1. Debate: Nature and Nurture
The degree to which human behaviour is determined by genetics/biology (nature) or learned through interacting with the environment (nurture)

2. Aims of lesson
To understand what is meant by the nature-nurture debate and to identify the main assumptions .
To be able to describe at least 1 study which supports nature, and 1 study to support nurture.
To be able to identify the perspectives/ approaches relevant to the debate.

3. Nature Behaviour is caused by innate characteristics :
The physiological/biological characteristics we are born with.
Behaviour is therefore determined by biology.
Determinist view- suggests all behaviour is determined by hereditary factors:
Inherited characteristics, or genetic make-up we are born with.
The nature side of the debate suggests behaviour is cause by characteristics we are born with- the innate characterisitcs, which are usually physiological or biological. People behave the way they do because they are animals who act in accordance with their animal instincts (innate characteristics) and are determined by their biology.
These characteristics are inherited from our ancestors, and form our genetic makeup

4. Nature All possible behaviours are said to be present from conception.
Genes provide the blueprint for all behaviours; some present from birth, others pre-programmed to emerge with age.
Is a developmental approach:
E.g. Piaget: children’s thought processes change at predetermined age-related stages
changes in age are related to changes in behaviour.
The nature argument suggests that our genes pre-programmed all our behaviours. All possible behaviours are present from conception however whilst some are expressed from birth others are pre-programmed to emerge as we mature. The nature side of the debate is therefore a developmental approach, behaviour change is caused by age and maturation.

5. Nurture
An individuals behaviour is determined by the environment- the things people teach them, the things they observe, and because of the different situations they are in.
Also a determinist view- proposes all human behaviour is the result of interactions with the environment.
On the other hand, the nature side of the debate suggests that people behave the way they do because they are determined by the things other people teach them, the things they observe, and because of the different situations they are in.
Like the nature side, the nurture side is also a determinist view as it proposes all human behaviour is the result of interactions with the environment.

6. Nurture Behaviourist theories are nurture theories:
- Behaviour is shaped by interactions with the environment.
Born an empty vessel- waiting to be filled up by experiences gained from environmental interaction.
No limit to what they can achieve:
-Depends on quality of external influences and NOT genes.
The quality of the environment is KEY:
-You can become anything provided the environment is right.

7. Support for Nature
Identical genes exist in Identical Twins- Monozygotic (MZ) twins share 100% of their genes.
Fraternal Twins- Dyzygotic Twins (DZ), share 50% of their genes.
Genetic effects can therefore be shown when the correlations within each group is compared with the correlations between each group.
This can be added to the correlations found with other relatives. Parents share 50% of genes, cousins share 12.5%.
Twin and adoption studies are used to show how much of a behaviour or trait is due to genetics or due to the environment. Identical twins have identical twins- this means they share 100% of their genes, where as non-identical fraternal twins share only half of their genes- 50%.
Genetic effects can therefore be shown when the correlations within each group is compared with the correlations between each group. This can be added to the correlations found with other relatives as parents share 50% of their genes, siblings share 25%, and cousins share 12.5%.
Adoptive children are included in analysis to help separate the effects of growing up in shared environments. Adopted children’s similarity to their biological parents reflects genetic similarity and eliminates environmental factors. Adopted children with adopted parent similarity reflects environmental similarity and eliminates genetic similarity.
Variations between identical twins must be the consequences of the shared environmental influences.

8. Support for Nature
Genetic basis of Schizophrenia (Gottesman & Shields, 1976) - A review of twin and adoption studies into schizophrenia between 1967 and In adoption studies: compared biological parents and siblings and adoptive parents and siblings. - In twin studies: compared concordance rates (how often both twins were diagnosed with schizophrenia) for monozygotic (identical) and dyzygotic (non-identical) twins.
In order to determine whether schizophrenia, a serious mental illness has a genetic link, Gottesman and shields carried out a compreshensive review of twin and adoption studies. The concordance rates – how often both twins were diagnosed with schizophrenia was compared for monozygotic- identical, and dyzgotic- non-identical twins. In adoption studies, biological parents and siblings and adoptive parents and siblings were compared to separate out the contribution of genetics and environment on the development of the disorder.
Video

9. Support for Nature Results
- Adoption studies found increased incidence of schizophrenia in adopted children with a schizophrenic biological parent.
- ‘Normal’ children fostered to a schizophrenic parent and adoptive parents of schizophrenic children showed little evidence of schizophrenia.
- Twin studies found higher concordance rate for schizophrenia in MZ twins (58%) than DZ twins (12%).
Conclusion
Significant genetic input into the onset of schizophrenia. Genes responsible for predisposing a person to schizophrenia.
All adoption studies found an increased incidence of schizophrenia in adopted children with a schizophrenic biological parent, whereas normal children fostered to schizophrenic parents and adoptive parents of schizophrenic children showed little evidence of schizophrenia.
Twin studies found a higher concordance rate for schizophrenia in monozygotic- or identical twins, than dyzygotic- or non-identical twins. Significantly there was a concordance rate of 58% in monozygotic twins which means that if one twin had schizophrenia there was a 58% chance the other would have it, compared against a 12% chance in non-identical dyzgotic twins.
Both these comparisons indicate that there is a significant genetic input into the onset of schizophrenia, but with concordance rates less than 100% there must be some interaction with the environment. Certain genes appear to predispose a person to schizophrenia.

