Improving the Early Childhood Social Assistance National Program PI-SUAS/Criança Feliz: Impact Evaluation of the Home Visits

Early childhood, the period from conception to six years of age, is a crucial phase of human development, marked by rapid growth and skills acquisition. The brain undergoes accelerated development and is highly receptive to stimuli and experiences, which leave lasting impressions and influence the individual's future.

The early years of the 21st century have been marked by a large body of scientific evidence on child development, demonstrating that the environment induces epigenetic, immunological, and psychosocial adaptations. These adaptations begin with conception and produce lifelong effects. In other words, factors such as the quality of the physical and social environment in which the child lives; access to healthcare; interaction and engagement from caregivers; cognitive and emotional stimulation; proper nutrition; and exposure to chronic toxic stress and adversity have a profound and lasting impact on the child's life and future.

Brain plasticity refers to the central nervous system's ability to reorganize itself in response to external stimuli, through the development of new synapses, changes in gene expression, among other processes. Studies have shown that this ability is greatest early in life and declines over time. In addition to the concept of brain plasticity, science has established that complex skills are built upon fundamental ones. Thus, a child's development is a process of maturation and interaction with the environment, resulting in sequential progression of perceptual, motor, cognitive, language, socioemotional, and self-regulation skills.

All this evidence reinforces the importance of ensuring a healthy start to life and protecting children from harmful and detrimental factors to their development. While this period of life is filled with opportunities for learning and growth, it is also a time of great vulnerability to the effects of adversity.

A nurturing environment-characterized by a home setting that is attentive to the child's health and nutritional needs, caregiver responsiveness, and emotional support during early childhood, especially in the first two years of life-protects the child and their development from the damaging effects associated with poor socioeconomic conditions. Failing to provide such conditions and stimuli results in impaired full development of the child, with serious individual consequences such as chronic diseases in adulthood, lower academic achievement, and reduced labor market participation and income throughout adult life. On a societal level, the consequences include increased public health costs, the persistence and worsening of social inequality, and the loss of human capital.