Transcript Chapter 3 Heredity and Environment

Life Span Development
Theories of Development – Ch. 2
Heredity and Environment – Ch. 3
June 10, 2004
Class #2
Chapter 2: Theories of Development
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Questions Central to Theories
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Do early experiences of breast-feeding or bonding or abuse
linger into adulthood, even if they seem to be forgotten?
How important are specific school experiences in human
intelligence?
Can a person develop moral values without being taught them?
Does culture elicit behavior, e.g., is violent crime more common
in one place than another; for example, in China or Canada?
If your parents or grandparents schizophrenia, or alcoholism, will you
develop them suffer from depression,?
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Of all questions—Why or Why not? When and
How?, So What?
What Theories Do
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Developmental theory—
systematic statement of
principles and generalizations
that provides a coherent
framework for studying
development
What Theories Do…
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Theories
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form basis for hypotheses that can be
tested by research studies
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formulating right question is more difficult
that finding right answers
generate discoveries
offer insight and guidance by providing
coherent view
Types of Theories
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Different Types
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grand theories—comprehensive, traditional theories
originated in psychology
minitheories—theories that focus on specific area of
development
 originated more in sociology through study of social
groups and family structures
emergent theories—new, comprehensive groupings of
minitheories
 multidisciplinary approach includes historic events
and genetic discoveries
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Grand Theories
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Grand Theories—powerful
framework for interpreting and
understanding change and
development that applies to all
individuals in all contexts, across all
contents
Psychoanalytic Theory
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Psychoanalytic theory interprets
human development in terms of
motives and drives
Behaviorism
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Behaviorism is built on laws of
behavior and processes by which
behavior is learned
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focus: ways we learn specific
behaviors that can be described,
analyzed, and predicted with
scientific accuracy
Laws of Behavior
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Conditioning—any process in which behavior is learned
Classical conditioning —Ivan Pavlov
process by which a neutral stimulus become
associated with a meaningful stimulus
 stimulus and response (respondent conditioning)
Operant conditioning—B. F. Skinner
 process by which a response is gradually learned via
reinforcement or punishment
 also called instrumental conditioning
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Social Learning
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Extension of learning theory that includes
modeling which involves people observing
behavior and patterning their own after it
Modeling
 process in which people observe, then copy
behavior
 Alfred Bandura—most likely to occur if
model is admired or observer is
inexperienced
 self-efficacy motivates people to change
themselves and their contexts
Cognitive Theory
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Focuses on the structure and
development of thought processes,
which shape perceptions, attitudes,
and actions.
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Example: Jean Piaget’s 4 Stages
Emergent Theories
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Emergent theories arise from several
accumulated minitheories and may be
the new systematic and
comprehensive theories of the future
Sociocultural Theory
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Seeks to explain growth of individual
knowledge, development, and
competencies in terms of guidance,
support, and structure supplied by
the society
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human development is the result of
dynamic interaction of the developing
persons and their surrounding culture
Sociocultural Theory
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Guided participation—tutor engages
learner in joint activities, providing
instruction and direct involvement in
learning
Apprenticeship in thinking—mentor
provides instruction and support
needed by novice
Sociocultural Theory
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Zone of proximal development—range of
skills learner can perform with assistance
but not independently
 learner is drawn into learning by teacher
Cultural variations: Basic principles are
universal, but skills, challenges, and
opportunities vary from culture to culture,
depending on the values and structures of
the culture’s society
Epigenetic Theory
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Emphasizes the interaction between genes and
the environment—the newest developmental
theory
 stresses that we have powerful instincts and
abilities that arise from our biological
heritage. Timing and pace of certain
developmental changes are genetically guided
 performism—everything is set in advance by
genes and then is gradually manifested in the
course of maturation
What Theories Can
Contribute
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Psychoanalytic theory has made us aware of importance
of early childhood experiences
Behaviorism has shown effect of immediate
environment on learning
Cognitive theory helps us understand how intellectual
process and thinking affect actions
Sociocultural theory has reminded us that development
is embedded in a rich and multifaceted context
Epigenetic theory emphasizes interactions between
inherited forces and immediate contexts
Eclectic Perspective
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This is the approach taken by most
developmentalists in which they apply
aspects of each of the various theories
rather than staying with just one
The Nature-Nurture
Controversy
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Is it heredity or environment that shapes
us?
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How much is a result of any given
characteristics, behavior or pattern
of development is a result of genes
and how much is a result of experiences
Policy and practice: nature/nurture theories are
implicit in many public policies
Theoretical Perspectives on
Hyperactivity and Homosexuality
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AD/HD and homosexuality—How and
to what extent are nature and
nurture involved in each case?
