Beyond cumulative risk: Distinguishing harshness and unpredictability as determinants of parenting and early life history strategy.

Drawing on life history theory, Ellis and associates' (2009) recent across- and within-species analysis of ecological effects on reproductive development highlighted two fundamental dimensions of environmental variation and influence: harshness and unpredictability. To evaluate the unique contributions of these factors, the authors of present article examined data from a national sample 1364 mothers and their children participating in the NICHD Study of Early Child Care and Youth Development. Harshness was operationalized as income-to-needs ratio in the first 5 years of life; unpredictability was indexed by residential changes, paternal transitions, and parental job changes during this same period. Here the…