Biological Approach in Psychology

Methods Used in Biological Psychology

1. Genetic Studies and Twin Studies

• Twin Studies: Compare behavioral likeness of identical twins (genetic relatedness 1.0) with fraternal twins (genetic relatedness 0.5).
  • Types of Twins:
    • Monozygotic = identical twins (share 100% genetic information).
    • Dizygotic = fraternal twins (share 50% genetic information).
  • Concordance Rates: Higher rates in identical twins suggest genetic influence on traits.
  • Traits Influenced by Genetics:
    • Height: High genetic influence (~90%).
    • IQ: 50-70% genetic influence; mean correlation for identical twins ~0.73.
    • Personality Traits: 50% genetic influence.
    • Other Traits: Include sexual orientation, job satisfaction, diet preferences.
  • Research Example: Bouchard and McGue (1981) on IQ correlations between family members.
  • Criticisms: Methodological flaws, shared environments in twins raised apart.

2. Electroencephalograms (EEGs)

• EEGs: Record electrical activity of the brain. Used to study sleep stages, including REM sleep which is associated with dreaming.

3. Brain Imaging (MRI, PET, EEG)

• Brain Imaging Techniques:
  • fMRI and PET scans map brain areas to cognitive functions.
  • CAT scans provide 3D images of brain areas.
  • PET scans use radioactive markers to study brain activity and energy use.

4. Neuro Surgery

• Case Study of H.M.: Surgery to cure epilepsy removed hippocampus, leading to severe anterograde amnesia. Demonstrates hippocampus's role in memory.

Critical Evaluation

Limitations

• Reductionism: Focuses only on biological factors, ignoring psychological/social influences.
• Determinism: Suggests behavior is biologically determined, affecting personal agency.
• Causality Issues: Research often correlational, not causal.
• Ecological Validity: Controlled lab settings may not reflect real brain activity.
• Side Effects of Treatments: Biological treatments can have significant side effects.

Strengths

• Scientific Methods: Use of objective research methods like brain imaging.
• Real-world Applications: Development of pharmacological treatments (e.g., SSRIs for depression).
• Cognitive Neuroscience Integration: Combines cognitive and biological approaches for comprehensive understanding.

Issues and Debates

Free Will vs. Determinism

• Biological approach is strongly deterministic, emphasizing biological processes over personal control.

Nature vs. Nurture

• Emphasizes nature through genetic/biological factors but acknowledges environmental influences (brain plasticity).

Holism vs. Reductionism

• Often criticized as reductionist for simplifying behaviors to biological explanations.

Idiographic vs. Nomothetic

• Adopts a nomothetic approach, seeking general laws applicable to all humans.

Scientific Research Methods

• Utilizes scientific, empirical methods like neuroimaging and genetic testing, enhancing credibility.

Timeline

1. The Voyage of the Beagle (1805-1836)
2. Harlow (1848): Phineas Gage brain injury case study.
3. Darwin (1859): Published "On the Origin of Species."
4. Jane Goodall (1957): Began primate study.
5. Edward Wilson (1975): Published "Sociobiology."
6. Tooby and Cosmides (1992): "The Psychological Foundations of Culture."

References

• Bouchard, T. J., & McGue, M. (1981).
• Darwin, C. (1859).
• Harlow, J. M. (1848).
• Tooby, J., & Cosmides, L. (1992).
• Wilson, E. (1975).