Developmental theories often posit that changes in children's early psychological characteristics will affect much later psychological, social, and economic outcomes. However, tests of these theories frequently yield results that are consistent with plausible alternative theories that posit a much smaller causal role for earlier levels of these psychological characteristics. Our paper explores this issue with empirical tests of skill building theories, which predict that early boosts to simpler skills (e.g., numeracy or literacy) or behaviors (e.g, anti-social behavior or executive functions) support the long-term development of more sophisticated skills or behaviors. Substantial longitudinal associations between academic or socioemotional skills measured early and then later in childhood or adolescence are often taken as support of these skill-building processes. Using the example of skill-building in mathematics, we argue that longitudinal correlations, even if adjusted for an extensive set of baseline covariates, constitute an insufficiently risky test of skill-building theories. We first show that experimental manipulation of early math skills generates much smaller effects on later math achievement than the nonexperimental literature has suggested. We then conduct falsification tests that show puzzlingly high cross-domain associations between early math and later literacy achievement. Finally, we show that a skill-building model positing a combination of unmeasured stable factors and skillbuilding processes is able to reproduce the pattern of experimental impacts on children's mathematics achievement. Implications for developmental theories, methods, and practice are discussed.Keywords early childhood; interventions; skill-building; cognitive development; education Developmental theories often posit that changes in children's early psychological characteristics will affect their much later psychological, social, and economic outcomes. Such theories include skill-building theories (e.g., Baroody, 1987;Stanovich, 1986;Cunha & Heckman, 2007), theories of the life-course development of psychopathology (e.g., Moffitt, 1993), theories that posit reciprocal effects between children and their environments Corresponding Author: Drew H. Bailey, School of Education, 3200 Education, University of California, Irvine, Irvine, CA 92697-5500, dhbailey@uci.edu.
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Author Manuscript Author ManuscriptAuthor Manuscript Author Manuscript (e.g., Scarr & McCartney, 1983), and theories of early critical periods in children's social and cognitive development (Fraley and Roisman, 2015).Tests of these theories are often conducted by estimating correlations between important outcomes and children's early psychological characteristics that have been adjusted by statistical controls for variables that might affect both early and later child characteristics. These findings are given varying degrees of causal interpretation. A cautious, yet superficial, alternative app...