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THE BIOLOGICAL APPROACH
~BASIC ASSUMPTIONS~
All thoughts, feelings and behaviours have a biological basis
Our behaviour is adaptive and has an evolutionary purpose
~GENETIC BASIS OF BEHAVIOUR~
Twin Studies
Adoption Studies
Family Studies
Concordance Rate: Concordance is the extent in which a trait matches or is shared with another person. The higher the concordance rate %, the higher the chance that the trait is genetic. The lower the concordance rate %, the higher the chance that the trait is environmental.
~TWIN STUDIES~
MONOZYGOTIC twins share 100% of their DNA
DIZYGOTIC twins share 50% of their DNA
→ Twin studies receive criticism as they share the same environment and are treated the same
GOTTESMAN & SHIELD’S (1966)
Uses twin studies to compare monozygotic and dizygotic twins.
Tested schizophrenia in 24 monozygotic twins, and 33 dizygotic twins.
The concordance rate for severe schizophrenia was 75% for monozygotic twins, and 24% for dizygotic twins.
~ADOPTION STUDIES~
CROWE’S STUDY (1972)
Compared adopted children whose mother had a criminal record
50% of those adopted children also developed a criminal record by 18, compared to 5% of adopted children in the control group
~FAMILY STUDIES~
Family studies use concordance rates to measure inheritance
WEISSMAN (2005)
Longitudinal research into 3 generations.
He found that grandchildren were 60% more likely to develop depression if their grandparents had the disorder.
~EVOLUTION~
→ Darwin stated that individuals with genes best suited to their environment are more likely to survive and reproduce, thus passing on these characteristics. He suggested that this happens naturally over generations, but can be replicated artificially.
GENOTYPE → genetic code in DNA that is inherited
PHENOTYPE→ how genes are expressed physically
Genotypes have a genetic influence, whereas phenotypes have an environmental influence.
Genotype + Environment = Phenotype
This is supporting evidence that our biology and the environment interact.
EVALUATION
→ IGNORES THE INFLUENCE OF NURTURE ON BEHAVIOUR
One limitation of the cognitive approach is that it places too much emphasis on nature, and ignores the influence of nurture on behaviour.
Psychologists who support the biological approach believe that behaviour is inborn and innate, due to our genetics and brain structure.
Research today suggests that behaviour can best be explained using both nature and nurture together.
Therefore, as this approach only focuses on one, it lacks ecological validity.
→ IT IS BIOLOGICALLY REDUCTIONIST
One strength of the biological approach, is that it is reductionist, which is praised for forming the basis of scientific research.
This is due to the fact that often the investigations use scientific testing.
For example, in the biological approach, it breaks down human behaviour into specific biological processes.
These findings increase the scientific credibility of the approach, as results supporting these conclusions were produced as a result of a scientific investigation.
→ IT IS BIOLOGICALLY DETERMINISTIC
Another limitation of the biological approach, is that it is deterministic.
For example, psychologists who support this approach believe that behaviour is caused by internal, biological forces that are outside of our control.
This approach can be criticised as it ignores the influence of conscious decision-making processes on behaviour.
This leads to a lack in ecological validity.
→ IT IS NOMOTHETIC
Another limitation of the biological approach, is that it overlooks the richness of human experience.
In this approach, they use brain scans to produce quantitative data about the activity of the brain.
The lab studies used to conduct this research lack external validity, and make it difficult to generalise the findings outside of the research environment.
