Nature, Nature, and
Human Diversity
Evolutionary Psychology
Genes “Our Codes For Life”
• Each person contains 46 chromosomes – 23 by your mother, 23 by your
father
• Chromosome: threadlike structures made of DNA molecules that contain the genes
• Genes are the biochemical units of heredity that make up the chromosomes
– a segment of ones DNA
• DNA (deoxyribonucleic acid) – a complex molecule containing the genetic
information that makes up the chromosomes
Genetics and Twins
• Identical twins: twins who develop from a single fertilized egg that splits into
two, creating two genetically identical organisms
• Fraternal twins: twins who develop from a single fertilized egg. They share a
fetal environment but are not genetically any closer than brother and sister
Identical Twins
Fraternal Twins
Biological Versus Adoptive Relatives
• Genetic relatives (biological parents and siblings) and environmental relatives
(adoptive parents and siblings)
• Question: Are adopted children more like their biological parents, who
contributed their genes, or their adoptive parents, who contribute a home
environment?
• Answer: The environment shared by a family’s children has no impact on
their personalities – people who grow up together, whether biologically
related or not do not much resemble one another in personality.
Temperament
• Temperament: a person’s characteristic emotional reactivity and intensity
• Temperament levels may stay with you your entire life
Gene-Environment Interaction
• Genes and experience interact with each other – the effect on one factor
(such as the environment) depends on another factor (such as heredity)
• Example: Imagine two babies, one genetically predisposed to be attractive, sociable, and
easygoing, the other less so. Assume further that the first baby attracts more
affectionate and stimulating care than the second and so develops into a warmer and
more outgoing person. As the two children grow older, the more naturally outgoing
child more often seeks activities and friends that encourage further social confidence.
Evolutionary Psychology
• Evolutionary Psychologists: focus mostly on what makes us so much alike as
humans
• They use natural selections or 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.
• Due to natural selection, organisms can adapt to changing environments
• A mutation is a random error in the replication of genes
Evolutionary Explanation of Human Sexuality
• Whether male or female, we eat the same foods, avoid the same predators, and perceive, learn, and remember
similarly. Reproduction, however, is where the genders may differ, according to evolutionary psychology.
• Who desires more frequent sex, thinks more about sex, masterbates more often, initiates more sex, and sacrifices
more to gain sex?
• Men
• In a survey of 289,000 college students, 58 percent of men but only 34 percent of women agreed that “if two
people really like each other, it’s all right for them to have sex even if they’ve known each other for a very short
time.”
• In another survey, 48 percent of women but only 25 percent of men citied affection as a reason for first intercourse.
• 54 percent of men say they think about sex everyday as opposed to 19 percent of women
• In another survey gay men are more likely to have uncommitted sex than lesbian women
Mating Preferences
• Studies have shown that men are more attracted to women who have a
youthful appearance, and are healthy. Evolutionary psychologists attribute
this to the fact these qualities suggest many childbearing years.
• Studies have shown that women are more attracted to men who seem
mature, dominant, bold, and have potential for a long term relationship with
interests in having children.
How Much Credit (Or Blame) Do Our Parents
Deserve?
• How we are raised (environmental) can effect how we behave. (temperament)
• For instance, children who are abused growing up are more likely to become
abusive later in life, those who are neglected become the neglectful, the
loved-children can become self-confident and socially competent.
• Immigrants and academic focused families are more likely to have children
who succeed in school.
• However, one factor cannot be attributed to parents…..
Peer Influence
• At all ages, especially during childhood and adolescence, we seek to fit into
groups and are subject to group influences
• Preschoolers who disdain a certain food often will eat that food if put on a
table with a group of children who like it
• Children who speak English with a certain accent at home are more likely to
lose that accent when around peers who speak differently.
• Teens who smart smoking, typically have friends that do
Cultural Influences
• Behaviors can also be attributed to culture…
• The enduring behaviors, ideas, attitudes, values, and traditions shared by a group of
people and transmitted from one generation to the next
• What are some cultural behaviors you can think of ?
• Each culture has its norms – or socially accepted behaviors
Individualism vs. Collectivism
• 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 goals of one’s group (often one’s extended
family or work group) and defining one’s identity accordingly.
• Have you ever behaved differently in a group versus how you normally
behave?
Gender Similarities and Differences
• Among your 46 chromosome, 45 are unisex – however there are differences between men
and women
• 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 can become sexually rearoused immediately after orgasm, they can smell
fainter odors, express emotions more freely, and are offered help more often. They are
doubly vulnerable to depression and anxiety, 10 times more likely to develop an eating
disorder
• Compared with the average woman, the average man is 4 times more likely to commit
suicide or suffer alcohol dependence, more likely to become diagnosed with autism, colorblindness, ADHD, and antisocial personality disorders.
Gender Differences
• The differences can be attributed to social perception
• Men are perceived as more aggressive, whereas women are perceived as more nurturing
• In childhood, boys typically play in larger groups and are more competitive whereas
girls are in smaller groups and care more about social relationships
• Females are more interdependent than males, meaning they spend less time alone and
want to be around social interactions
• Can you think of any more?
The Nature of Gender
• Males and females are variations of the same form. Seven weeks after
conception, you were anatomically indistinguishable from someone of the
other sex. Then your genes activated your biological sex, which was
determined by your 23rd pair of chromosomes.
• From your mother you received an X chromosome.
• From your father you received an X chromosome making you a girl or a Y
chromosome making you a boy.
• The Y chromosome is found only in males.
Gender Roles
•
•
•
•
Gender role: a set of expected behaviors for males or for females
Gender identity: our sense of being male or female
Gender typing: the acquisition of a traditional masculine or feminine role
Social learning theory: the theory that we learn social behavior by observing
and imitating and by being rewarded or punished
• Children learn their social behaviors and gender roles first through their parents