This chapter describes the savanna theory of happiness, which posits that it may not be only the consequences of a given situation in the current environment that affect individuals’ happiness but also what its consequences would have been in the ancestral environment. The theory further suggests that the effect of such ancestral consequences on happiness is stronger among less intelligent individuals than among more intelligent individuals. Consistent with the theory, being an ethnic minority, living in urban areas, and socializing with friends less frequently all reduce happiness, but the effects of these conditions are significantly stronger among less intelligent individuals than among more intelligent individuals. The theory can further explain why some individuals suffer from seasonal affective disorder (SAD) and why women’s level of happiness has steadily declined in the United States in the past half-century.</p
