Abstract

Phenotypic plasticity, or an organism’s capacity to change its phenotype in response to environmental variation, is a pervasive—perhaps even ubiquitous—feature of the biological world. Accordingly, plasticity research suggests serious implications for biological theory, including evolutionary theory. The theoretical implications of plasticity have growing support from empirical literature documenting the range, extent, and adaptiveness of plasticity. However, the empirical evidence for particular instances of plasticity has still not been adequately scrutinized by biologists or philosophers. After reviewing some important conceptual and theoretical background information, this paper synthesizes some past discussions of the methodology of plasticity studies and provides some novel methodological guidance for plasticity researchers. My conclusion is that not all plasticity studies should carry the same weight: there are patterns we can identify in the features of such studies that should contribute to their credibility. In particular, I argue that some types of organisms and some types of plastic phenotypes are more conducive to the empirical study of plasticity than others.