Chapter 3: Nature, Nurture, and Human Diversity - PowerPoint PPT Presentation


PPT – Chapter 3: Nature, Nurture, and Human Diversity PowerPoint presentation | free to download - id: 71f0d5-MTQ1M


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation

Chapter 3: Nature, Nurture, and Human Diversity


Chapter 3: Nature, Nurture, and Human Diversity – PowerPoint PPT presentation

Number of Views:255
Avg rating:3.0/5.0
Slides: 27
Provided by: E2007158
Learn more at:


Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Chapter 3: Nature, Nurture, and Human Diversity

Chapter 3 Nature, Nurture, and Human Diversity
Nature vs. Nurture
  • While we often focus on human diversity, it is
    important to remember that all people are part of
    the human family we not only share the same
    basic biological make up, but common behavioral
    tendencies throughout the world, people form
    groups, laugh and cry, sing and dance, play
    sports and games, etc.
  • In order to determine why there is such diversity
    within these behaviors, scientists revert back to
    the biggest debate in psychology nature vs.
    nurture (genes vs. environment)

Behavior Genetics
  • Behavior geneticists study differences and
    weigh the relative effects of heredity and
  • At a biological level, genes guide us through our
    daily lives. Genes are small segments of DNA
    molecules, which combine to form chromosomes.
    Normal humans have 46 chromosomes 23 are given
    in the mothers egg and 23 are given in the
    fathers sperm.
  • Genes do not directly guide our behavior, but
    they do serve as the building blocks of our
    physical development. A genome is an organisms
    genetic profile the complete set of
    instructions for making that organism, consisting
    of all the genetic material and its chromosomes.

  • Genetically speaking, every human is close to
    being an identical twin on average, we share
    99.9 of our DNA makeup.
  • Variations in DNA that in their many combinations
    define each persons uniqueness. Slight
    variations can give clues to why one person has a
    disease that another does not, why one person is
    short and another tall, why one is happy and
    another depressed.
  • It is important to note that all human traits
    (physical and mental) are influenced by many
    genes acting together.

Twin Studies
  • One of the best ways to try to conquer the nature
    vs. nurture debate is through twin studies. In
    order to conduct twin studies, we must first
    differentiate between the 2 types of twins that
  • 1. Identical Twins developed from a single,
    fertilized egg that split in two these twins
    are genetically identical they are natures
    clones they even share the same conception,
    uterus, birth date, etc.
  • 2. Fraternal Twins developed from separate
    fertilized eggs genetically, they are no more
    similar than ordinary brothers and/or sisters.
  • Countless studies have been devoted to the
    behavior of identical vs. fraternal twins in
    most cases, results have shown that identical
    twins genealogy does often account for
    behavioral similarities.
  • Be careful with common conclusions.
  • SEE Separated Twin Studies (pg. 99-100)

Adoption Studies
  • These studies are interesting because they
    compare behavior traits of the kids to their
    biological parents and siblings and to their
    adoptive parents and siblings.
  • If behavior is more like their biological /
    adoptive family? It must be
  • Findings have shown that adopted children tend
    to resemble their biological parents in their
    personality (patterns of thinking, feeling, and
    acting), but they resemble their adoptive parents
    in their values, attitudes, mannerisms, faith,
    and politics.
  • How many of you have brothers or sisters that are
    total opposites of you?
  • Why do you think this is the case?

Temperament Studies
  • One of the easiest ways to compare people is
    through their temperament a persons emotional
    reactivity and intensity.
  • Temperament can be seen soon after birth and
    often carries on (unchanged) throughout
  • If temperament stays the same throughout ones
    lifetime, which side of the big debate seems to
    get stronger?

  • Scientists can use the data that they collect
    from these experiments to estimate a traits
    heritability the extent to which variation
    among individuals can be attributed to their
    differing genes.
  • Heritability tries to explain differences that
    exist between people (especially when
    environments are similar). It does not try to
    say why certain groups act as they do or why they
    have changed over time.
  • Genes are self-regulating, they do not plan our
    future for us, they simply react to environmental
    factors that we encounter throughout our lives.
  • We must remember that our behaviors occur as a
    result of the combination of genes and the

Evolutionary Psychology
  • Evolutionary psychologists focus mostly on what
    makes us so much alike as humans the bulk of
    their work revolves around the theory of natural
    selection the principle that inheritable traits
    that best promote reproduction/survival will most
    likely be passed from parents to offspring.
    Animal examples
  • Our adaptive flexibility in responding to
    different environments contributes to our fitness
    our ability to survive and reproduce.
  • Natural selection is the key to explaining why we
    as humans are so much alike. Evolutionary
    psychologists point to the fact that most people
    like sweet and/or fatty foods this is because
    these types of food helped our ancient ancestors
    survive famines.

