Genetic and Environmental influences

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  • Created by: gracepxx
  • Created on: 18-05-16 17:32

P1 - Intro

Long standing debate whether you are the product of your genes or of your environment

Nature refers to your abilities present at birth and any ability determined by genes, including those that appear through maturation

Nurture - learning behaviours through interactions with the environment, including physical and social world

Genetic influence = nature, envinronmental = nurture, interactionalists = combination

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P2 - Intelligence

Genetic influences have strong influence on intelligence - twin and adaoption studies suggest large component of IQ is genes

Chorney et al (1998) - used gene mapping studies to identify individual genes that are associated with having high IQ 

However, equally strong evidence has been found for effects of nurture on intelligence 

The flynn effect shows how all IQs have increased by up to 20 points in 30 years due to environmental enrichment

Studies also show varience could be due to socioeconomic status of the children - for children from impoverished families, genes accounted for hardly any of the variance

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P3 - Mental illness

Also looked at in terms of twin and adoption studies - show closer individuals are genetially, the higher chance of them developing same mental disorder

Concordance rate for schizophrenia is 40% in MZ and just 7% in DZ according to Joseph (2004)

Despite this, research shows there is clear environmental effect on development of mental disorder

The diathesis-stress model shows this by representing both nature and nurture - individual may have genes to illness (diathesis) but only develop it under certain conditions (stress)

Adopted children who had schizophrenic biological parents were more likely to become ill themselves only if the adaptive family were also disturbed - illness only manifested itself in the appropriate environmental conditions despite being genetic, showing support for nurture side of debate

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P4 - Evolutionary explanations

Leads to argument genetics have stronger influence on behaviour

Any explanation of this follows trhat behaviour which promotes survival and reproduction will be naturally selected because it is adaptive and so genes will be passed on to future generations

Buss (1989) demonstrated evolutionary process, showing that certain elements of mate choice are universal and sought after by all, such as the tendency for women to value ambition and industriousness more than males

However, such genetic behaviours modified by culture or environment

There were exceptions to general tendencies which is described by cultural relativism

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P5 - Epigenetics

Another argument that takes on the interactionalist appraoch is that environmental effects are, infact, inherited

Research has uncovered a new understanding of genes called epigenetics

This refers to material in each cell of the body that turn genes on or off 

Life experiences, nutrition and stress control how these genes are turned on/off

The epigenetic material they inherited is derived from environmental effects controlling their behaviour 

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P6 - Aggression

Bandura's idea that agessive behaviour is learned through obervatiob abd vicarious reinforcement are views upheld by those who maintain the environment influences our behaviour 

Bandura et al (1961) study using Bobo illustrated important aspect of theory using SLT - however, doesn't mean biological factors are ignored but that a person's biological makeup creates a potential for aggression and it is the expression of the agression that is learned

Coccaro et al (1997) supports importance of biological factors - found 50% of varience in aggressive behaviour in twin pairs could be attributed to genetic factors 

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P7 - Neural plasticity

Research into neural plasticity and impacts on behaviour

Blakemore and Cooper's research with kittens shows how experience of environment impacts innate systems

This is an example of neural plasticity and how the brain may be changed by the environment and experience

A study on London taxi drivers shows that the region of their brain associated with spatial memory was bigger than those in non-taxi drivers

This was because their hippocampi had responsed to increased use, not because they were born that way - Magurie et al 2000

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P8 - Influence of genes on environment

Interactionalists such as Plomin et al (1977) suggests there are indirect effects of genes 

Reactive influences are where genetic factors create an infant's microenvironment - a child who is genetically more agressive provokes agression in others and their response becomes part of their environment and so their genes have impacted their environment

Passive influences describe how parent's genes determine aspects of behaviour indirectly - a parent with a genetically determined mental illness creates an unsettled environment,developing a mental disorder in the child due to indirect, passive effects of genetics on environment

Active influence, or niche picking (1983) believes that as children grow older they seek out experiences and environments that suit their genes, explaining why the influence of genes increases and the influence of shared environment gradually decreases with age 

It is your genes that influence kind of things you prefer and your environmental selections

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