Intelligence and Personality as Predictors of Illness and Death: How Researchers in Differential Psychology and Chronic Disease Epidemiology Are Collaborating to Understand and Address Health Inequalities

Abstract

We describe the research findings that link intelligence and personality traits with health outcomes: health behaviors, morbidity, and mortality.The former field is called cognitive epidemiology, and the latter is known as personological epidemiology.However, intelligence and personality traits are the principal research topics studied by differential psychologists, and so the combined field might be termed differential epidemiology.The importance of bringing this field to wider attention lies in the facts that: the findings overviewed here are relatively new, often known neither to researchers or practitioners; the effect sizes are on a par with better-known, traditional risk factors for illness and death, so they should be broadcast as important; mechanisms of the associations are largely unknown, so they must be explored further; and the findings have yet to be applied, so we write this to encourage diverse interested parties to consider how this might be done.To make the work accessible to as many relevant researchers, practitioners, policy makers and laypersons as possible, we first provide an overview of the basic discoveries regarding intelligence and personality.In both of these areas we describe the nature and structure of the measured phenotypes.Both are well established even though we recognize that this is not always appreciated beyond the cognoscenti.Human intelligence differences are well described by a hierarchy that includes general intelligence (g) at the pinnacle, strongly correlated broad domains of cognitive functioning at a lower level, and specific abilities at the foot.The major human differences in personality are described by five personality factor that attract wide consensus with respect to their number and nature: neuroticism, extraversion, openness, agreeableness and conscientiousness.As a foundation for the health-related findings, we provide a summary of the research which shows that intelligence and personality differences are: measured reliably and