Biological

Biological Approaches in AS Level Psychology

What is the Biological Approach?

The biological approach explains behaviour and mental processes in terms of the structure and function of the brain, the activity of neurotransmitters, genetic inheritance and the influence of hormones. It assumes that mental processes have a physical basis and can be measured objectively.

Key Concepts

• Neuroanatomy – localisation of function in specific brain regions.
• Neurochemistry – role of neurotransmitters such as dopamine, serotonin and acetylcholine.
• Genetics – influence of hereditary factors and gene‑environment interaction.
• Endocrinology – effects of hormones (e.g., cortisol, testosterone) on behaviour.
• Methodology – use of brain imaging, lesion studies, pharmacological manipulation and twin studies.

Major Areas of Study

1. Brain Structure and Function

Research focuses on identifying which parts of the brain are responsible for specific cognitive functions. Key regions include the frontal lobes (executive function), temporal lobes (memory), amygdala (emotion) and hippocampus (long‑term memory consolidation).

2. Neurotransmitters

Neurotransmitters are chemicals that transmit signals across synapses. Imbalances are linked to mental health disorders:

• Serotonin – mood regulation; low levels associated with depression.
• Dopamine – reward and motivation; hyperactivity linked to schizophrenia.
• Acetylcholine – learning and memory; deficits observed in Alzheimer’s disease.

3. Genetics

Behavioural genetics investigates the relative contributions of heredity and environment. Twin, adoption and molecular genetics studies provide evidence for genetic influence on traits such as intelligence, personality and susceptibility to mental illness.

4. Hormones

Hormones act as chemical messengers that affect brain activity. Examples include:

• Cortisol – stress response; chronic elevation can impair memory.
• Testosterone – aggression and risk‑taking behaviour.
• Oxytocin – social bonding and trust.

Key Studies and Findings

Study	Method	Key Findings	Evaluation
Phineas Gage (1848)	Case study – accident causing frontal lobe damage	Personality change demonstrates role of frontal lobes in social behaviour.	Single case; limited generalisability; lack of control.
HM (Scoville & Milner, 1957)	Case study – bilateral hippocampal removal	Severe anterograde amnesia shows hippocampus essential for forming new memories.	Rare surgical case; ethical constraints prevent replication.
Milner et al. (1991) – PET study of language	Positron Emission Tomography (PET)	Increased blood flow in left inferior frontal gyrus during word generation.	Expensive; limited temporal resolution; radiation exposure.
Plomin & DeFries (1990) – Twin studies of IQ	Comparative analysis of monozygotic and dizygotic twins	Heritability estimate for IQ ≈ 0.70, indicating strong genetic influence.	Assumes equal environments; cannot identify specific genes.
McEwen (1998) – Cortisol and memory	Laboratory experiment with cortisol administration	Elevated cortisol impairs retrieval of declarative memory.	Artificial dosing may not reflect natural stress responses.

Research Methods Used in the Biological Approach

Method	Strengths	Limitations	Typical Applications
Lesion studies (e.g., patient HM)	Direct link between brain area and function; natural experiments.	Rare cases; ethical issues; compensatory mechanisms may confound results.	Understanding localisation of function.
Brain imaging (fMRI, PET, EEG)	Non‑invasive; high spatial (fMRI) or temporal (EEG) resolution.	Expensive; indirect measures of neural activity; movement artefacts.	Mapping activity during cognitive tasks.
Pharmacological manipulation	Causal evidence for neurotransmitter involvement.	Side effects; dosage control; ethical constraints.	Studying mood disorders, addiction.
Behavioural genetics (twin, adoption studies)	Quantifies genetic vs environmental contributions.	Assumes equal environments; cannot pinpoint specific genes.	Intelligence, personality, mental illness.

Evaluation of the Biological Approach

• Strengths
  • Provides objective, measurable data using advanced technology.
  • Offers clear causal explanations for many mental disorders.
  • Facilitates development of pharmacological treatments.
• Weaknesses
  • Reductionist – may overlook social, cultural and environmental influences.
  • Ethical limitations restrict experimental manipulation of the brain.
  • Complex behaviours often involve multiple interacting systems, making simple localisation difficult.
• Integration with Other Approaches
  • Biopsychosocial model combines biological, psychological and social factors.
  • Behavioural genetics bridges biological and environmental perspectives.
  • Neuropsychology links brain data with cognitive theories.