Maria Jimenez (UNED)
The upsurge in social science experimentation that has taken place in the last two decades is partly (if not mainly) based on the idea that experiments have a privileged access to causal identification and inference. In the case of laboratory experiments with humans, though, a pervasive potential threat to intelligibility of results for inferential purposes comes in the form of demand effects of experimentation. This way, reactivity, or the phenomenon by which subjects tend to modify their behavior in virtue of their being studied upon, is often cited as one of the most important difficulties involved in social scientific experiments, and yet, there is to date a persistent conceptual muddle when dealing with the many dimensions of reactivity. This paper offers a conceptual framework to reactivity that draws on an interventionist approach to causality. The approach allows us to offer an unambiguous definition of reactivity and distinguishes it from placebo effects. Further, it allows us to distinguish between benign and malign forms of the phenomenon, depending on whether reactivity constitutes a danger to the validity of the causal inferences drawn from experimental data.
