What the nature and nurture debate asks

1. The debate asks how far your behaviour comes from what you inherited and how far it comes from what has happened to you.

The term nature

1. Nature is the influence of inherited biology on behaviour, such as your genes and the brain chemistry they affect.
2. A nature explanation says the cause was already in the person before any experience acted on them.

The term nurture

1. Nurture is the influence of experience on behaviour, including upbringing, learning, relationships and the wider society around you.
2. A nurture explanation says the cause lies in experience, so a different environment would have produced a different outcome.

The nature side of depression and addiction

1. The genetic explanation of depression argues that inherited genes affecting serotonin raise a person's risk of becoming depressed.
   1. The 5-HTT gene studied by Caspi is the serotonin transporter gene, so it is exactly this kind of inherited influence.
2. The genetic explanation of addiction argues that inherited differences in brain chemistry make some people more likely to become addicted.
3. Both sit on the nature side, because in each the raised risk is carried into the situation before any experience is added.

The nurture side of depression and addiction

1. The cognitive theory of depression argues that depression grows out of negative and unhelpful ways of thinking that develop through experience.
2. The learning theory of addiction argues that addiction is acquired through classical conditioning, operant conditioning and social learning.
   1. Each of those three routes needs the environment to supply something, whether that is the pairing, the reward or the model.
3. Both sit on the nurture side, because they place the cause in what happened to the person rather than in what they inherited.

What Caspi et al. (2003) adds to the debate

1. Caspi is the study that turns this from a two-sided argument into an interaction.
2. Carriers of the short 5-HTT allele showed much stronger links between stressful life events and depression, yet the allele on its own did not produce depression.
3. Short-allele carriers had not experienced any more stressful events than everyone else, so the gene changed sensitivity to stress rather than exposure to it.
4. Childhood maltreatment predicted adult depression only in short-allele carriers, which is nurture having an effect that depends on nature.
5. Caspi therefore supports an interactionist account, often called diathesis-stress, in which an inherited vulnerability needs an environmental trigger before the problem appears.

What Young (2007) adds to the debate

1. Young found that 114 clients with internet addiction improved through CBT and were still managing six months later.
2. If changing thoughts and behaviour changes the problem, then learning and experience are doing real work in keeping the addiction going.
3. That is evidence on the nurture side, although the missing control group means it is not decisive.

Turning this into marks

1. Define both terms accurately and then apply them to the person in the scenario.
2. Name Caspi for the interaction and Young for the treatment evidence, because a debate answer with no research in it has nothing to weigh.
3. The mark most often lost is arguing only one side when the question names both.