How You Sleep Is Who You Are

'Being a morning person or a night owl doesn’t just determine when you start or end your workday; your internal clock may help define your psychology as well. A Spanish researcher found that our preference for engaging in activities earlier or later in the day shapes both our perceptions and our interactions. The author gave personality tests to 360 university students, whom he describes as a “proper sample,” noting that the circadian rhythms of students “are not much under the influence of time schedules and social patterns.” (Despite the occasional all-nighter, students presumably can follow their preferred sleep schedules more easily than working adults can.) His results offer new evidence that morning and evening types think differently. Early risers prefer to gather knowledge from concrete information. They reach conclusions through logic and analysis. Night owls are more imaginative and open to unconventional ideas, preferring the unknown and favoring intuitive leaps on their way to reaching conclusions. Social behavior diverges as well: Morning people are more likely to be self-controlled and exhibit “upstanding” conduct; they respect authority, are more formal, and take greater pains to make a good impression. (Earlier research also suggests that they are less likely to hold radical political opinions.) Evening people, by contrast, are “independent” and “nonconforming,” and more reluctant to listen to authority—which suggests that teachers may have several reasons to prefer those students who wake up in time for class.'
—from a study entitled “Morning and Evening Types: Exploring Their Personality Styles,” performed by a Spanish psychologist, and referenced in The Atlantic Monthly.