Count your blessings this Thanksgiving. It's good for you.

While it seems pretty obvious that gratitude is a positive emotion, psychologists for decades rarely delved into the science of giving thanks. But in the last several years they have, learning in many experiments that it is one of humanity's most powerful emotions. It makes you happier and can change your attitude about life, like an emotional reset button.

Especially in hard times, like these.

What is the brain chemistry behind this and what are the best ways of inducing it?

(READ the AP article in the Mercury News)