The literature on early experience and child development emphasizes the role of the immediate social environment, in particular the parental and sociocultural factors that shape parents' caregiving behaviors. But another, less prominent literature considers adaptive-evolutionary factors that inform and modify the behaviors of parent and child to achieve optimal reproductive and survival outcomes for each (e.g., Blurton Jones, 1993; Chisholm, 1996; Hewlett & Lamb, 2002). LeVine (1989) has noted that these cultural and adaptive-evolutionary contexts of caregiving may conflict, and that even though parents strive to provide children with competencies that are fitted to their specific culture, environments with a high risk of child morbidity may prompt them to prioritize child survival over socialization. As human behavioral ecologists have pointed out, parents are further constrained by the finite resources of time and energy that they must carefully allocate among parenting and other critical activities, such as subsistence (Hill & Hurtado, 1996). Thus their care of any given child, or children in general, cannot be understood without reference to the limits of and competing claims on their resources.

In view of these considerations, complete understanding of parenting behavior should integrate dynamics among biology, evolutionary ecology, and culture. From a bioevolutionary perspective, reproductively significant behaviors such as parenting should represent solutions to adaptive problems posed by recurring conditions that have influenced reproductive fitness. An example of such an adaptive solution is the capacity of infant distress signals (fussing and crying) to evoke a response from caregivers.