The ratio between positive and negative affect and flourishing mental health across adulthood.

Using data from a 30-day diary study with 239 adults (81 young, 81 middle-aged, and 77 older adults), this study examined whether a specific ratio between positive and negative affect distinguished individuals with different mental health status and especially flourishing from non-flourishing individuals. In addition, the study addressed whether there were age differences in the positivity ratio when daily affect data were used, and whether the proposed critical positivity ratio of 2.9 discriminated equally well between individuals with different mental health status across the adult lifespan. Findings showed that the ratio of positive to negative affect differed across adulthood such that age was associated with an increasing preponderance of positive to negative affect. The positivity ratio was also associated with mental health status in the hypothesized direction; higher positivity ratios were associated with better mental health. Finally, although the data supported the notion of a positivity ratio of 2.9 as a 'critical value' in young adulthood, this value did not equally well discriminate the mental health status of middle-aged and older adults.