The biological approach: the genetic basis of behaviour: genotype,…

The idea

The biological approach roots behaviour in physical processes. It distinguishes between the genotype (actual genetic makeup) and the phenotype (observable characteristics from the interaction of genes and environment). For example, a genetic vulnerability to depression (genotype) may only manifest as the disorder (phenotype) if triggered by stress. Evolution explains behaviour through natural selection, where adaptive traits enhance survival. Biological structures, such as the amygdala, influence behaviours like aggression. Neurochemistry involves neurotransmitters, like serotonin, regulating mood. Cognitive neuroscience bridges biology and cognitive psychology, using brain scans like fMRI to map mental processes to specific neural structures.

What earns the marks

• Define genotype as the genetic constitution of an individual and phenotype as the observable characteristics resulting from the interaction of the genotype with the environment.
• Explain evolution in terms of natural selection, where genetically determined behaviours that enhance survival and reproduction are passed to future generations.
• Identify specific biological structures, such as regions of the brain or the nervous system, and explain their direct influence on behaviour.
• Describe the role of neurochemistry, specifically how neurotransmitters transmit messages across synapses to affect behaviour and mood.
• Outline cognitive neuroscience as the scientific study of the biological structures that underpin cognitive processes, often using neuroimaging techniques.

Common mistakes and how to put them right

• Confusing genotype and phenotype.

  Put it right: Clearly state that genotype is an individual's genetic constitution or makeup, whereas phenotype is the observable physical or behavioural expression that can change due to environmental factors.

• Stating that evolution causes individuals to adapt during their lifetime.

  Put it right: Explain that evolution operates across generations through natural selection of advantageous genetic mutations.

• Treating cognitive neuroscience as identical to the biological approach.

  Put it right: Specify that cognitive neuroscience is a distinct, interdisciplinary field combining cognitive psychology and biological neuroscience.

Exam tips

• Use twin studies as evidence when evaluating the genetic basis of behaviour, noting that monozygotic twins rarely show 100% concordance, which highlights the role of the environment in shaping the phenotype.
• When discussing neurochemistry, always link a specific neurotransmitter to a specific behaviour or disorder, such as low serotonin levels in depression.
• Prepare to evaluate the biological approach by discussing its scientific methods, such as fMRI scanning, as a strength, and its biological determinism as a limitation.