Guess what personality trait is most associated with longevity? If you said "happiness," "optimism" or "healthy relationships," I don't blame you. Those characteristics all seem like they'd make for a long, fulfilling life. The real answer will surprise you:
It's conscientiousness, according to a study that followed subjects for 80 (!) years, conducted by psychology professors Howard Friedman, Ph.D., and Leslie Martin, Ph.D. People who are organized, prudent and persistent are apparently outliving the rest of us. Huh.
But if you think about it, this makes sense: Conscientious people are thoughtful about how they live, and they embrace the notions of moderation and balance. They might challenge themselves to get out for a run a few times a week, but they don't go too far--pushing themselves to exhaustion or to overtrain. Same goes for how they eat--probably healthfully but not obsessively (and if they eat a scoop of ice cream, they're likely not beating themselves up about how they "blew it" then polishing off the entire gallon). They're probably measured and mindful about how they pick friends and romantic partners, and in the way they balance work and family and free time. In other words, they're tuned in to living well, but they give themselves wiggle room to make mistakes. Sounds like a recipe for a long and healthy life to me!
Genes also play a part in longevity, of course, but less than you may think: they account for about a third of the puzzle. The rest is comprised of chance and lifestyle. That last piece--lifestyle--is where conscientiousness comes in, and it's something we can all aspire to.
Dr. Catherine Birndorf is a psychiatrist specializing in women's health, founding director of the Payne Whitney Women's Program at NewYork-Presbyterian Hospital in NYC, co-author of The Nine Rooms of Happiness and SELF's Happiness Expert.