Positive affect (PA) has emerged as a key well-being facet and a powerful predictor of physical and psychological well-being. One of the strongest predictors of PA is personality, particularly neuroticism and extraversion. However, the mechanisms via which personality affects PA are not well-understood. Consistent with theories that accord cognitive factors a role in mediating the relationship between personality and outcomes, we tested whether positive automatic thoughts (PATs) mediated the relationship between neuroticism, extraversion, and PA among 199 college students (137 women, 70% White, 66% first and second year students, mean age = 24.13, SD = 8.86). Consistent with hypotheses, structural equation modeling indicated that PATs fully mediated the relationship between both neuroticism and extraversion and PA. The structural model fit the data well, χ<Superscript>2</Superscript>/df = 2.33, CFI = .96, SRMR = .07, RMSEA = .08 (90% CI: .06, .10), AIC = 172.45, and accounted for 58% of the variance in PA. An alternative model in which personality predicted PA, which in turn predicted PATs, did not provide as good a fit to the data, χ<Superscript>2</Superscript>/df = 3.03, CFI = .94, SRMR = .09, RMSEA = .10 (90% CI: .08, .12), AIC = 207.40. Models in which negative automatic thoughts (NATs) were construed as fully [χ<Superscript>2</Superscript>/df = 4.46, CFI = .95, SRMR = .08, RMSEA = .13 (90% CI: .11, .16)] or partially [χ<Superscript>2</Superscript>/df = 4.04, CFI = .96, SRMR = .06, RMSEA = .12 (90% CI: .10, .15)] mediating the relationship between neuroticism and negative affect did not provide a good fit to the data. A final model in which negative affect was tested a mediator of the relationship between neuroticism and NATs also did not fit the data well, χ<Superscript>2</Superscript>/df = 4.03, CFI = .96, SRMR = .07, RMSEA = .12 (90% CI: .10, .15). Copyright Springer Science+Business Media B.V. 2013
