Happiness has been one of the greatest subjects of fascination for philosophers, researchers, and everyday people since the beginnings of human thought and introspection. Everyone wants to know the secret to a blissful life full of happiness, and everyone seems to have a unique philosophy on what constitutes happiness and how to achieve it. The scientific quantification of happiness has been of particular interest in the field of psychology, and a 75-year study conducted at Harvard seems to have found the single most important factor for happiness. It may come as a surprise to many that professional success, job satisfaction, life-style, and wealth are only very small factors in determining someone's happiness level. The true secret to happiness is the quality, and to some extent the quantity, of our familial, romantic, and friend relationships.

The study began in 1939 and followed two groups of men, 456 poor men growing up in Boston and 268 Harvard graduates (including John F. Kennedy), for nearly 75 years. Several generations of researchers regularly checked up with these men to see where they were in life and assess their happiness levels through various factors. Despite the wide range of directions life took these diverse men, the data overwhelmingly showed that love is the biggest factor in determining happiness. No amount of money, legacy, or even physical health could ever replace the importance of strong, deep relationships with friends, family, and a significant other.

Quality relationships, measured by how open, comfortable, and interdependent you feel in a relationship, reduce stress, slow the effects of mental and physical decline, and help people cope with disappoints and trials in life. The level of satisfaction people expressed in their relationships even proved an indicator for quality of physical health later in life and loneliness proved to be as deadly a killer as smoking or alcoholism.

This study lends unique insights in life priorities. Many believe that wealth, success, or fame will make them happy and thus sacrifice the opportunity to grow closer with their family and friends. But if happiness is truly the goal, it is important to set aside quality time to strengthen your relationships and find ways to express your love and appreciation for those meaningful people in your life.

The next time life has you stressed, frazzled, or depressed, take time to step away from school, work, and other responsibilities to focus on others. Don't miss out on family dinners or spending time with friends on the weekend in pursuit of other achievements (unless you have concluded happiness is not the meaning or purpose of life, which is a valid belief held by many). Connections with the community also proved another factor in happiness, so try to become more involved in serving and getting to know those around you.

To learn more about the study and the importance of relationships to mental and physical health, check out George Valiant's book "Aging Well" or watch Robert Waldinger's TED Talk "What makes a good life? Lessons from the longest study on happiness." Also try to think about the times you are happiest; it will often go back to friends and family.