Chapter 3 - The Nature and Nurture of Behavior

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14 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

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1

The Nature and Nurture of
Behavior


Genes


Explaining Similarity


Explaining Differences


Environmental Differences


Gender

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3

4

5

The Human Cell


The human body is comprised of over 200
different kinds of cells which are the smallest self
-
contained structures


Cell membrane:
the outside layer of the cell


Cytoplasm:
is comprised of specialized structures


Mitochondria:
are the powerhouses that process
nutrients and provide the cell’s energy


Endoplasmic reticulum, Golgi apparatus, and
ribosomes:
produce proteins


Neucleus:
The inner part of the cell


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The Nucleus


Chromosomes



Genes



Deoxyribonucleic acid (DNA)

7

Chromosomes


Rod shaped structures found in the center of
the nucleus of every cell in the body.


Each sperm and each ovum contains
23
chromosomes.


The chromosomes contain the genes.


The
fertilized egg (zygote)

and all the body cells
that develop from it (except the sperm cells and
the ova) contain
46 chromosomes.

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Karyotype

A photograph of a cell’s chromosomes
arranged in pairs according to size

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Genes


The basic unit of genetic information


They determine the nature and the function
of the cell.


The human genes (about 140,000) are
referred to as the human
genome.


A genome
is the full set of genes in each
cell of an organism.

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A Portion of a DNA Molecule

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DNA


They determine the nature of each cell
and how it will function.


At each level of the spiral or rungs of the
ladder are particular chemical pairs. The
arrangement of these pairs along the
DNA molecule determines which kind of
proteins that will be formed in the cell.



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Terms


Gametes:

Sex cells (ovum or sperm)



Diploid cells:

Cells having 2 copies of each chromosome




Haploid gametes:

Gametes having 1 copy of each chromosome

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Meiosis


Meiosis takes place in the testicles and ovaries.


A
diploid

cell (having 2 copies of each
chromosome) undergoes a special form of cell
division

to create
haploid
gametes (having 1 copy
of each chromosome).


An egg and a sperm fuse together to form a new
diploid cell called zygote (a process called
fertilization)


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Mitosis


In the first step of mitosis, all chromosomes are
copied
, so that instead of 2 copies, the cell briefly
has
4 copies

of each chromosome.


Shortly afterwards, the cell divides in half,
resulting in two cells each has a complete copy of
the genetic information.


These cells grow larger and eventually undergo
mitosis.


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Gregor Mendel (1800s)


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Genotype

The genetic makeup of a
given individual


Recessive Gene

The gene pair that
determines a trait in an
individual only if the
other member of that
pair is also recessive


Phenotype

The traits that are
expressed in the
individual

Dominant Gene

One gene of a gene pair
that will cause a
particular trait to be
expressed

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Stop and Discuss


Gametes


Zygote


Monozygotic twins


Dizygotic twins


Diploid cells


Haploid gametes


Genome




Chromosomes


Genes


DNA


Meiosis


Mitosis


Phenotype


Genotype




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Celera Genomics Project

The Human Genome Project


In June 26, 2000, they both made an
announcement that the “correct alphabetical
order of the 3.12 billion letters” of the
human genome had been mapped.


It will be many years before the incredibly
complex functions of the genome in making
and maintaining a living human being are
fully understood.

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Genetic Engineering


Alteration of Human Genes


1
-

Gene Therapy



2
-

Germ
-
line Genetic Alterations


Germ
-
line Genetic Intervention



3
-

Genetic Enhancement

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1
-

Gene Therapy


Genetic alteration of somatic cells to treat
disease.


Researchers inject genes that are targeted to
treat a particular disease in to a patient’s
blood stream.


When the genes arrive at the site of the
defective genes, they produce chemicals
that can treat the problem.

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2
-
Germ
-
line Genetic Alteration


Can correct problems for unborn individuals and
future generations.


It targets the genes in the reproductive cells


the egg
and the sperm that combine the DNA to conceive a new
human.


Scientist might detect defective cells soon after
conception, removing them from the mother and
placing them in a test
-
tube culture.


Gene therapy could be employed to correct the defects
in the cells.


The result could be cloning. Parents could some day
customize their children.

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3
-
Genetic Enhancement


Non therapeutic genetic alteration


An attempt to enhance an already healthy
genetic makeup by inserting a gene for
improvement (e.g. height, intelligence, eye
color)

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Cloning


Producing genetic replicas of
the organism

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What Do You Think?

Genetic Engineering

Gene Therapy

Germ
-
Line Genetic

Alterations

Genetic enhancement

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Stop and Discuss


In your opinion, how ethical are these
issues?