10. Support for Nature IQ scores
-Plomin (1988) studied MZ and DZ twins reared together and apart and found that I.Q. has an overall heritability of genetics are responsible for about 68% of the variation in I.Q.
-MZ twins reared apart have I.Q. scores which correlate at about 0.74, or 74%.
Evaluation point
However, variations between identical twins must
be due to environmental influences.
Twin studies have also been used to show the heritability of IQ. Plomin found that when the IQ scores of identical and non-identical twins living both together or apart were studied the overall heritability of IQ was about 0.68, or another way, 68% of IQ was due to genetic influences.
When only identical twins who were raised apart were studied the correlation increased to 0.74, meaning twins who share 100% of their DNA but grow up in different environments still have IQ scores that are 74% similar- the genetic influence is greater than the environmental influence.
Whilst genetics seem to be the biggest influence on IQ the environment must also have an influence, in identical twins 26% of the difference in scores must be due to environmental factors

11. Support for Nurture – Little Albert
Classical conditioning of fear- phobia acquisition: ‘little Albert’ (Watson & Raynor, 1920)
-Before the study little Albert showed no sign of fear response in any situation.
Session 1: Aged 11 months, Albert was presented with a rat. Each time he reached for the rat a steel bar was hit.
1st time= he jumped + fell forward nd time= he began to whimper
Session 2: after 5 paired presentations, Albert reacted to the rat alone by immediately crying, turning, and crawling away quickly.
On the side of nurture, it is argued that behaviour can be a result of exposure to certain situations and environments.
A case study on one child ‘Little Albert’, under controlled laboratory conditions was carried out to see if it is possible to induce a fear of a previously unfeared object through classical conditioning.
Before the experiment little albert showed no fear response to any objects including a white rat. In the first session, when aged 11 months, little albert was presented with a rat, but each time he reached for it a steel bar was hit. The 1st time this happened he jumped and fell forward, the 2nd time he began to cry. In session 2, after 5 rat-bar presentations, Albert reacted to the rat alone by immediately crying, leaning and crawling away quickly.

12. Support for Nurture
Session 3: Albert returned to see if the fear had transferred. - Presentation of toy blocks (neutral stimulus) = playing - Presentation of the rat followed by a rabbit, dog, fur-coat, Watson’s hair and a Santa Claus = –ve responses of crying, moving away from stimulus and crawling. Session 4: steel bar + rat, steel bar+ rabbit, steel bar+ dog. Fear response was pronounced in all. Session 5: 1 month later Albert continued to show fear reactions to all stimuli. Transference of the fear had been made to similar objects.
In session 3 Albert was tested to see if the fear had been transferred to other previously unfeared, but similar looking objects. When give toy blocks Albert played happily, however when the rat was presented and was immediately followed by either a rabbit, a dog, a fur-coat, Watson’s hair, or a santa clause beard Albert showed negative responses of crying and moving away from the stimulus.
Session 4 tool this future, and presented the new similar stimuli paired with the steel bar, as originally done with the rat. Albert showed a definite pronounced fear response to all.
One month later Albert was brought back to see if the fear response had subsided, but albert continued to show fear reactions to all similar stimuli. Transference of the fear had been made to similar objects. Albert unfortunately was never returned to be desensitised to the objects!

13. Support for Nurture Conclusion
- By session 2, after 5 paired presentations the conditioning of fear was evident: is possible to condition fear through classical conditioning.
- By sessions 3 & 4, transference of the fear had been made to similar objects.
- By session 5, time had not removed the fear response.
Provides evidence that the environment can be manipulated to create a phobic response & behavioural change.
(See key study: A2 OCR textbook p.115)

14. Support for Nurture- Milgram

15. Can you think of any other studies that show the effect a situation can have on behaviour?
Milgram? Bandura- Bobo? Pilliavin- helping behaviour?

