5 nature and nurture

8/14/2019 5 Nature and Nurture

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Nature vs. Nurture

One of the most important

questions in psychology is:

How much of human

behavior is caused by our

physical make up, our

genes (nature) vs. how

much is what we learn byexperience in our

environment (nurture). How much of your personalityis from your parents genetics

And how much did you just learn

From living your life?


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The Human Genome

The human genome is a complete set of

instructions for making a human. The human genome has 3 billion bonded

pairs of nucleotides organized as DNA

sequences. They are being mapped out so

that doctors will know what each one does.


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The Human Genome Project

This Human Genome Project hasthe potential to save more lives than

any other technology, it also raisesserious ethical questions regardingcloning and human engineering.

Human traits are influenced by genecomplexes many genes workingtogether. There is no angry gene,but a number of genes workingtogether could make someonespersonality more aggressive. This

type of study is called moleculargenetics.


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Evolutionary Psychology

Natural Selection - The theory that organisms with

the genetic trait variations are more likely to

reproduce and survive.

For example people are predisposed to enjoy sweets

and fats because our ancestors knew that food

would help them survive famines however, now

this trait can be a cause of obesity in a world wherefood is plentiful, perhaps in a million years there will

be people who are mostly predisposed to eat less?


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Gender

In general men are more likely to initiate sexual

activity regardless of culture or where you live.Men are more attracted to youthful, healthy

looking, females who waists are a third narrower

than the hips (a sign of many child bearing years

to come).Woman are attracted to healthy looking, mature,

dominant, bold and affluent men traits that

denote the ability to support and protect.


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The most important human trait

The most important human trait however, is

our amazing ability to use our mind andreason to adapt to any situation and

condition. This perhaps more than anything

else has made humans a successful species

as well as one that is very hard to predict anddefine.


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Twin Studies

Behavior genetics - The study of the

relative power of genes or environment toinfluence behavior.

Environment every non genetic influence.

Includes prenatal nutrition, post natal care,

etc. Psychologists have extensively used Twin

Studies to study nature vs. nurture.


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Twin Studies

Identical Twins Twins whodevelop from a single

fertilized egg that splits intwo, creating two geneticallyidentical people.

Fraternal Twins Twinswho develop from twoseparate eggs and sperm.Genetically they are nocloser than normal sistersor brothers but they doshare a fetal environment.


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Identical Twins developed from

the same egg and sperm

Fraternal twins from a racially mixed

marriage. They come from two separate

eggs and sperm coming together.

Identical vs. Fraternal


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Separated Twins/Adoptive Studies

By studying separated twins and adoptive

children who dont grow up with their parentswe can learn even more about how heredity

and environment affect behavior.

For example will adoptive children have

temperaments (how a person emotionallyreacts to things) closer to their birth parents

or to their adoptive parents?


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Development video

http://www.learner.org/resources/series138.ht

Heritability the proportion of variationamong individuals that we can attribute to

genes. This does NOT apply to individual

circumstance but only measurements among

people as a whole.
http://www.learner.org/resources/series138.html?pop=yes&pid=1502http://www.learner.org/resources/series138.html?pop=yes&pid=1502


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Gene-Environment Interaction

Genes and the environment both influenceus but its more complicated than thatbecause they also continuously influenceeach other.

For example, a baby with a predisposition tosmile a lot not only inherited that trait, butbecause people will want to play with thatbaby more they will also be influenced bytheir environment!


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Infant Development

Prenatal environment is very important for infant

development, even placenta placement canaffect twins and cause one to thrive more than

the other.

Experience causes brain development. Up to

20% more neural synapses have been recordedin rats that have enriched environments to

develop in. Attention is needed for the brain to

develop. Some animals who receive no attention

after birth even if they are fed regularly will die.


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Other Environment Influences

Peers Children often listen to their peers more

than their parents. Teens almost always doCulture People self enforce culture norms such

as personal space. Memes are used to describe

the creation of cultural ideas that are passed on.

Culture also affects child rearing promotingindependent ideals or teaching loyalty to the

group


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Gender Nature or Nurture?

The physical characteristics of male and

female are obviously affected by nature.However, research shows that mental

dispositions can be affected as well by

genetic control of hormones.

Nurture controls gender roles or what societyexpects a certain gender to do.


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Social Learning Theory

Theory that we learn social behavior by

observing and imitating what we see beingrewarded and punished.

5 nature and nurture

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