1
-

Gene therapy

2
-

Germ
-
line genetic alteration

3
-

Genetic enhancement

4
-

Cloning

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Universal Behaviors

Evolutionary Psychology

Evolution

The process through which species change across
generations

Evolutionary Psychology

The study of inherited psychological
characteristics.

Natural Selection

The traits that contribute to reproduction and
survival will most likely be passed on to
succeeding generations.

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Universal Behaviors

Evolutionary Psychology


Mutation

A random error in gene replication that leads
to a change in the sequence of nucleotides;
the source of all genetic diversity.

Sexuality



31

David Buss

and the International Team

(1994)


50 scientists studied:



10,000 people



in 37 cultures



in 6 continents


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Human Sex Differences Are
Universal


Males


Promiscuous


Undiscriminating


Competitive and
concerned about
dominance


Prefer beauty and
health


Like sexual novelty



Females


Devoted and faithful


Cautious


Less competitive



Prefer resources and
social status


Like stability and
security


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Innate Human Characteristics


Infant Reflexes



An Attraction to Novelty



A Desire to Explore and manipulate objects



An Impulse to play and Fool Around



Basic Arithmetic Skills

34

Language Acquisition Device

Innate Mental Module

Noam Chomsky


Children in different cultures go through
similar stages of linguistic development.


Children combine words in ways adults
never do.


Adults don’t consistently correct their
children’s syntax.


Even retarded children develop language.


Infants can derive simple linguistic rules.

35

Explaining Differences

Behavior Genetics

Behavior Genetics


The study of the relative power and limits
of genetic and environmental influences on
behavior

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Twin Studies


13,000 pairs of Swedish twins, 7000 Finnish
twin pairs, 3810 Australian twin pairs

Identical twins are more similar than fraternal twins
on both extroversion & neuroticism


Battery of questionnaires to 850 U.S. twins

Identical twins are more similar in abilities,
personality traits, & interests.

Reported being treated alike

37

Separated Twins


The Jim Twins


Similar in:



brain waves



voice intonation



interests



heart rate



personality



intelligence

38

Adoption Studies


People who grow up together, whether
biologically related or not, do not much
resemble one another in
personality.


Adoptees’ traits bear more similarities to
their biological parents than to their care
-
giving adoptive parents

39

Temperament Studies

Traits such as


excitability


whether the baby is intense,
reactive, fidgety, easy going, or quiet


tend to remain steady in later years


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Group Differences

Of our genetic differences


Only 6% are among races


Only 8% are differences among groups
within a race


The rest


over 85%
-

are individual
variations within local groups


Some traits are highly heritable:


Weight, height, and intelligence


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The “Obese” Gene


Obese gene causes fat cells to produce
leptin.


Leptin travels through blood to
hypothalamus (regulates appetite)


Leptin reduces appetite


42

The Function of the Protein
Leptin


Reduces appetite



Speeds up metabolism



Makes people more active

43

Why Do People Gain Weight
Rapidly?


Secretion of leptin is impaired



May produce plenty of leptin but
their body does not respond to it.



Tendency to store calories which
have a survival advantage.

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46

47

Gene
-
Environment Interaction

“Heredity deals the cards;
environment plays the hand.”




Psychologist Charles L. Brewer




(1990)



48

Environmental Influence


Prenatal Environment


Experience and Brain Development


Peer Influence


Culture


Gender


49

Prenatal Care


Diet


The father’s involvement


Age of mother


Illness of mother


Drug use


Alcohol


Teratogens


50

Experiences and Brain Development


Rosenzweig and Krech’s experiment on
rats:


Those living in the enriched environment
developed a thicker and heavier brain cortex.


Experience preserves our activated
connections while allowing the unused
connections to degenerate

Use it or lose it

51

Parents and Peers are Complementary

Howard Gardner (1998)


“Parents are more important when it comes to
education, discipline, responsibility, orderliness.
Charitableness, and ways of interacting with
authority figures. Peers are more important for
learning cooperation, for finding the road to
popularity, for inventing styles of interaction
among people of the same age. Youngsters may
find their peers more interesting, but they will
look to their parents when contemplating their
own futures.”

52

Relationships with Peers

1
-

Peers Provide the opportunity to
compare and evaluate opinions, abilities,
and physical changes


a process called
social comparison

2
-

Peers may serve as a
reference groups



groups of people with whom one
compares oneself.

53

Culture


Variation Across Cultures


Variation Over Time


Culture and Child Rearing

54

Gender


The Nature of Gender


X chromosome


Y chromosome


Testosterone


The Nurture of Gender


Gender role

55

What Is the Role of Parenting?

1
-

Do parents really produce future adults with a
wounded child within by being irresponsible?

2
-

Should we blame our parents for our failings?

3
-

Should we shame the parents of troubled
children?

4
-

Should parents be given less credit for children
who turn out great?

5
-

What is the role of parents?