Pollyanna gets a bad rap. Even Mary Pickford, the silent movie star who bought the rights to the 1913 bestseller about an uber-optimistic orphan, was said to detest the girl and story.

Pollyanna uses the game to spread good cheer among townspeople including a self-pitying invalid, a grouchy old miser, a poor orphan, a fire-and-brimstone preacher, and more.

Pollyanna even spawned her own word, a faintly derogatory expression about someone who won’t deal with reality. “An excessively or persistently optimistic person,” says the dictionary.

Pollyanna, the story of an orphan girl with a relentless and very contagious positive attitude to life, was written by Eleanor H. Porter about a century ago. It was an enormous success. The same ...

The new study, published in the Proceedings of the National Academy of Sciences looked at the Pollyanna principal, the theory that people have a tendency to use positive words more than negative ones.