Evidence from AD/HD research that
it can come from either
Theoretical Perspectives on
Hyperactivity and Homosexuality
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Earlier assumptions about homosexuality: more
nurture than nature. As hypotheses tested,
nurture was revealed as less crucial
 sexual orientation may be a matter of nature
 sexual expression may be a matter of
cultural attitude (nurture) but not sexual
orientation
 evidence supporting nature as main factor
(e.g., affect of genetic linkage, prenatal
hormones)
Theoretical Perspectives on
Hyperactivity and Homosexuality
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Ideology often adds to complexity
and polarization of opinions on many
subjects when nature and nurture are
considered
Important to separate assumptions
from facts
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done via research and testing of
hypotheses
Why is someone gay or straight?
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Psychologists really don’t fully understand
the causes of sexual orientation
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Lets look at some biological explanations…
 Concordance rates: MZ > DZ
 A homosexual gene?
 LeVay (1991): INAH3
Concordance rates
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Eysenck (1964)
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Bailey and Pallard (1991)
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Reported a higher incidence of homosexuality among men
whose MZ twin was gay than among men whose DZ twin was
gay
Twin study
Homosexual men
Co-twin was more than twice as likely to be homosexual if the
twins were MZ
Bailey, Pallard, Neale, & Agyei (1993)
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Replicated earlier study using homosexual women
Same results
A homosexual gene?
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Hamer et al. (1993)
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Examined families of homosexual men
Found significantly more gay relatives on
mother’s side of family
Maternal uncles and sons of maternal aunts
(male cousins)
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Might their be a homosexual gene on the X
chromosome?
Hamer et al. (1993)
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They continued the investigation and
found that most of the homosexual men
had a region in the X chromosome that
was similar suggesting a genetic basis…
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But not for all suggesting another reason
Important implication to all this:
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It may be possible for non-homosexual
women to pass on this gene
LeVay (1991)
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Examined hypothalamic tissue from:
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19 gay men, all of whom died of AIDS
16 heterosexual men, six of whom had died of
AIDS
6 women of unknown sexual orientation
LeVay (1991)
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Found neuroanatomic differences between
homosexual and heterosexual men…
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INAH3 was two to three times larger in
heterosexual men than in gay men
LeVay (1991)
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As the first suggestion that there was a
neuroanatomic difference between gay
and heterosexual men, LeVay's finding
garnered a great deal of public attention,
and a great deal of controversy about
both its scientific and its social implications
Other reasons???
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Investigators have assessed every possible
psychological cause of sexual orientation
that you could think of…
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The findings when looking at the backgrounds
of those that are heterosexual, homosexual,
or bisexual are?
Chapter 3:
Heredity and Environment
What is a gene made out of?
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Genes are made from
chromosomes. People have 23
pairs of chromosomes.
DNA consists of a double helix,
whose parallel strands consist of
both pairs held together by
hydrogen bonds.
Each chromosome in the DNA
contains instructions for
stringing together amino acids.
These instructions are used in
different combinations with the
chemicals adenine (A), thiamine
(T), guanine (G) and cytosine
(C).
Conception
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Fertilized egg with two pronuclei
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Within 72 hours it’s divided into 8 cells
Once the sperm penetrates the
egg, the two nuclei fuse to
become one, with 23
chromosomes from the father
and 23 chromosome from the
mother.
A zygote is the single cell
formed from the fusing of the
sperm and ovum.
After four days there are about
100 cells and it is now called a
blastocyst.
The organism’s genetic
inheritance is set for life once
the chromosomes pair up.
Is it a boy or a girl?
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In the 23rd pair of
chromosomes women
are XX and men are
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XY
Every ovum that the
woman produces is XX
Men will produce half 2.
Y sperm and half X
sperm because his
23rd pair contain both
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Different factors can
determine the sex of the
embryo such as when:
A man carries a gene
that causes his X or Y
gene to be immobile.
The alkaline or acidity
levels of a woman’s
uterus can help either
the X or Y gene.
Stress can cause an XY
embryo to be expelled.
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A zygote may split in the early
stages of development, which
creates separate identical
zygotes
Monozygotic twins are
identical because they originate
from the same zygote
Dizygotic twins are formed
when two separate ova are
fertilized by two separate sperm.
They share half their genes,
similar to siblings.
Factors that can increase the
chances of twins are:
A woman’s age
A woman’s ethnic group
Medical intervention
A family history of having
twins
Let’s split!
Mary-Kate and Ashley Olsen
What else do genes do?
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Once the zygote reaches it’s
eight-cell stage, cells begin to
specialize to become different
parts of the body.
Genes code protein so that
they can give instructions to
other genes to shut on and off
at different stages of life. For
instance, to absorb
nourishment, to multiply and
to die.
Phenotype is a person’s
actual appearance and
behavior, which are the results
of both genetic and
environmental influences
How do gene’s interact?
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Additive genes interact
additively so that there are
fairly equal contributions from
all the genes involved. They
affect traits such as skin color
and height.
A dominant gene is the
member of an interacting pair
of alleles whose influence is
more evident in the
phenotype.
A recessive gene is the
member of an interacting pair
of alleles whose influence is
less evident in the phenotype
X-linked genes are genes
located on the X chromosome.
