The Biological Approach

What is the biological approach?

To fully understand human behaviour, we must study biological structures, functions and processes. Assumes a biological basis for behaviour

Examples of biological structures, functions and processes

Genetics, neurotransmitters, hormones, brain structures

Genetic basis of behaviour

Extent to which behaviours are inherited. Inheriting psychological traits is questioned. A genetic explanation of behaviour is that genes influence traits, characteristics, behaviours

How is genetic bias for specific traits studied?

Use twin studies to investigate if psychological characteristics have genetic bias. Achieved by analysing concordance rates, extent to which twins share the same characteristic

Monozygotic and dizygotic twins

Monozygotic are identical, dizygotic is fraternal

How do twin studies work?

MZ and DZ twins are compared to each other. Begin by looking at one twin proband. If this twin has a specific trait, the researchers see if their twin sibling has the same trait

How are the rates of agreement measured in a twin study?

Use concordance rates. A high concordance rate shows evidence of a casual connection between the twin type and the trait/behaviour

What results would be seen for a MZ twin and a DZ twin?

MZ twins to be the same, they share 100% of the same genes. DZ twins share about 50% of the same genes, share the same environment

Genotype

A person’s particular set of genes that make up their DNA. Made up of a combo of alleles (different versions of the same gene). MZ twins have the same genotype

Phenotype

Observable characteristics of an individual from the expression of its genotype with the environment. Ex height, eye colour, hair texture, blood type

Evolution

Darwin proposed a theory of natural selection. Any genetically determined behaviour that enhances the chance of survival will continue in the future. The individual is more likely to survive, reproduce and pass on the traits

Natural selection

Environmental factors

Can influence a person’s phenotype. A person’s genotype could predispose them to specific behaviours but if the specific environmental factors isn’t in place then the genotype may never express in the phenotype

Biological structure

Any physical part or system in the body

Neurochemistry

Action of chemicals in the nervous system, our behaviour relies on chemical transmission. Uses neurotransmitters, an imbalance of neurochemicals in the brain could be a possible cause of mental health conditions