Robin Lloyd
 Special to LiveScience
 LiveScience.com

"It requires some effort to achieve a happy outlook on life, and most people don't make it."
Author and researcher Gregg Easterbrook

Psychologists have recently handed the keys to happiness to the public, but many people cling to gloomy ways out of habit, experts say.

Polls show Americans are no happier today than they were 50 years ago despite significant increases in prosperity, decreases in crime, cleaner air, larger living quarters and a better overall quality of life.

So what gives?

Happiness is 50 percent genetic, says University of Minnesota researcher David Lykken. What you do with the other half of the challenge depends largely on determination, psychologists agree. As Abraham Lincoln once said, "Most people are as happy as they make up their minds to be."