Extraversion predicts longer survival in gorillas: an 18-year longitudinal study.

Personality plays an important role in determining human health and risk of earlier death. However, the mechanisms underlying those associations remain unknown. We moved away from testing hypotheses rooted in the activities of modern humans, by testing whether these associations are ancestral and one side of a trade-off between fitness costs and benefits. We examined personality predictors of survival in 283 captive western lowland gorillas (Gorilla gorilla gorilla) followed for 18 years. We found that of four gorilla personality dimensions--dominance, extraversion, neuroticism and agreeableness--extraversion was associated with longer survival. This effect could not be explained by demographic information or husbandry practices. These findings suggest that understanding how extraversion and other personality domains influence longevity requires investigating the evolutionary bases of this association in nonhuman primates and other species.