Not wasted on the young: Childhood, trait complexes & human behavioral ecology

Hypotheses about the evolution of multi-trait organismal features often encounter trade-offs between the precision and historical relevance of tests performed in actualistic contexts. That is, highly precise tests aimed at discriminating between competing hypotheses often incur a risk of explanatory misalignment with the historical phenomenon they target. We illustrate this via a discussion of the evolution of childhood. We argue childhood is a trait complex, consisting of multiple, diverse components: patterns of growth, feeding strategies, staggered skill acquisition, and social dependence. The potential of their independent evolution bears important consequences for the evolutionary significance of tests probing the adaptive benefits of childhood in contemporary foraging communities. Via 'isolation-testing' such investigations aim for precision at the cost of historical relevance in a potentially serious way. We suggest that integrative investigations relying on the timing and context of components' evolution, emphasizing historical relevance, frame evolutionary hypotheses more reliably than the emphasis on precise tests currently common, thus bearing a higher explanatory potential.