Nature vs Nurture

• Environment


  Everything that is outside our body, including people, events and the physical world. Any influence on behaviour which is non-genetic
• Lerner's levels of the environment

  Ranged from pre-natal experiences to post-natal experiences
• Nature


  Any influence on behaviour which is genetic e.g. the action of genes, neurochemistry, neurotransmitters and neurological structures
• Heredity


  The process by which traits are passed from parents to their offspring, usually referring to genetic inheritance
• Heritability coefficient


  Can be used to quantify the extent to which a characteristic has a genetic basis
• Intelligence appears to have a heritability coefficient of 0.5, so the influences of nature and nurture are equal
• Interactionist approach


  The view that the processes of nature and nurture work together rather than in opposition
• Nature-nurture debate


  The argument as to whether a person's development is mainly due to their genes or to environmental influences
• Most researchers accept that behaviour is a product of the interaction between nature and nurture
• Genetic explanations


  The more closely related two individuals are, the more likely that they will develop the same behaviours
• The concordance rate for schizophrenia is 40% for MZ twins and 7% for DZ twins
• Concordance rates for MZ twins are not 100%, despite being genetically identical, suggesting that nurture and the environment also plays a significant role in development
• Evolutionary explanations


  Behaviours which promote survival will be naturally selected
• Bowlby's attachment theory


  Attachment was adaptive as it meant an infant was more likely to be protected due to displaying social releasers and features of infant-caregiver interactions
• Behaviourism


  Assumes that all behaviour can be explained in terms of experience alone, using classical and operant conditioning
• Social learning theory


  Behaviour is acquired indirectly through operant and classical conditioning but also by directly through vicarious reinforcement
• Double blind theory of schizophrenia

  Schizophrenia develops in children who frequently receive contradictory messages from parents, preventing the child from developing an internal consistent construction of reality
• Diathesis-Stress Model


  A diathesis is a biological vulnerability, but the expression of the gene depends on experience in the form of a stressor which triggers the condition
• Tienari et al (2004) found that children without a genetic risk but raised in a family climate characterised by tension and a lack of empathy did not develop schizophrenia, while children with a genetic risk and who experienced the same family climate did go on to develop schizophrenia
• Maguire et al study of London taxi drivers showed that the region of their brains with spatial memory was bigger than in controls, because the hippocampi had responded this way
• Epigenetics


  Refers to the material in each cell that acts like a switch to turn genes on or off, and these switches are passed on when the DNA is replicated
• Caspi et al (2002) found that 12% of men with less MAOA gene expression had experienced maltreatment when they were babies but were responsible for 44% of crimes
• Constructivism


  An individual's 'nature' would determine their 'nurture' through niche-picking or niche-building