For example, Early Head Start, a comprehensive two-generational program for children under age 3 and their families, has been shown to promote cognitive, language, and social and emotional development.41 The success of Early Head Start illustrates that high-quality services for infants and toddlers-far too rare in the United Ststes today-have a long-lasting and positive impact on children’s development, learning abilities, and capacity to regulate their emotions.42