Expectable Environments in Early Life.

Humans develop in the context of environmental information that can be considered either experience-expectant or experience-dependent. Though the exact timing of sensitive period closures and consequences of environmental experiences have not been well delineated, early life is a period of increased vulnerability. While some forms of care (e.g., institutional care for children; representing the absence of experience-expectant caregiving) are not present in the evolutionary history of humans, it is likely that what is considered significant hardship today may have been more typical experience-dependent environmental information in the evolutionary timescale. Thus, assumptions that threatening or neglectful experiences are unexpected for the human child may not fit well in the scope of the broader timescale of human history. We argue that it is important to consider early caregiving experiences from the context of what has been expected in our evolutionary past rather than what is expected in modern sociocultural terms.