other researchers, who have compiled data on fraternal and identical twins, submit that 50 percent of baseline happiness is genetic, 10 percent is due to life circumstances such as finances, marital status, and appearance, and 40 percent is due to attitude, which is under a person's direct control. To provide people with a way to monitor and improve attitude, some scientists have been working on a "happiness trainer.'' This trainer provides brainwave feedback to users so they can learn to induce a positive of mind. the session begins with a pleasing film geared to making a person feel good. As brainwaves move into a happier mode, the film image grows larger. This provides the feedback necessary to demonstrate how to maintain these pleasure-inducing brainwaves. Learning this new skill may require both practice and persistence, although the inventors believe that the inherent rewards make it a highly worthwhile endeavor.