Abstract

This chapter analyzes the causal dimension to multi-level selection theory. Particular attention is paid to the idea that direct selection at one hierarchical level may generate, as a side effect, a character-fitness covariance at a different level, and thus the _appearance_ of direct selection at that level. Such ‘cross-level’ byproducts lie at the heart of the levels of selection problem and show that Price's equation cannot be an infallible guide to determining the level(s) at which selection is acting. The nature of cross-level byproducts in MLS1 and MLS2 is examined, and the statistical technique known as contextual analysis, which can be used to detect cross-level byproducts, is explored.