16. Nature Nurture Interaction
Behaviour is often a result of the interaction between nature AND nurture.
An individuals characteristics may elicit particular responses in other people e.g.
Temprament: how active, responsive or emotional an infant is influences in part determines their caregivers responses.
Gender: people tend to react differently to boys and girls due to expectations of masculine and feminine characteristics.
Aggression: Displaying aggressive behaviour create particular responses from other people.
It is more often accepted that behaviour is a result of the interaction between nature and nurture, or biology and the environment.
One view is that people may construct or contribute to their own environments. For example, an individual’s characteristics (which may be innate) such as temperament, gender, or level of aggression, may ellicit particular responses from other people, which may in turn influence the individual’s behaviour.
Others take a view which states that an individuals genes are seen as setting upper and lower limits for their potential behaviour. Where within these limits an individual’s behaviour falls may be determined by the environment.

17. Nature Nurture Interaction Evidence
Rutter and Rutter (1993) Aggression hostility
- Described how aggressive children think and behave in ways that lead other children to respond to them in a hostile manner.
-This then reinforces the antisocial child’s view of the world. Thus, aggressive children tend to experience aggressive environments partly because they elicit aggressive responses.
Rutter and Rutter thought that it was too simplistic to just say that children are either born aggressive or learn aggression, and instead suggested that children pay exhibit aggressive characteristics which in turn causes people around them to respond in a hostile or aggressive manner. This aggressive response then acts to reinforce the child’s aggressive behaviour, beliefs and tendencies.
They suggest that aggressive children tend to experience aggressive environments partly because they elicit aggressive responses in others.

18. Nature Nurture Interaction
Maguire et al. (2000)- Taxi driver study
- Structural MRI scans of the brains of licensed London taxi drivers were compared with controls who did not drive taxis.
- Hippocampal volume correlated with the amount of time spent as a taxi driver
- The posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects.
- The posterior hippocampus stores a spatial representation of the environment and can expand regionally in people with a high dependence on navigational skills.
Whilst some behaviours can be traced to physiology research does indicate that the environment can create brain changes.
Research by Maguire et al. Found that the structure of the hippocampus in the brains of taxi drivers change as a result of their environment- which suggests than an interaction between nature and nurture affects brain structure.
See AS Psychology textbook: pp.68

19. Nature Nurture Interaction
Maguire et al. Conclusion
- It appears the brain has the capacity for plasticity (the ability to change)- the structure of the brain can alter in response to environmental demands.

20. Supporting Approaches & Perspectives
Supporting NATURE
Supporting NURTURE
Physiological
Social
Learning Approach
(behaviourism)
Psychodynamic
Cognitive
The physiological approach focuses on biological influences on behaviour, so is therefore influenced by nature.
Much social research takes the Nurture side of the debate: showing that behaviour is influenced by the social environment. Research by Piliavin et al. Demonstrated that it was not the nature of the passengers that influenced whether they helped, but the situation of the victim that motivated helping behaviour.

21. Problems with Nature-Nurture Debate
It is reductionist
It is deterministic
It is difficult to control variables
Determinism: The ‘nature’ view of psychology is a determinist one- it suggests behaviour is determined by hereditary factors (e.g. IQ).
Links to other debates

22. Applications Nature Nurture
Drug therapies can be developed to treat behavioural or psychological problems that have a physiological origin.
E.g. SSRI’s can be used to treat depression, Ritalin- ADHD.
Nurture
If behaviour is susceptible to environmental influences we need to consider how we adapt our environment.
E.g. To promote helping behaviour, enhance learning, reduce aggression and decrease criminality.
BUT- where does learning fit?? Nature like Piaget, or nurture
like Skinner?
A key application of the nature debate is the development of drug thereapies to target and treat behavioural and psychological problems that have a physiological origin. For example, SSRI’s can be used to treat depression and anxiety disorders, whilst Ritalin can be used to help ADHD.
You can use the AS and A2 textbooks to find studies and examples to support and expand on the applications of the nature-nurture debate. The studies can also be used to reinforce important evaluative points, for example- with learning, both nature and nurture offer practical applications to understanding. Whilst developmentalists such as Piaget suggest that a childs development happens at predetermined age-related stages, behaviourists such as Skinner disagree and instead propose that children learn through imitation and reinforcement. Therefore, to best understand and help facilitate child development it would be important to understand what they are capable of at certain stages of development, but how best to help them reach their maximum potential.

23. Summary
Nature: behaviour is caused by characteristics we are born with e.g. genetic, physiological.
Nurture: behaviour is shaped through interactions with the environment.
Research supporting nature: language development, IQ scores, predisposition to schizophrenia etc.
Research supporting nurture: fear acquisition, effect of the environment on behaviour.

24. Summary cont...
Nature-nurture interaction: Temperament and gender can influence other peoples behaviour.
Exposure to certain environmental stimuli can alter physiology e.g. Brain structure, neurochemicals.
Applications: Development of drug therapies,
adapt environments to increase helping behaviour, enhance learning etc.
Link to other debates: Determinism
Complete handout