Unravelling the Socio-Economic Determinants of Intelligence in Early Childhood: A Twin Study

Abstract

The twin study design offered a unique advantage by controlling for genetic variability, allowing a clearer focus on environmental and socio-economic contributions to intelligence. This twin study was designed to explore the influence of socio-economic factors on intelligence during early childhood, a period marked by rapid intellectual and developmental changes. The research involved 150 pairs of monozygotic and dizygotic twins aged between 3 to 6 years, residing in the Bhiwani and Hisar districts of Haryana, India. This age group is especially critical, as early cognitive development sets the foundation for future learning, academic achievement, and overall mental health. Data collection was conducted through a self-structured questionnaire developed to capture a range of socio-economic indicators. The results revealed a significant association between intelligence levels and specific socio-economic variables. Notably, family size (χ2=14.52*), mother’s education (χ2=21.56*), and father’s education (χ2=12.60*) were all strongly linked to variations in intellectual functioning. Conversely, family type (χ2=4.32) and gender (χ2=0.25) did not show a statistically significant relationship with intelligence. The findings of the present twin study also suggested regional variations in the impact of socio-economic factors on early childhood intelligence. Differences between the Bhiwani and Hisar districts point to the importance of considering local contexts when designing interventions or policies. These findings support the argument that socio-economic status is not just a background factor but a key determinant of early intellectual outcomes.