Introduction to Psychology

1
Myers EXPLORING PSYCHOLOGY (7th Ed)
Chapter 3 The Nature and Nurture of
Behavior James A. McCubbin, PhD Clemson
University Worth Publishers
2
Genes Our Biological Blueprint

• Chromosomes
• threadlike structures made of DNA molecules that
  contain the genes
• DNA (deoxyribonucleic acid)
• a complex molecule containing the genetic
  information that makes up the chromosomes
• has two strands-forming a double helix- held
  together by bonds between pairs of nucleotides

3
Genes Our Biological Blueprint

• Genes
• the biochemical units of heredity that make up
  the chromosomes
• a segment of DNA capable of synthesizing a
  protein
• Genome
• the complete instructions for making an organism
• consisting of all the genetic material in its
  chromosomes

4
Genetics and Behavior
5
Evolutionary Psychology

• Natural Selection
• the principle that, among the range of inherited
  trait variations, those contributing to
  reproduction and survival will most likely be
  passed on to succeeding generations
• Mutation
• a random error in gene replication that leads to
  a change in the sequence of nucleotides
• the source of all genetic diversity

6
Evolutionary Psychology

• Evolutionary Psychology
• study of the evolution of behavior using the
  principle of natural selection, which presumably
  favors genes that predispose behavior tendencies
  and information--processing systems that solved
  adaptive problems faced by our ancestors
• Gender (in psychology)
• the characteristics, whether biologically or
  socially influenced, by which people define male
  and female

7
Behavior Genetics

• Identical Twins
• develop from a single fertilized egg that splits
  in two, creating two genetically identical
  organisms and share the same placenta
• Fraternal Twins
• develop from separate eggs
• genetically no closer than brothers and sisters,
  but they share a fetal environment

8
Behavior Genetics

• Behavior Genetics
• study of the power and limits of genetic and
  environmental influences on behavior
• Environment
• every nongenetic influence, from prenatal
  nutrition to the people and things around us

9
Behavior Genetics

• Temperament
• a persons characteristic emotional reactivity
  and intensity (Identical twins are likely to show
  the greatest similarity in temperament.)
• Interaction
• the effect of one factor (such as environment)
  depends on another factor (such as heredity)
• Molecular Genetics
• subfield of biology that studies the molecular
  structure and function of genes and assesses
  possible linkages between specific nucleotide
  sequences and disorders

10
Environmental Influence
11
Environmental Influence

• Rats reared in an environment enriched with
  playthings show increased development of the
  cerebral cortex

12
Environmental Influence

• A trained brain

13
Environmental Influence

• Culture
• the enduring behaviors, ideas, attitudes, and
  traditions shared by a large group of people and
  transmitted from one generation to the next
• the mark of our species is our ability to learn
  and adapt
• Norm
• an understood rule to accepted and expected
  behavior
• norms prescribe proper behavior of cultures

14
Gender

• X-Chromosome
• sex chromosome found in both men and women
• females have two, males have one
• an X-chromosome from each parent produces a
  female
• Y-Chromosome
• sex chromosome found only in males
• when paired with an X sex chromosome from the
  mother, it produces a male child

15
Gender

• Testosterone
• most important of the male sex hormones
• both males and females have it
• additional testosterone in males
• stimulates growth of male sex organs in the fetus
• stimulates development of male sex
  characteristics during puberty

16
Gender

• Role
• a set of expectations about a social position,
  defining how those in the position ought to
  behave
• Gender Role
• a set of expected behaviors for males and females

17
Gender Role

• Example male
• initiate sexual activity.
• express permissive attitudes regarding casual
  sex.
• think frequently about sex.
• Example female
• Stay home and take care of children

18
Gender

• Gender Identity
• ones sense of being male or female
• Gender-Typing
• the acquisition of a traditional masculine or
  feminine role

19
Gender

• Percentage agreeing The activities of married
  women are best confined to home and family

20
Gender

• Social Learning Theory
• we learn social behavior by observing and
  imitating and by being rewarded or punished
• Gender Schema Theory
• children learn from their cultures a concept of
  what it means to be male and female
• adjust behavior accordingly

21
Gender

• Role
• a set of expectations (norms) about a social
  position, defining how those in the position
  ought to behave
• Gender Role
• a set of expected behaviors for males and females

22
Gender

• Two theories of gender-typing

Social learning theory
Gender schema theory
Rewards and punishments Observation
and imitation of models
Cultural learning of gender
Gender schema (looking at self and world through
a gender lens)
Gender-organized thinking Gender-typed behavior
Gender-typed behavior