This paper on "Motivated Cognition" and aging caught our eye. Researchers found that there is a developmental trend toward more strategic emotional regulation with age. Seniors are more likely to shorten their attention and memory resources toward 'negative' images, while young people were more evenly directed (and middle aged folks in-between).
Its interesting to see that the 'happy bias' was also seen with memory for images.
Being optimistic has many health, personal, career, and other long-term benefits (more research here). This developmental view of optimism is important to think about when it comes to kids. Some of the most catastropic pessimists we have ever met, are still in the first grade. When young children meet failure or setbacks, they don't have the benefit of enough lived experience to see it in context.
As for those of us who may be natural pessimists, we may have to fight biology at times, there are studies like the one below which suggest that a dominant left amygdala may be the culprit. In that study, researchers noted individual differences in how test subjects 'read' surprised faces.
Emphasizing Positive in Attention and Memory
Optimistic or Pessimistic Amygdala?