Genotype vs. Phenotype
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Genotype is an
organism’s entire genetic
inheritance, or genetic
potential. For instance,
you might have inherited
the genes that could lead
you to become a great
mathematician. Another
example is that you may
have inherited blue eyes.
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Phenotype is a person’s
actual appearance and
behavior, which are the
result of both genetic and
environmental influences.
For instance, you might
have the genes to
become a great
mathematician, but
without the right
environment, your talent
may never be recognized.
What is behavior genetics?
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Behavior genetics is
the study of the genetic
origins of psychological
characteristics, such as
personality patterns,
psychological disorders
and intellectual abilities.
Sadness is one personality trait that is
studied in behavior genetics.
Alzheimer’s Disease
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Alzheimer’s is only purely
genetic when it occurs
before the age of 50
European Americans are
at the highest risk of
Alzheimer’s as they’re
more likely to carry the
gene
The ApoE4 gene carry’s
Alzheimer’s
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At age 85 the risk of
senility levels off
Non-genetic influences,
such as lifestyle, play a
big role in Alzheimer’s
By being physically active
and mentally alert, you
reduce the risk of
developing Alzheimer’s
disease
Schizophrenia
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“Roses are red, violets are blue, I’m a
schizophrenic and so am I.”
Bill Murray, What About Bob?
Approximately 1 percent of
the population is diagnosed
with schizophrenia.
Schizophrenia is a genetic
trait that is that also
appears to be strongly
influenced by the
environment.
Physical elements, such as
injury to the head, can also
bring on schizophrenia.
Alcoholism
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Inherited biochemistry makes some
people highly susceptible to alcohol
addiction
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addictive pull can be overpowering, or weak,
or something in the middle
may explain ethnic variations
Alcoholism
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Not simply a biochemical reaction—it is
psychological and physical, and biological;
thus alcoholism is polygenetic, with
alcoholics inheriting a combination of
biochemistry-affecting and temperamentaffecting genes
Culture counts too (whether alcohol is
present in environment)
Chromosomal and Genetic
Abnormalities
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Here we notice disruptions of normal
development
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origins of genetic and chromosomal
abnormalities
misinformation and prejudice add to
problems of people with these abnormalities
Genetic and Chromosomal Abnormalities
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A chromosomal abnormality
occurs when there or more or
less than 23 chromosomes in a
gamete
Genetic abnormalities arise
when proteins do not code
properly
Most abnormal zygotes simply
never begin to develop. The
majority of the rest are not
carried to term as they are
spontaneously aborted
(miscarried).
Muscular Dystrophy Association Summer
Camp
Brandon, Florida
Down Syndrome
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Some people with down syndrome are quite
capable of doing things themselves, like this
woman who does her own grocery shopping.
The most common extra
chromosome condition is Down
syndrome.
It affects people in varying
degrees
Young children with Down
syndrome are likely to have a
nice disposition
At age 30, people with Down
syndrome begin to age rapidly
Life expectancy rate is low
Genetic Abnormalities:
Huntington’s Disease
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Most dominant disorders are
not disabling, however
Huntington’s disease is one of
the few that is.
It doesn’t appear until a
person is between 35 and 45.
By that time the person may
have children, who have a
50/50 chance of inheriting it
Testing can be done to see if a
person carries the gene
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There is no cure for
Huntington’s disease
The first signs of Huntington’s
disease are clumsiness,
forgetfulness and involuntary
movements
As the disease progresses, the
ability to think and control
movements becomes harder
and harder
Eventually, the individual is
unable to do anything
Genetic Abnormalities:
Tourette Syndrome
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Wolfgang Amadeus Mozart was thought to
have had Tourette Syndrome.
Tourette syndrome is a
dominant disorder that
can cause uncontrollable
tics and outburst.
It is 3 to 4 times more
likely to occur in boys
30% of people with
Tourette syndrome have
uncontrollable tics and
outbursts
The other 70% have just
an occasional twitch and
other slight problems
Genetic Counseling and Testing
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Genetic counseling is a
process of consultation and
testing that enables
individuals to learn about
their genetic heritage,
including conditions that
might harm any children they
may have.
People who should have
genetic counseling are those
with:
Close relatives with a severe
genetic condition
Histories of miscarriages
Women over age 35 and men
over age 40
Couples from the same
ethnic group or close relative
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Some people prefer not to be
genetically tested if it might
reveal an incurable genetic
disorder, but they are more
likely to consider it when they
are deciding whether or not to
have children.
Genetic counselors are often
able to give couples odds on
whether or not their children
could inherit their genetic
disorders
Scientists and genetic
counselors advice high risk
couples to use prenatal testing
to determine any health
problems the baby may have
Conclusion
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Which plays a bigger
role in human
development,
heredity or
environment?
Is Kate Hudson’s ability as an actor influenced
by her environment or genes? Do you think
her environment or her genes influenced her
career choice?