Individual differences in development of children can be attributed to

Modern developmental psychology recognizes that individual differences arise from the complex interplay between heredity (genetic factors) and environment (experiences, culture, nurturing). This nature-nurture interaction is bidirectional and dynamic—genes influence how individuals respond to environments, and environments influence gene expression (epigenetics). Neither factor alone can explain developmental variations. The interactionist view is supported by extensive research across behavioral genetics, neuroscience, and developmental psychology.