Parents and Peers
  • So far, we have seen how genes can influence our
    individual development, but we have yet to look
    at the role of nurture. Nurture itself begins at
    conception and extends to our families and
    friends throughout our lives.
  • In the womb, nurture entails the level of
    nutrition that an embryo receives from the
    mother. Once born, our experiences foster brain
    development experiments with rats found that
    those living in an enriched environment usually
    develop heavier and thicker brain cortexes than
    rats that lived in impoverished environments.
    Touch also has a profound effect on development.
  • Example NICUs

  • The brain is born with an abundance of neural
    connections waiting to be used experience
    strengthens these connections, while unused
    connections degenerate.
  • For us to have optimum brain development, normal
    stimulation during the early years is critical.
  • Examples Foreign Languages
  • The maturing brain seems governed by a rule Use
    it or lose it.

Parental Influence
  • Parents face a lot of pressure when it comes to
    their children. While not everything can be
    attributed to them, parents definitely matter.
    Parenting can shape our differences in
    aggression, neglect, self-confidence, social
    competency. Often times our family environment
    shapes our political views, religious beliefs,
    and personal manners as well.
  • See Twin Study on pg. 114-115
  • It is important to note that while parents
    obviously affect our differences, the effect can
    often be overstated. In the end, all parents are
    going to do things differently (and with
    different results) the key is that the parents
    are there in the first place loving, teaching,
    and supporting.

Peer Influence
  • At all ages, we seek to establish ourselves and
    to be accepted this has a significant influence
    on day-to-day behavior. Kids typically seek out
    peers with similar attitudes and interests (good
    or bad) this method is referred to as the
    selection effect.
  •  Peer influence has 2 positive results for
  • 1. If parents dont affect their kids as much as
    we thought, then its safe to believe that their
    friends wont affect them as much as we think
  • 2. If a kid turns out bad, they can just blame it
    on their kids friends )

Cultural Influences
  • Culture a set of enduring behaviors, ideas,
    attitudes, values, and traditions shared by a
    group of people and transmitted from one
    generation to the next. Culture supports
    survival and reproduction with its social and
    economic systems.
  • What are some ideologies, symbols, etc. of
    American culture?
  • The one common thread of all cultures is the
    existence of culture itself. Groups of people
    living everywhere in the world have created,
    followed, and passed on culture.

Variations Across Cultures
  • Each cultural group evolves its own norms the
    rules for accepted and expected behavior. These
    norms are important because they take
    planning/worrying out of everyday life by
    knowing cultural traits, we can relax and carry
    on with our lives without fear or embarrassment
    or insult.
  • What happens when norms collide?
  • Personal space
  • When different cultures interact, two of the
    greatest cultural shocks for people are often
    pace of life and sense of punctuality (other than
    the biggies like language, dress, food, etc.).

  • Keep in mind that cultures change over time
    consider the U.S. since 1960.
  • ()s greater economic independence, human
    rights, and the Internet.
  • ()s doubled divorce rates, quadrupled juvenile
    violent crime, and quintupled prison population.
  • No matter what the variation (good or bad), that
    our culture is constantly shaping our lives.

Culture and the Self
  • Cultures vary in the event to which they give
    priority to the nurturing and expression of ones
    personal identity or of ones group identity.
    Cultures tend to lean toward one of the following
  • 1. Individualism giving priority to ones own
    goals over group goals and defining ones
    identity in terms of personal attributes rather
    than group identifications ME.
  • 2. Collectivism giving priority to the goals
    of ones group (often ones extended family or
    work group) and defining ones identity
    accordingly WE.
  • Individualists are typically more independent,
    express their uniqueness, care about themselves,
    have many casual relationships, and act in ways
    that best suit their personality/attitudes.
  • Collectivists are typically more interdependent,
    try to fit in, care about the group, have
    enduring relationships, and act in ways that
    reflect social norms/roles.

  •  Interestingly, individualist cultures face the
    extremes when it comes to overall satisfaction of
    life people in these cultures report greater
    happiness and greater sadness as well.
  • The cultural traits of individualism and
    collectivism are taught during the child-rearing
    process kids in the U.S. are taught to be
    independent, while many Eastern and African
    cultures are brought up learning family self a
    feeling that what shames the child shames the
    family (or what brings honor to the child brings
    honor to the family).
  • We must remember that regardless of particular
    culture, all humans share the same life cycle.
    As members of one species, we seem subject to the
    same psychological forces.

