Casting effects of early-life experiences in life history perspective is not news to this audience, but for the fields of developmental psychology and child development it challenges the standard developmental canon. Rather than regarding the ways of developing that we in the West value as how nature intended us to develop–and their opposite as evidence of dysfunction, dysregulation and disorder–what needs to be appreciated is that the long history of our species exposure to adverse childhood experiences (ACES) has adaptively shaped how children respond to such developmental environments. Evidence that this is so comes from evolutionary inspired work showing that early-life adversity often accelerates sexual development as indicated by earlier timing of puberty. This is a discovery that standard developmental thinking did not anticipate, nor is it able to explain, but clearly reveals how fitness considerations have shaped human development even in the earliest years of life. A second insight afforded by putting on evolutionary lens takes the form of the differential-susceptibility hypothesis. This stipulates that children should vary in their developmental plasticity, that is, susceptibility to environmental influences; and this is because the future is and has always been inherently uncertain, meaning that throughout human history fitness-undermining mismatches have occurred between what early-life has shaped individuals to expect and what they eventually encounter as they develop. Evidence documenting this claim, even within families, will also be presented.
