he and she; other languages classify objects as masculine (le train) or femine (la table).