Hope and optimism are often lumped together (as we have done here), but they are not precise synonyms. In church, most of our attention is on hope, a central aspect of the Gospel message. For scientists, the attention is reversed as optimism is an easier concept to define and study experimentally.
So what are scientists discovering? Preliminary research suggests many benefits to an optimistic disposition. It seems to correlate with better physical and emotional health, an increased ability to cope, stronger relationships, and higher levels of motivation. Additional work has been done on how to cultivate optimism. However, much less work has been done on hope whose very definition continues to be debated by philosophers and theologians.
One of the leading funders of this research, the John Templeton Foundation, has produced a summary of recent findings on optimism as well as a more detailed 35-page research review that spells out recent research on hope and optimism by psychologists, philosophers, and theologians. We summarized some of this work in a 2019 blog.