Nature-Nurture Debate Flashcards
Environment
Everything that is outside our body, including people, events and the physical world. Any influence on behaviour which is non-genetic.
Lerner identified different ‘levels’ of the environment, which ranged from pre-natal experiences (e.g. the mother’s physiological and psychological state during preganancy) to
post-natal experiences (e.g. the socio-historical context within which the child grew up in). The view that the mind is a ‘blank slate upon which experience writes upon’ is typical of an empiricist/behaviourist approach e.g. John Locke.
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. The heritability coefficient can be used to quantify the extent to which a characteristic has a genetic basis. For example, intelligence appears to have a heritability coefficient of 0.5 (Plomin et al, 1994) and so the influences of nature and nurture are equal.
Interactionist approach
With reference to the nature-nurture debate, this is the view that the processes of nature and nurture work together rather than in opposition. They are linked in such a way that it does not make sense to separate the influences of the two.
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 a mental disorder such as schizophrenia is 40% for MZ twins and 7% for DZ twins. This illustrates how nature plays a part in contribution to the disorder. However, concordance rates for MZ twins are not 100%, despite being genetically identical. This suggests that nurture and the environment also plays a significant role in development.
Evolutionary explanations
These are based on the principle that a behaviour which promotes survival will be naturally selected e.g. running away from fire or avoiding deep water. This is because such behaviours are adaptive, so the individual is more likely to survive to adulthood and reproduce. Bowlby proposed that attachment was adaptive as it meant an infant was more likely to be protected due to displaying social releasers (innate, ‘cute’ behaviours which activates the adult mammalian attachment system) and features of infant-caregiver interactions (such as interactional synchrony and reciprocity). As such, the infant would be more likely to survive and reproduce as an adult.
Behaviourism
Behaviourists assume that all behaviour can be explained in terms of experience alone. Skinner used the concepts of classical and operant conditioning to explain learning and suggests that attachment could be explained in terms of classical conditioning where the food reduces the discomfort of hunger (negative reinforcement) and is therefore rewarding.
Social learning theory
Bandura proposed that behaviour is acquired indirectly through operant and classical conditioning but also by directly through vicarious reinforcement. He acknowledged that biology had a role to play e.g. the urge to act aggressively could be biological but the way a person learns to express anger is through environmental influences (such as through observing and imitating the methods of expression of anger displayed by the identified role models).
Other explanations
The double blind theory of schizophrenia (Bateson et al, 1956) suggests that schizophrenia develops in children who frequently receive contradictory messages from parents and these conflicting messages prevents the child from developing an internal consistent construction of reality. This is because when the child behaves incorrectly, they are punished by a withdrawal of love from their parents, leading them to believe that the world is dangerous (reflected in paranoid delusions) and confusing (reflected in disorganized thinking).
+ Diathesis-Stress Model
A diathesis is a biological vulnerability. However not everyone with these ‘candidate’ genes will develop a disorder. The expression of the gene depends on experience in the form of a stressor which triggers the condition (a diathesis). This has been illustrated by Tienari et al (20040 who studied 145 Finnish adoptees whose mothers had schizophrenia and were then matched with a sample of 158 adoptees without thisgenetic risk. The two groups were independently assessed after 12 years and of the total 303, 14 developed schizophrenia and 11 of these were 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 go on to develop SZ. This illustrates how being raised in a “healthy adoptive family” has a protective effect.
+ Nurture affects nature
Maguire et al study of london taxi drivers showed that the region of their brains with spatial memory was bigger than in controls, this is because the hippocampi had responded this way. Maguire et al. studied the brains of London taxi drivers and found a larger grey matter volume in the mid-posterior hippocampus, an area of the brain associated with spatial awareness (skills needed for taxi drivers when they are learning and completing ‘The Knowledge’ exam). There was a positive correlation between increasingly pronounced changes and an increasing length of time that individuals had been taxi drivers. This demonstrates the interactionist nature of empiricism and nativism, and gives further reason as to why the influences of the two cannot be separated.
+ Epigenetics
Refers to the material in each cell that acts like a switch to turn genes on or off e.g. DNA methylation and histone tail modification. Life experiences control these switches and these switches are passed on when the DNA is replicated semi- conservatively. This is why MZ twins may differ in weight even though they were given the same diets, due to differences in upbringing/experiences causing differences in the individual expression of genes. For example, Caspi et al (2002) assessed antisocial behaviour in 1000 participants between birth and the age of 26. The researchers found that 12% of men with less MAOA gene expression had experienced maltreatment when they were babies but were responsible for 44% of crimes. This brings a third element into the nature-nurture debate: the experiences of previous generations!
+ 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.
