Nature VS Nurture

• The nature-nurture debate is an argument about the extent to which behaviours are due to the influence of nature (biology) or nurture (environment).
• Biological psychologists include learning in their theories:

  • Recognise the interaction between biological processes (driven by inherited genes) and environmental factors.
  • Early trauma and deprivation can impact brain development, leading to vulnerabilities in mental health later in life.
  • Understanding of brain plasticity.
  • Diathesis-Stress model.
• Behaviourists include biology in their theories:

  • Learning theories.
  • Primary reinforces (eg need for food and sex) are intrinsic and biological.
  • Secondary reinforcers are not innately satisfying but become valued as they are often linked to satisfying primary reinforces.
• The nativists - Rene Descartes

  • Nature.
  • Descartes believed in the concept of the mind possessing innate ideas at birth. He argues such ideas form the basis of all knowledge and understanding. Although he was unfamiliar with the concept of DNA, he argued innate knowledge is transmitted biologically through heredity.
• The empiricist - John Locke:

  • Nurture.
  • Argues knowledge comes from experience and observation rather then being inborn. He described the mind as a blank state ('tabula rasa') which is shaped and filled through understandings. He claimed all knowledge and understanding are gained through the environment.
• Psychological theories closer to nature view:

  • Genetic explanation for OCD - Individuals may inherit vulnerability, possibly due to faulty SERT gene affecting serotonin transport.
  • MAOA gene for aggression - 'Warrior' gene variation found in 1/3 of Western men, linked to aggressive behaviour.
  • Genetic basis of schizophrenia - Hereditary due to close family members being at increased risks when related to a person with the disorder.
  • Bowbly's monotropic theory - Babies born with innate need to form attachments for survival.
  • Evolutionary theory - Mate selection and aggression is inherited.
• Psychological theories closer to the nurture view:

  • Cupboard love theory of attachment - Babies form attachments to mothers because they provide food for them (learned association).
  • Ainsworth's strange situation - Secure and insecure attachment styles develop from mother's sensitive responsiveness.
  • Behaviourist theories on phobias - Phobias are acquired through associative learning in traumatic experiences.
  • Social learning theory - Behaviour is learned through observing and imitating models.
  • Cognitive theories - Schemas are acquires through learning and experience.
• Interactionism is the view that both nature and nurture work together rather than in opposition. The diathesis-stress model is an example of this.
• Discussion points:

  • Psychodynamics is a clear example of interactionism. Freud argues that children undergo psychosexual developmental stages at specific ages, which are biologically driven (nature), an innate process. However, he emphasised the interaction of these innate stages with the child's unique life experiences at each stage (nurture). This combination shapes adult personalities and anxieties.
• Discussion points:

  • Concordance rates of mental health conditions in MZ twins and DZ twins. Gottesman found 48% in MZ and 17% in DZ for schizophrenia. Nesdat found 68% in MZ and 31% in DZ for OCD. The absence of 100% concordance would be expected if the conditions were purely genetic, suggesting both genes and the environment play a role in this.
• Discussion points:

  • Taking a dichotomous view of behaviour as solely innate or environmental can benefit the treatment of disorders. For example, assuming OCD is purely genetic led to the development of SSRI's in treatment. However, the most effective treatment is SSRI with CBT, indicating the advantages of an interactional treatment approach which considers both nature and nurture.
• Discussion points:

  • Accepting behaviour as primarily influenced by nature or nurture has implications, particularly in mental illness and legal contexts. Viewing mental illness as being due to environmental factors empowers sufferers to modify their thought processes, as opposed to more passive role suggested by a purely biological explanation. In the legal system, it has been argued that if aggressive behaviour is mainly biologically driven, it could result in a reduced sentence, under the argument they are not responsible for their inherited genes.
• Discussion points:

  • Nature and nurture interact through epigenetic modification. DNA has chemical marks that influence how DNA is expressed so certain genes can be switched on or off. This collection of markers is our epigenome. Environmental experiences can alter the epigenome, especially in children; positive life experiences like supportive relationships and a stimulating environment, and negative experiences such as exposure to toxins or stress can alter how genes are expressed in brain cells, either negatively or positively influencing behaviour in later life.
• Strengths of the nature-nurture debate:

  • Diathesis-stress model - Tienari studied 145 Finnish adoptees with mothers who had schizophrenia and were matched with a sample of 158 adoptees without this risk. After 12 years, 14 developed schizophrenia (11 from the high risk group). Children without a genetic risk but raised in a family climate characterised by tension and a lack of empathy did not develop SZ. However, children with a genetic risk and who experienced the same family climate did develop SZ, illustrating how being raised in a “healthy adoptive family” has a protective effect.
• Strengths of the nature-nurture debate:

  • Constructivism — Plomin suggested that an individual’s ‘nature’ would determine their ‘nurture’ through niche-picking or niche-building. For example, a naturally aggressive child would be more likely to play with and befriend other aggressive children. This in turn would increase the aggressiveness of the child. Therefore, the idea of constructivism further emphasises the multi-layered relationship between nature and nurture.