• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Critically consider the role of genetic factors in the development of measured intelligence.

Extracts from this document...


Sophie Parslow                28/04/07

Critically consider the role of genetic factors in the

 development of measured intelligence.

Genetic factors are a major influence on the development of measured intelligence. However, extensive research suggests that genetic factors alone cannot account for a person’s intelligence. Research evidence suggests that a person’s intelligence isn’t ‘fixed’ from birth, but environmental and social factors can cause an increase in intelligence.

The importance of genetic factors in intelligence is exemplified in family resemblance studies. This involves examining the correlation of intelligence test scores among people who vary in genetic similarity. If genetic factors influence IQ then the closer the genetic relationship between two people, then the greater the correspondence rate (concordance) between their IQ’s should be. In Bouchard and Mcgue’s worldwide review of 111 studies, they found the closer the genetic relationship between individuals the higher the correspondence of IQ scores.  For example the correlation for cousins (who share 12.5 % of their genes) is weaker than that for parents and offspring who share 50 % of their genes. The strongest Correlation is for Monozygotic twins (identical twins) who share the same genes.Therefore,these findings suggest that genetic factors play a key role in measured intelligence. However, the main

...read more.


Furthermore research into adoption studies seems to prove genetics play a fundamental role in influencing intelligence. Adoption studies are useful in proving that genetic factors influence intelligence because children share half their genes with their biological parents but none of their environment, and their environment with adoptive parents but none of their genes. Musinger found that the correlation of IQ score for adopted children and biological parents was 0.48 compared to 0.19 for adopted children and adoptive parents. Therefore, in this study biological factors seem more important than environmental factors in determining intelligence. Moreover, Plomin found that IQ’s of adopted children and their unrelated siblings showed a weak correlation.  Thus proving that even though the children shared the same environment,  their intelligence differed because of their genetic differences.  

However a problem of adoption studies is assessing the similarity between biological parents and adoptive parent’s environments. Research by Scarr and Weinberg proves that when the environments of the biological and adoptive parents are very different a substantial change in IQ score can be observed. Scarr and Weinberg carried out a study of 101 white families that where above average in intelligence, income, and social class who adopted black children. If genetics are  the only

...read more.


In conclusion measured intelligence can be recognised as an interaction between genetic and environmental factors. Genes do not fix intelligence; instead they provide the basis of intellect. Environmental factors build on genetic intelligence, and as extensive research proves a stimulating environment can lead to an increase of IQ scores. The correlation between IQ scores and genetic similarity exemplifies that intelligence is mainly biologically based. However Intelligence is highly changeable and can be increased due to environmental factors. If both environmental and genetic factors influence intelligence then this causes the problem of how much each contributes. Heritability refers to how much a characteristic is determined by genetic factors within a particular population at a particular time. The heriabilty estimate of genetic factors in IQ is 80%  however more recently that has been decreased to 50/60%(Bouchard and Segal).  This makes is difficult to distinguish whether it is environmental factors of genetic factors that determine intelligence because they are closely linked. Moreover Bee’s research proves that children from higher educated, middle class families have children with higher IQ’s, however this could be because of environmental factors or genetic factors or both.

...read more.

This student written piece of work is one of many that can be found in our GCSE IQ Correlation section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE IQ Correlation essays

  1. This experiment will show that there is a significant positive correlation between males and ...

    would have a profound effect on accepting or rejecting my hypotheses. In my study I have no background information on any of the participants or any indication of what sort of psychological state they may be in. For a self-esteem study such as this one a detailed initial questionnaire would

  2. A typical intelligence test asks a variety of questions, many of which are of ...

    "intelligence is what intelligence tests measure" (1969, cited in Howe, 1997). Although most definitions seem to have a similarity, the meaning of intelligence can vary over time and through cultures. It was once thought that intelligence was all down to a persons ability with spelling and arithmetic, whereas in the

  1. HYPOTHESIS Blonde girls are more intelligent than non blonde girls. Blonde girls that ...

    As a result of this, according to this set of data I interpret that although there is very little difference between the two sets of values Blonde Girls are more consistent with their IQ and because their box plot is more to the right I believe that this graph shows that Blonde Girls are more intelligent than Non Blondes.

  2. What role does intelligence play in earning potential?

    But what is the overall affect of intelligence on one's earnings in future? The essay is going to establish the correlation between the intelligence level and the earning potential of individual, by examining psychological researches' data, analyzing statistics, case examples and surveys.

  1. Maths IQ correlations

    + 102 = 78 7 Range = 102 - 32 = 70 Band B, stratified samples are = 62, 93, 88, 77, 39, 39, 92 Mean = 62 + 93 + 88 + 77 + 39 + 39 + 92 = 70 7 Range = 93 - 39 = 54

  2. Maths Coursework on IQ

    from each year group 7, 8 and 9. From the resulting data, I will draw up graphs and continue my project further. The following pages show the sampled names and important data on them; I will now divide these students into 5 groups according to their IQ, showing both their IQ and their Key Stage results.

  1. Predicted grades given by subject teachers at the time of Yellis.

    expect no correlation, because both prediction are based on an element of ability. But this is the student ability at the time, of Yellis; this could change positively or negatively over the time before the final gcse exam. C But if there was not this distribution if it looked like D1 then the relation ship would be rank ????

  2. Mayfield Maths Coursework

    weight is 62.5 then you will have 11 sick days which is showing the more you weigh the more number of sick days. Median of weight: (E2:E17) = 63.5 Median of sick days: (F2:F17) = 12 Interquaritle range: To find the interquartile range of weight: Lower quartile range on weight: 1/4(N+1)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work