Age-related differences in trait affect: Establishing measurement invariance of the Positive and Negative Affect...

The present study examined trajectories of trait positive and trait negative affect as measured by the Positive and Negative Affect Schedule across the lifespan. Increasing levels of measurement invariance of the Positive and Negative Affect Schedule were tested across a wide age range (18-99 years of age; 10 age groups) in a large sample (N = 3,309; 65.82% women; 74.22% with a university entrance diploma; 92.23% with German as their mother tongue). Strong invariance was established so that the latent factor means of positive and negative affect could be meaningfully compared across age groups. Age had a small effect on positive affect, which showed a reversed U-shaped function with a maximum between the ages of 40 and 50. For negative affect, there was a strong cubic age effect. Specifically, negative affect decreased until about the age of 70 and then increased again. We also found a negative covariance between positive and negative affect, which first increased slightly and then decreased across age groups until becoming positive in the oldest age group. In summary, the present study supports previous findings on age trajectories of positive and negative affect but also highlights the importance of testing for measurement invariance. (PsycInfo Database Record (c) 2024 APA, all rights reserved).