nature vs nurture debate

what is the debate

• Nature vs Nurture is a debate concerned with the extent to which aspects of behaviour are a product of inherited or acquired characteristics/behaviours.

  • The debate is about the relative contribution of each influence is on behaviour.

• Nature = inherited influences or heredity

• Nurture = influence of experience and environment

nativism

The term used to describe a stance that agrees with the nature side of the debate. It was introduced by Rene Descartes (1596-1650), who suggested that the human soul was born with an understanding of certain key concepts, predispositions, and pre-programmed behaviour.

Physical and psychological factors are both determined by biological factors and are all innate

empiricism

The term used to suggest that we are born without any innate mechanisms. John Locke argued that we are born a ‘tabula rasa’ (a blank slate) and that we learn from our experiences with the environment.

Important feature of behaviourism

heredity

The process by which traits are passed from parents to their offspring, usually referring to genetic inheritance. The genetic transmission of mental and physical characteristics from one generation to another.

environment

Any influence on human behaviour that is not genetic. This may include cultural and historical influences at a societal level.

Lerner identified that there are different levels to environments - prenatal such as smoking or music can affect a foetus but more generally development is influenced postnatally

epigenetics

This refers to a change in our genetic activity without changing the genes themselves. It is a process that happens throughout life and is caused by interaction with the environment. Aspects of our lifestyle or events we encounter (from smoking and diet to trauma and war) leave 'marks' on our DNA (genes), which switch genes on or off. This explains why factors such as smoking have a lifelong influence even after you stop - they have changed the way your genes will be expressed.

May also influence the genetic codes of our children - introduces the life experience of previous generations into the debate

concordance rates

The degree to which two people are similar on a particular trait. It can be represented by a correlation coefficient. This provides an estimate about the extent to which a trait is inherited - called heritability. Heritability is the proportion of differences between individuals in a population, with regards to a particular trait, that is due to genetic variation.

interactionist

The view that processes of nature and nurture work together rather than in opposition. Researchers study how nature and nurture interact and influence each other.

diathesis-stress model

This is one conceptualisation of the interactionist approach that allows us to explain behaviours such as mental illness using the model of biological/genetic vulnerability (diathesis) interacting with an environmental influence (stressor) in order to produce a behaviour.

topic links

• Topic link - SZ

  • Genetic explanation of SZ supports the idea that SZ is inherited

  • It is polygenic and different genetic variations have been linked to an increased risk of developing

  • Thus, people are born with genetic predisposition to schizophrenia, demonstrating a biological basis for this mental disorder

• Topic link - phobias

  • Two process model by Mowrer

  • Phobias are learnt through the environment

  • Classical conditioning can explain the initiation of phobias and operant conditioning can explain the maintenance of phobias through negative reinforcement

• Topic link - attachment types

  • Bowlby argues that this is due to warmth of parental love which is environmental

  • Kagan says it is due to baby's innate temperament which is biological

  • So both environment and heredity may interact

• Topic link - OCD

  • Someone might have genetic vulnerability for OCD but will not develop the disorder without a psychological trigger

strength 1 of nature-nurture debate

• One strength of the nature-nurture debate is that it has real-world applications.

• Research suggests that OCD is a highly heritable mental disorder (high genetic heritability).

  • For example, Nestadt et al. (2010) put the heritability rate at .76 which suggests OCD is mostly down to nature.

  • Understanding of the nature-nurture debate can inform genetic counselling because it is important to understand that high heritability does not mean it is inevitable that the individual will go on to develop the disorder.

• This means that people who have a high genetic risk of OCD because of their family background can receive advice about the likelihood of developing the disorder and how they might prevent this (e.g., learn to manage stress).

• This shows that the debate is not just a theoretical one but that it is important, at a practical level, to understand the interaction between nature and nurture.

strength 2 - of nature-nurture debate

• Another strength of research into the nature-nurture debate is the use of adoption studies.

• Adoption studies are useful because they separate the competing influences of nature and nurture.

  • If adopted children are found to be more similar to their adoptive parents, this suggests the environment is the bigger influence.

  • Whereas, if adopted children are more similar to their biological parents (no influence on their environment), then genetic factors are presumed to dominate.

  • A meta-analysis of adoption studies by Rhee and Waldman (2002) found that genetic influences accounted for 41% of the variance in aggression.

• However, research suggests that this approach may be misguided, that nature and nurture are not two entities that can simply be pulled apart.

  • According to Plomin (1994) people create their own 'nurture’ by actively selecting environments that are appropriate for their 'nature’.

  • Thus, a naturally aggressive child is likely to feel more comfortable with children who show similar behaviours and will choose their environment accordingly.

  • Then, their chosen companions further influence their development.

  • Plomin refers to this as niche picking.

• This suggests that it may be impossible to try to separate nature and nurture influences on a child’s behaviour. Despite this, adoption studies are a key tool for attempting to disentangle these influences.

weakness of debate 1

• One limitation is that nature and nurture cannot be separated - some conditions show both genetic and environmental influence.

• An example of this is the disorder phenylketonuria, an inherited/genetic disorder that prevents the amino acid phenylalanine being metabolised, resulting in brain damage.

  • If the condition is detected at birth, however, an infant can be given a diet devoid of phenylalanine and thus brain damage is averted.

  • If prevention can be achieved through environmental manipulation, it cannot be said as to whether this condition is due to nature or nurture.

• Furthermore, there is research which shows how nurture can affect nature.

  • Maguire et al.'s (2000) study of London taxi drivers showed that the region of their brains associated with spatial memory (hippocampi) was bigger than in controls due to their spatial navigation experience.

  • The taxi drivers were not born this way; rather, their hippocampi had responded to increased use. 

• This suggests that nature and nurture must not be studied independently and instead is always better explained in terms of an interactionist approach.

weakness of debate 2

• Another limitation is that if nature and nurture are looked at independently it could lead to unethical implications.

• Nativists suggest that 'anatomy is destiny' in that our genetic make-up determines our characteristics and behaviour, with little environmental input.

  • This extreme determinist stance has led to controversy, such as linking ethnicity, genetics and intelligence and the application of eugenic policies that aim to increase ‘desirable’ traits and ‘decrease ‘undesirable’ ones, often through discriminatory and unethical methods, such as forced sterilisation, leading to human right abuses.

• In contrast - but also controversially - empiricists suggest that any behaviour can be changed by altering environmental conditions.

  • Behaviour shaping, a behaviourist concept, has had practical application in therapy.

  • Desirable behaviours are selectively reinforced, and undesirable behaviours are punished or ignored.

  • Carried to an extreme this could lead to complete social control by the state for the 'good' of everyone.

    • Fully controlled through environmental conditioning - behaviourist techniques like reinforcement and punishment can be misused for social control

• This suggests that we must take an interactionist approach to the nature-nurture debate as taking an extreme stance on either side of the debate could lead to serious unethical consequences.

  • Safer and more balanced