Research, biological explanations and evidence
What you must know
This domain links nervous system structure to behavior. Be able to describe neurons (dendrites receive, axons transmit, myelin speeds conduction, terminal buttons release neurotransmitters across the synapse). Know excitatory vs. inhibitory signals and that a neuron fires when threshold is reached (all-or-none). Distinguish agonists (mimic or enhance a neurotransmitter) from antagonists (block it). Map the nervous system: central (brain, spinal cord) vs. peripheral, with the peripheral split into somatic (voluntary skeletal muscle) and autonomic (involuntary), and autonomic split into sympathetic (arousal, fight-or-flight) and parasympathetic (calming, restoration).
Brain regions: medulla (breathing, heart rate), pons (bridge, sleep), cerebellum (balance, motor coordination), reticular formation (arousal), thalamus (sensory relay), hypothalamus (temperature, hunger, endocrine control), amygdala (fear, emotional salience), hippocampus (memory consolidation), and the cerebral cortex with its four lobes (frontal: planning, motor, Broca's area; parietal: somatosensory; temporal: hearing, Wernicke's area; occipital: vision). Know hemispheric specialization and split-brain findings.
Traps
Questions swap Broca's (production, frontal) and Wernicke's (comprehension, temporal). They confuse the thalamus (relay) with the hypothalamus (regulation). They call the sympathetic system "calming." They treat a neurotransmitter as good or bad rather than context-dependent. They assume brain regions work alone, when questions test localization vs. distributed processing.
Worked example
In a simplified classic localization exercise, language comprehension is associated with Wernicke-related networks and speech production with Broca-related networks. Real language function is distributed, and one observation is not sufficient for a clinical diagnosis.
Rule of thumb
When a question names a structure, ask what function it serves, then match the behavior in the stem to that function.
Research evidence andlimits
A psychological explanation needs a testable question, clear operational definitions and an appropriate method. Distinguish correlation from a causal conclusion. Random assignment concerns allocation to conditions; random sampling concerns how participants are selected. A confound changes with the proposed explanatory variable and can provide an alternative explanation. Reliability concerns consistency, while validity asks whether the measure or inference supports its intended interpretation. Biological explanations do not make social or cognitive evidence irrelevant. Interpret classic localization examples as simplified models of function, not permission to diagnose a realperson from one observation. Brain functions involve interacting networks and individual differences. Evaluate consent, privacy, proportionate risk and the limits of generalizing from a particular sample. A result is not made causal merely because it contains a brain measurement or a numerical correlation.