Nature Nurture Debate

Objectives

• Aims to be able to summarise the nature nurture debate.

• Become Familiar with conclusions and political implications of Burt’s and Jensen’s work on IQ

• Understand the idea of Canalised development

• Understand the long-term conclusions of Rutter’s work on Rumanian refugees

Nature or Nurture?

• The essence of the debate is that people differ from each other in lots of ways – physically, height, eye colour, in terms of intelligence, behaviour and so on.

• How do we explain this?

There have been two main explanations for this.

• The Nativists who emphasis heredity and nature

• Empiricists – who emphasis experience and learning.

Twin studies

• Share the same genes

• If separated will have had different experiences (environments)

• Scientists can measure the relative contribution of environment or genes on the attainment of the child

• Often used to study heritability of IQ (intelligent quotient)

Research on IQ

• Cyril Burt arguing that selection was necessary due to the innate nature of intelligence.

• As a consequence, the eleven plus exam was introduced which was largely compiled of IQ tests?

• Those who passed the tests went on to grammar schools and were prepared for higher education, whilst those who failed went to academically inferior secondary modern schools.

Research on IQ

• Arthur Jensen (1969) suggested that genetic differences were the cause of the consistently lower IQ scores observed in non-white racial groups.

• In practice, this meant that little could be done to improve the intelligence of those children labelled as having inferior intelligence.

Problems with these studies

• Such arguments have been used to explain why compensatory education programmes have little long-term effect, diverting attention away from consideration of other potential causes of low IQ scores.

Social policies that reflected these findings

• 7000 people were sterilised in Virginia because they had low IQ’s.

• In 1912 IQ’s were used to restrict immigrants to the USA.

Problems with the research

• Test scores from children and adults in the middle and upper classes tend to be higher than those of children and adults in the lower socioeconomic classes.

• White children tend to receive higher scores than ethnic minorities.

• Males receive systematically higher scores on some tests and systematically lower scores on other tests than females.

Empiricist Research

• Recent Empiricist research• The environment, in the form of light falling on the retina

was fundamental to the development of visual ability. • Later work by Hubel and Wiesel (1959) and Blakemore

(1969) showed that although specific neural receptors may be present at birth, their functioning depends upon the correct environmental stimulation within a critical period of time.

• Blakemore (1969) had also demonstrated with kittens reared in an environment of vertical lines that receptors specialised for responding to horizontal stimuli failed to develop, making the kittens functionally blind for these stimuli.

Learning or maturation?

• A boy of three does not have a beard. When the boy reaches puberty and a beard starts to grow, he has already spent many years learning or observing that men grow beards. Has he therefore learned to grow one himself?

Learning or maturation?

• A girl of four has a musical family but she cannot yet play the piano.

• By the age of 16, she can play more competently than her brother or sister, both of whom are older.

• Did she have an innate talent for piano playing?

Instinct:

• Instinctive behaviour is observed in all normal healthy members of a' species.

• Thus, it is little influenced by the environment. • The genetic instructions provide detailed

information for the development of instinctive behaviour, and only quite general environmental input (such as is necessary for healthy growth) is needed for its expression.

Maturation:

• Maturation refers to the emergence of instinctive behaviour patterns at a particular point in development.

• The genetic instructions facilitate the expression of certain behaviour patterns when a certain growth point is reached or a certain time period has elapsed.

Learning:

• Learning refers to the influence of specific environmental information on behaviour. Within a wide range of variation, the way an animal behaves depends on what it learns from the environment. Thus, individuals of a species may differ considerably in their learnt behaviour patterns.

Studies of Birds

• Chaffinches reared alone produce only a very basic kind of song.

• It seems they need the stimulation and learning of other chaffinches to produce proper bird song.

• Chaffinches can only learn from other chaffinches if fostered by another species they will not learn the other song.

• Chaffinch song is stable, so for example the songs of chaffinches which were introduced into New Zealand in 1862 and South Africa in 1900 are very similar.

Bird Studies

• However Bullfinches the song is largely learned and there are few constraints.

• For example if fostered by canaries they will learn canary song.

• Are you a chaffinch or a bullfinch?

Canalised Behaviour

Attainment of Rumanian Children

Results – an example of canalised development

• The latest-placed adoptees (in the 24-42 month group) exhibited low-average cognitive scores as a group.

• These children had long-term difficulties. As a group they showed lower cognitive scores and a general developmental impairment in comparison with those children who had been adopted earlier.

• Despite the fact that they had been adopted by supportive and caring families, the early deprivation continued to have a negative influence on their emotional adjustment at 6 years.

• While there was some improvement, unfortunately there was no differential catch-up for these later-placed adoptees between the ages of 4 and 6 even though the length of time with their adoptive families was by now longer than the period of time spent in the Romanian orphanages.

• These findings suggest that early deprivation rather than the time spent in the adoptive home beyond a period of 2 years seemed to be the key factor in explaining the extent of their cognitive and physical developmental catch-up.

Conclusions

• If children are rescued from extreme deprivation at earlier than 2 years of age there is evidence that they will demonstrate considerable resilience and catch-up.

• Additionally the catch-up of the immediate adoption period is maintained and not 'washed out' provided that the adoptive family is caring and supportive.

• At the same time, deprivation is associated with impairment and there are long-term difficulties for those children who experience severe deprivation for more than the first two years of their lives

My Overall Conclusions

• Neither extreme position will adequately explain the complexity of human behaviour and development.

• Genetic or Nativist explanations may mean that there is inadequate scrutiny or criticism of the environmental factors, and can be accused of being linked to conservative social policies that do not redress the social inequalities that people may experience.

• There may be particular times when the ball of development can be more easily shifted down a desirable track.

• That does not mean that we should not try to help all individuals to attain their fullest potential.

Questions

• What are your views about research that for examples tries to identify the gay or criminal gene?

• What importance may the idea of canalised development have for example in relation to children brought up in extreme deprivation?

• Which position reflects the core values that you consider important in Social Care?