Nature Nurture debate

• Nature-nurture debate


  The extent to which behaviour is due to genetics or characteristics
• Heredity


  Genetic transmission from one person to another in mental and physical characteristics
• Environment

  Non genetic influence on behaviour
• Interactionist approach


  Development of behaviour in terms of factors
• Bowlby


  Baby attachment type is due to parental love
• Kagan


  Baby's innate personality is due to attachment relationships
• Nature creates nurture

  Environmental and hereditary factors interact
• Diathesis-stress model

  Behaviour is caused by environmental or biological diathesis expressed with a biological or environmental trigger
• Epigenetics


  Change in genetics without changing the genes. Process happens throughout our lives, caused by interaction with the environment. Our experiences leave a mark in our DNA. It's inherited influences
• Descartes argued all human characteristics are innate (determined by biological factors)
• Locks argued mind is a blank slate at birth then shaped by environment
• Measuring nature and nurture

  1. Degree of which individuals are similar in a particular trait presented as correlation coefficient (called concordance)

  2. Concordance provides estimate to which trait is inherited (heritability)
• Heritability


  Proportionate differences between individuals in a population with regards to a particular trait due to genetic variation
• 1% heritability means genes contribute nothing to individual differences, 10% means genes are the only reason for individual differences
• Half of personal intelligence is determined by genetics and half by environmental factors
• Evaluation

  1. Use of adoption studies to determine environmental or genetic influence

  2. Meta-analysis by Rhee and Waldman found genetic influence of 41% of variance in aggression

  3. Approach may be misguided as suggested by Plomin

  4. Support for Epigenetics as reported by Susser and Lin

  5. Real-world application as put by Nestadt et al
• If adopted children are similar to adoptive parents

  They have environmental influence
• If adopted children are similar to biological parents

  They have genetic factors
• Women who became pregnant during famine

  Had low birth weight babies, developing into schizophrenia babies when they grow up
• High heritability doesn't mean it's inevitable that the individual will develop the disorder


  People with high genetic risk to OCD can receive advice about likely developing it and how to prevent it