Gender Development
  • Among the easiest ways to categorize people is by
    gender our assumed characteristics as male or
  • Common Gender Similarities and Differences
  • Women have 70 more fat than men, 40 less
    muscle, are 5 shorter, will live 5 more years,
    are better at smelling faint odors, expressing
    emotions, are twice as likely to experience
    depression and/or anxiety, and are 10 times more
    likely to have eating disorders.
  • Men 4 times more likely to suffer alcoholism,
    commit suicide, and are more likely to be
    diagnosed with autism, color-blindness,
    hyperactivity (as children), and antisocial
    personality disorder (as adults).
  • Obviously this list could go on and on, but
    there are 2 major social differences that come to
    the forefront

  • Aggression In surveys, men admit more
    aggression (physical) than women this fact has
    also been supported by scientific experiments.
    Violent crime can help illustrate this point in
    the United States, the male-to-female arrest
    ratio for murder is 9 to 1 (7-1 in Canada).
    Throughout the world, hunting, fighting, and
    warring are primarily mens activities.
  • Social Power All over the world, men are viewed
    as more dominant, forceful, and independent
    while women are seen as more deferential,
    nurturing, and dependent. As leaders, men tend
    to be more directive and autocratic, while women
    tend to be more democratic and welcome of group
    decision making.
  • In everyday behavior, men tend to talk
    assertively, interrupt, initiate touching, smile
    less, and stare these behaviors help perpetuate
    the inequities of social power that exist between
    men and women.

Social Connectedness
  • Women, more than men, are concerned with making
    connections with others. This difference can be
    seen as children play. How does boy and girl
    play typically differ?
  • These differences continue to grow as we move
    throughout life
  • Women As teens, girls spend more time with
    friends and less time alone. As adults, women
    use conversation to explore feelings and
    relationships. They emphasize caring and provide
    most of the care to the very young and the very
    old (69 of people report being close to their
    fathers, while 90 report a close relationship
    with their mothers).
  • Men As teens, boys spend more time in groups.
    As adults, men use conversation to communicate
    solutions and/or state opinions. Men emphasize
    freedom and self-reliance.
  • Men enjoy doing activities side-by-side, while
    women take pleasure in talking face-to-face.
  • These findings are not a big secret the
    ongoing question is Are these differences a
    result of nature or nurture?

The Nature of Gender (Biology)
  • Many gender differences can be explained
    biologically by our differing sex chromosomes and
    concentration of sex hormones.
  • Remember that we are composed of 23 pairs of
    chromosomes (46 total). Sex is determined by the
    23rd pair.
  • Mothers always give the embryo an X chromosome,
    while fathers can give an X or a Y chromosome (Y
  • XX Girl
  • XY Boy
  • YY Impossible

The Nurture of Gender (Environment)
  • Although biologically influenced, gender is also
    socially constructed what biology initiates,
    society accentuates.
  • Culture shapes gender behavior by creating
    expectations to which we should follow called
    roles a cluster of prescribed actions
    behaviors we expect of those who occupy a
    particular social position.
  • One set of norms defines our cultures gender
    roles our expectations about the way that men
    and women should behave. Gender roles can smooth
    social relations interestingly, deviations from
    these roles can make us feel anxious.
  • Examples of gender role deviation in the U.S.?

Gender and Child-Rearing
  • From society, we all gain a feeling of gender
    identity a sense of being male or female. To
    varying extents, we also become gender-typed
    acquiring and displaying traditional masculine or
    feminine roles.
  • How do children learn the correct gender
  • 1. Social Learning Theory kids learn
    gender-linked behaviors by observing and
    imitating based on rewards or punishments.
  • Examples of Reward or Punishment of a Behavior?
  • Observation / Imitation Reward Replicating
    behavior in the future.
  • Observation / Imitation Punishment no
    replication in the future.

  • 2. Gender Schema Theory kids learn from their
    culture a concept of what it means to be male and
    female and that they adjust their behavior
    accordingly (schema a concept that helps us
    organize information).
  • Examples of gender schemas?
  • Through language, dress, toys, and songs,
    children create gender schemas children the
    compare themselves with their concept of gender
    and adjust their behavior accordingly.

Reflections on Nature and Nurture
  • We must always remember that nature and nurture
    have simultaneous effects on us as we move
    throughout life many times, the differences
    initiated by nature are amplified by our nurture.
  • Gender roles are also ever-present, but realize
    that they are converging in todays modern world
    it is not hard to find numerous examples of
    exceptions to most roles.
  • Genes are all-pervasive, but not all powerful.
  • Culture is all-pervasive, but not all-powerful.
  • Nature and nurture push behavior, but our mind
    makes the final decision the mind is