There are three science-backed components of real optimism that can be learned: possibility, agency and resilience.

For years, scientists believed that our temperament was hardwired by the time we reached adulthood. We were told that if you were a “natural-born pessimist,” that was simply your biological destiny.

Add Yahoo as a preferred source to see more of our stories on Google. (Amr Bo Shanab via Getty Images) For decades, heart health advice has focused on a few key pillars: Eat healthily, exercise, don't ...