Genetic and Environmental Analysis for Verbal and Non-verbal Intelligence of 5-6 Years Twins: An Intervention Study

Author: Annu and Bimla Dhanda

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Abstract

The genetic variations accounted for around 60-70% in verbal and non-verbal intelligence of twins during early childhood. Intelligence is mental ability of a person towards planning, reasoning, problem-solving, abstract thinking, quick learning and learning through experiences. The main aim of twin investigation was to analyse the genetic and environmental variations in verbal and non-verbal intelligence of twins to assess the impact of intervention on intelligence of twins. The study was planned to examine the how much of variations in verbal and non-verbal intelligence of twins from the age 5-6 years due to genetic and environmental factors and assess the impact of intervention programme on intelligence of twins. Twin research was conducted in Bhiwani and Hisar district of Haryana state. Twins with age group of 5-6 years was selected from villages of Bhiwani district and Hisar district. Intelligence of twins was examined with help of Stanford Binet Intelligence Scale (Terman and Merrill 1960), whereas home environment of twins was measured by using the Home Observation for Measurement of the Environment (HOME) (Caldwell and Bradley, 1984). Results of present twin study revealed that the significant difference in mean values was observed on age 5-6 years for non-verbal intelligence of twins in Bhiwani and Hisar district on the basis of standard test. The findings on heritability estimates showed that the influence of genetic material on verbal and non-verbal intelligence level of twins was more than the environment in both districts. The contribution of genetics was more on verbal intelligence of twins than non-verbal intelligence of twins. Home environment of twins improve the intellectual abilities of twins in early childhood period. The findings of twin study revealed that identical twins were more correlated with each other as compared to fraternal twins for their both verbal and non-verbal intelligence. The result showed that significant increase in intelligence level of twins due to several activities related to intelligence provided through the intervention programme. Intervention programme was also responsible to improve the intelligence of twins.

Keywords

Verbal intelligence, Non-verbal intelligence, Genetics, Environment and Twins

Conclusion

Twin research concluded as the genetic and environmental variation in verbal and non-verbal intelligence of twins during early childhood, more influenced by genetic propensities than environmental factors. The genes are more responsible for variations in verbal intelligence of twins than non-verbal intelligence of twins. The impact of genetic material was more as compared to the environmental circumstances. The more similarity in verbal and non-verbal intelligence of twins was in monozygotic twins than dizygotic twins. The home environmental circumstances significantly associated with intelligence of twins in early years of life. The composite home-environmental settings are responsible for enhancement of the intelligence level of twins. Intervention programme was enhanced the intelligence of twins in both Bhiwani and Hisar District.

References

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How to cite this article

Annu and Bimla Dhanda (2023). Genetic and Environmental Analysis for Verbal and Non-verbal Intelligence of 5-6 Years Twins: An Intervention Study. Biological Forum – An International Journal, 15(5): 39-44.