Emodiversity: Robust Predictor of Outcomes or Statistical Artifact?

Brown, N. J. L., & Coyne, J. C. (2017). Emodiversity: Robust Predictor of Outcomes or Statistical Artifact? Journal of Experimental Psychology. General. DOI: 10.1037/xge0000330

Abstract: This article examines the concept of emodiversity, put forward by Quoidbach et al. (2014) as a novel source of information about “the health of the human emotional ecosystem” (p. 2057). Quoidbach et al. drew an analogy between emodiversity as a desirable property of a person’s emotional make-up and biological diversity as a desirable property of an ecosystem. They claimed that emodiversity was an independent predictor of better mental and physical health outcomes in two large-scale studies. Here, we show that Quoidbach et al.’s construct of emodiversity suffers from several theoretical and practical deficiencies, which make these authors’ use of Shannon’s (1948) entropy formula to measure emodiversity highly questionable. Our reanalysis of Quoidbach et al.’s two studies shows that the apparently substantial effects that these authors reported are likely due to a failure to conduct appropriate hierarchical regression in one case, and to suppression effects in the other. It appears that Quoidbach et al.’s claims about emodiversity may reduce to little more than a set of computational and statistical artifacts.