Behavior Genetics and Evolutionary Psychology

1
Behavior Genetics and Evolutionary Psychology

• Module 8
• PSY101

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
Genetics and Behavior
23 chromosomes a gift from moms egg 23
chromosomes a gift from dads sperm
4
Chromosome Problems

• Female xx sex chromosomes
• Male xy sex chromosomes
• At least one x chromosome is essential for life.
  A single y is never enough for development.

5
Chromosome Problems

• Some abnormal sex chromosome patterns
• Turners syndrome xo
• http//en.wikipedia.org/wiki/Turner_syndrome
• Kleinfelters syndrome xxy
• http//genetics.emedtv.com/klinefelter-syndrome/kl
  inefelter-syndrome-symptoms.htm
• l
• Double Y syndrome xyy
• http//en.wikipedia.org/wiki/XYY_syndrome
• Fragile-X syndrome xy (x is
  thin,fragile)
• http//www.ncbi.nlm.nih.gov/pubmedhealth/PMH000263
  3/

6
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

7
Human Genome Project,Findings

• Humans are 99.95 identical
• Many human genes appear only in humans and appear
  to have come from bacteria.
• One gene makes 2 or 3 proteins, complex chains of
  amino acids that carry out the tasks of life.
• Every humans genome shows the residues of
  evolution.

8
Dominant and Recessive Genes

• http//www.blinn.edu/socialscience/ldthomas/feldma
  n/handouts/0203hand.htm
• A dominant trait does not mean "more potent" and
  recessive does not mean "weaker."
• The terms refer to the visible trait.

9
Genes Our Biological Blueprint

• Is there a difference between female and male
  brains?
• What do you think?
• What do we know?

10
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
• Note See handout 8-3

11
How Evolutionary Psychology Works

• Many years of drought
• Finches evolved thicker beaks
• Enabled them to crack harder seeds
• Over many years of heavy rains
• Finches developed thinner beaks
• Enabled them to eat softer seeds

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E.P. , Children and Bedtime

• Why do young children resist going to bed?
• We say they are spoiled.
• Is it true?
• In hunter-gatherer days, being alone in the dark
  was dangerous, monsters were real.
• Present day hunter-gathers consider allowing a
  child to sleep alone to be child abuse.

13
Timothy Miller Practical Implications of E.P.

• Humans strive for the prerequisites of
  reproductive success
• Wealth
• Status
• Love
• From an evolutionary perspective there is no such
  thing as enough reproductive success.

14
Genetic Effects on Taste

• The ability to taste Phenylthiocarbamide (PTC)
• Is an inherited trait.
• About 2/3 of Americans are tasters.
• Determined by one pair of alleles, T and t
• Ability to taste is dominant.

15
Genetics and EvolutionQuestions

1. Would you want to take a test telling you what
   diseases you may develop?
2. Would you want your unborn child tested for
   genetic defects?
3. Should employers use genetic tests when hiring?

16
Evolutionary Psychology

• Gender (in psychology)
• the characteristics, whether biologically or
  socially influenced, by which people define male
  and female
• What do we look for in mates?
• Note handout 8-4

17
Evolutionary Psychology
Countries with dots were surveyed as to their
mating preferences, in all 10,047 people in 37
countries were asked. Men preferred attractive
features, youth, and health Women preferred
wealth, maturity, social status, health,
attractive
18
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

19

• Take the Sexual Attitudes Scale, 8-5.
• What are your attitudes about sex?

20
Evolutionary Psychology

• Four dimensions of sexuality on the
• Hendrick Sexual Attitude Scale
• 1. permissiveness (items 1-21)
• open, casual sexuality
• sexual practices (items 22-28)
• responsible, tolerant sexuality
• communion in the relationship (items 29-37)
  emotional, idealistic sexuality
• 4. instrumentality (items 38-42)
• sex as egocentric and very biological

21
Evolutionary Psychology

• The Hendrick Sexual Attitude Scale
• (Handout 8-5)
• Some findings about sex
• Men identify a more casual, less conventional,
  and more manipulative approach.
• Women are into love/sexuality practical and
  conventional approach.
• Very religious people differed from most others
  responses.
• Those who had been in love several times were
  more endorsing of permissiveness and some
  instrumentality.
• Those currently in love were less permissive and
  instrumental and more endorsing of communion.

22
Just for Fun

• http//www.youtube.com/watch?vVqiw-Kqtlr0

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Critiques of Evolutionary Psychology

• If men are committed to their mates, only those
  genes survived.
• If men are only interested in protecting their
  gene pool they would stay with the woman carrying
  their children.
• This evolutionary speculation reinforces
  male-female stereotypes.
• We can be socialized to be monogamous or
  polygamous.
• Could be a result of acculturation into family
  and community structure.

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Behavior Genetics

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

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Prenatal Environmental Differences

• Separate placentas and blood sources (all
  fraternal)
• b. Share the same placental blood.
• Separate placenta twins are somewhat less
  similar. Why?

26
Behavior Genetics

• As you know striking similarities have sometimes
  been found between twins who are reunited after
  years of separation. What does this mean?

Try handout 8 - 1, and be Ready to share
your results.