Thinking Clearly About Correlations and Causation: Graphical Causal Models for Observational Data

Lower social class (or socioeconomic status) is associated with fewer resources, greater exposure to threat, and a reduced sense of personal control. Given these life circumstances, one might expect lower class individuals to engage in less prosocial behavior, prioritizing self-interest over the welfare of others. The authors hypothesized, by contrast, that lower class individuals orient to the welfare of others as a means to adapt to their more hostile environments and that this orientation gives rise to greater prosocial behavior. Across 4 studies, lower class individuals proved to be more generous (Study 1), charitable (Study 2), trusting (Study 3), and helpful (Study 4) compared with their upper class counterparts. Mediator and moderator data showed that lower class individuals acted in a more prosocial fashion because of a greater commitment to egalitarian values and feelings of compassion. Implications for social class, prosocial behavior, and economic inequality are discussed.

Psychologists increasingly recommend experimental analysis of mediation. This is a step in the right direction because mediation analyses based on nonexperimental data are likely to be biased and because experiments, in principle, provide a sound basis for causal inference. But even experiments cannot overcome certain threats to inference that arise chiefly or exclusively in the context of mediation analysis-threats that have received little attention in psychology. The authors describe 3 of these threats and suggest ways to improve the exposition and design of mediation tests. Their conclusion is that inference about mediators is far more difficult than previous research suggests and is best tackled by an experimental research program that is specifically designed to address the challenges of mediation analysis.