Research in the area of infant development has endless facets of investigation. No one facet of research is more important than another, and all of the findings work in a synchronous fashion to facilitate our understanding of child development. Research on child development has proliferated across the centuries. Infant characteristics like attention, digestion, and behavior are among the areas studied. The research findings in these and many other areas have deepened our understanding of how infants respond to their environments, and to the people who care for them. The findings from past research have also led to changes in strategies for interacting with infants in the medical, educational, and parenting realms.