Parenting and Child Development

Our species is characterized by extraordinary biological success. We have successfully populated all corners of the planet, calling a wide array of habitats in wildly different ecosystems ‘home’. This remarkable success is not only a consequence of our distinct life history characteristics, but is intricately tied to our ability to cooperate with one another. The evolution of human motherhood tells a different story from that of our closest living relatives, the great apes. We have a comparatively long stage of dependence, yet begin to reproduce earlier, and human mothers wean their infants before they are nutritionally independent. This allows them to resume ovulation sooner and have subsequent offspring more rapidly, effectively shortening the interbirth interval (IBI). This shortened IBI allows women to give birth to new infants while simultaneously providing care for existing children, leading to greater reproductive success than their ape counterparts. Because human children are very energetically expensive, it begs the question – how did early hominin mothers do it? The answer is that they did it with help. They relied on assistance extending far beyond the pair bond, or even nuclear families, and were assisted by members of their social group of all ages, including from children. Given that children have a relatively long time to learn how to be a functional adult, social learning further highlights the utility of cooperative ties because adaptive information can accrue over many generations. Children can effectively assist in the care and maintenance of themselves as well as other children – making them an integral part of the human cooperative breeding matrix. In order to understand the history of our species, as it relates to family formation and child development, we must first consider how the distinct reproductive challenges faced by our ancestors were associated with the larger social contexts in which they evolved.