Excerpt: In the last few years, psychologists and researchers have been digging up hard data on a question previously left to philosophers: What makes us happy? Researchers like the father-son team Ed Diener and Robert Biswas-Diener, Stanford psychologist Sonja Lyubomirsky, and ethicist Stephen Post have studied people all over the world to find out how things like money, attitude, culture, memory, health, altruism, and our day-to-day habits affect our well-being. The emerging field of positive psychology is bursting with new findings that suggest your actions can have a significant effect on your happiness and satisfaction with life. Here are 10 scientifically proven strategies for getting happy.