Health varies markedly with social circumstances. While we are still without a comprehensive account of the mechanisms which underlie this variation, it is clear that psychological factors are involved and that key pathways may prove to be psychophysiological. Thus, social psychophysiological research of the kind illustrated in this Special Issue is ideally placed to help unravel some of the mechanisms by which social circumstances impact on health. Nevertheless, the success of this sort of social psychophysiological enterprise most likely depends on reconceptualizing psychophysiological reactivity as a situational, or psychological exposure, concept rather than as an individual difference concept. This shifts the research goal from one of identifying individuals at risk for disease to identifying the psychological exposures that put individuals and groups at risk.