Owls might look smart, but night owls really are

Here's the conclusion from an interesting research article:

The Savanna–IQ Interaction Hypothesis suggests that more intelligent individuals may be more likely to acquire and espouse evolutionarily novel values and preferences than less intelligent individuals, while general intelligence may have no effect on the acquisition and espousal of evolutionarily familiar values and preferences. An earlier study (Kanazawa, 2010) has shown that more intelligent individuals are more likely to be liberal and atheist, and more intelligent men (but not women) are more likely to value sexual exclusivity, than their less intelligent counterparts. In this paper, we have extended the Hypothesis to circadian rhythms.

While studies show that there is some genetic component to individuals’ circadian rhythms (Hur, 2007), heritability of these phenotypes is far from 1.0 and thus there is room for individual choices and decisions. Survey of ethnographies of traditional societies shows that routine nocturnal activities were probably rare in the ancestral environment and are thus evolutionarily novel. The Savanna–IQ Interaction Hypothesis therefore predicts that more intelligent individuals are more likely to be nocturnal than less intelligent individuals.

Our analysis of Add Health data supports the prediction derived from the Hypothesis. Net of age, sex, race, marital status, parental status, education, earnings, religion, whether one is currently a student and the number of hours worked per week, childhood IQ significantly increases nocturnal behavior in early adulthood. More intelligent children are more likely to grow up to be nocturnal adults who go to bed late and wake up late on both weekdays and weekends (Kanazawa, S., Perina, K. Why night owls are more intelligent. Personality and Individual Differences. 2009).