Biological Psychology: Nervous System, Brain and Behaviour
Core concepts
Biological psychology explains behaviour through physiology. You must know the neuron (dendrites receive, axon transmits, myelin speeds conduction, terminal buttons release neurotransmitters across the synapse) and the distinction between excitatory and inhibitory neurotransmitters. Understand the divisions of the nervous system: central (brain, spinal cord) versus peripheral, with the peripheral split into somatic and autonomic, and the autonomic split into sympathetic (arousal, fight-or-flight) and parasympathetic (rest, restoration). Know the endocrine system and hormones such as adrenaline and cortisol.
Localisation of function is examinable: frontal lobe (planning, motor control, Broca's area), parietal (somatosensory), temporal (auditory, Wernicke's area), occipital (vision). Know the corpus callosum and split-brain findings, plus hemispheric specialisation.
Common traps
- Confusing the sympathetic nervous system with the somatic nervous system; the somatic system controls voluntary skeletal muscle, the autonomic controls involuntary organs.
- Claiming a function is entirely localised; modern answers should acknowledge distributed processing and plasticity.
- Confusing neurotransmitters (fast, synaptic) with hormones (slower, bloodstream).
- Describing split-brain research without noting it involved small samples of epilepsy patients, limiting generalisation.
Rule of thumb
When asked to link biology to behaviour, always name the structure, state its normal function, then explain the behavioural consequence of its activity, damage or manipulation. For example, hippocampal damage impairs consolidation of new declarative memories while leaving older memories relatively intact.
Worked example
Question: Why does adrenaline increase heart rate during stress? Answer: the sympathetic nervous system stimulates the adrenal medulla to release adrenaline into the bloodstream, which acts on receptors in the heart to increase rate and force of contraction, preparing the body for action.