Genetic and Environmental Diversity in Verbal and Non-verbal Intelligence of Twins from 3-5 years

Abstract:

Genes accounted for 50-66% of the verbal and nonverbal intelligence of twins. Intelligence is considered the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experiences. The objective of the present twin study was to assess the diversity of genetic material and environmental factors in the verbal and non-verbal intelligence of twins. A twin study was conducted in two districts, namely, Bhiwani and Hisar of Haryana state. A sample of 100 pairs of twins in the age groups of 3-5 years was attained in villages of Bhiwani district and Hisar district. The intelligence of twins was assessed with help of the Stanford Binet Intelligence Scale [1], whereas the home environment of twins was assessed by using the Home Observation for Measurement of the Environment (HOME) [2]. Results of the present twin study indicated that a highly significant difference in mean values was observed in age of twins for verbal and non-verbal intelligence of twins with the age group 4-5 years of twins of Bhiwani and Hisar district on the basis of the standard test. The findings on heritability estimates showed that the influence of genetics on verbal and non-verbal intelligence level of twins was more than the environment in both districts. The non-verbal intelligence of twins was more influenced by genetic factors as compared to verbal intelligence. The home environment of twins especially learning stimulation in home settings improved the intelligence of twins in early years of life.