Overview
This lecture introduces the biological approach in psychology, focusing on how brain structures, neurochemistry, genetics, and evolution influence human behavior.
The Biological Approach: Foundations
- The biological approach explains behavior through biological processes in the brain, body, and genes.
- Psychologists divide the brain into areas with different roles that communicate with each other and the body.
- Hormones (chemical messengers) and neurotransmitters (brain chemicals) influence behavior.
- Genes determine brain structure, which is further shaped by evolution for survival advantages.
Biological Structures and Behavior
- The endocrine system of glands releases hormones that impact behavior (e.g., adrenaline triggers fight-or-flight).
- The brain’s main areas: brain stem (core functions), cerebellum (movement/balance), cerebrum (thinking, perception), and limbic system (emotions).
- Localization of function means specific brain areas control specific behaviors.
- Case studies (e.g., Broca's area and speech) show brain regions’ roles in behavior.
Neurochemistry and Behavior
- Neurons communicate via synapses, where neurotransmitters carry signals between cells.
- Neurotransmitters can be excitatory (increase activity) or inhibitory (decrease activity).
- Common neurotransmitters: serotonin (well-being), dopamine (reward/pleasure), noradrenaline (attention), glutamate (learning/memory).
- Drug therapies like SSRIs increase serotonin to treat depression and OCD, showing neurochemistry influences behavior.
Genetics and Behavior
- Genes (sections of DNA) code for traits and influence behavior (e.g., candidate genes for OCD).
- Genotype is a genetic code; phenotype is the observable trait or behavior.
- Family and twin studies show higher concordance rates for OCD among close relatives, supporting genetic influence.
- Genotype expression can depend on environmental factors (stress-diathesis model).
Evolution and Behavior
- Evolutionary psychology argues behaviors that help survival (e.g., aggression) are inherited.
- Natural selection favors traits and behaviors that increase reproductive success.
- Modern human traits may reflect ancestral adaptations.
Evaluation of the Biological Approach
- Supported by scientific research: brain imaging, genetic analysis, and drug trials.
- Led to effective treatments for mental health conditions.
- Criticized for biological determinism, possibly undermining personal responsibility and overemphasizing biology over environment.
Key Terms & Definitions
- Endocrine system — network of glands that release hormones.
- Hormone — chemical messenger traveling in the bloodstream.
- Neurotransmitter — brain chemical enabling communication between neurons.
- Genotype — genetic code of an individual.
- Phenotype — observable traits or behaviors.
- Concordance rate — likelihood of shared trait/disorder among relatives.
- Localization of function — specific brain areas control specific behaviors.
- Diathesis-stress model — disorders result from genetic vulnerability plus environmental stress.
- SSRIs — drugs (Selective Serotonin Reuptake Inhibitors) increasing serotonin availability.
Action Items / Next Steps
- Download and complete the matching worksheet for this lecture.
- Review the biological approach in relation to OCD, especially for exam paper one.
- Study key research studies: Broca’s case, SSRIs’ effects, and twin/family genetics research.