Happy as a lark: morning-type younger and older adults are higher in positive affect.

A literature on young adults reports that morning-type individuals, or "larks," report higher levels of positive affect compared with evening-type individuals, or "owls" (Clark, Watson, & Leeka, 1989; Hasler et al., 2010). Morning types are relatively rare among young adults but frequent among older adults (May & Hasher, 1998; Mecacci et al., 1986), and here we report on the association between chronotype and affect in a large sample of healthy younger and older adults. Overall, older adults reported higher levels of positive affect than younger adults, with both younger and older morning types reporting higher levels of positive affect and subjective health than age mates who scored lower on morningness. Morningness partially mediated the association between age and positive affect, suggesting that greater morningness tendencies among older adults may contribute to their improved well-being relative to younger adults.