I have always considered myself a happy person, even though I may not always look it thanks to inheriting my father’s furrowed brow. Are there times when I’m not happy? Of course. Do I wish I could be happier more often? Who wouldn’t? While it seems everyone is looking for the answer to the age-old question, “What’s the secret to happiness?” the better question may be, “Is it even possible to be happier?”

About half of our level of happiness is based on genes. Some people are just predisposed to be happier and more upbeat than others. But that does not mean you cannot increase your level of happiness if it does not come naturally. In fact, research has suggested that 40% of people’s happiness comes from the choices they make.

Come on, get happy

So what are the right choices for happiness? You may find inspiration from the participants in the Harvard Study of Adult Development — one of the longest-running studies on happiness.

The project has followed 724 men since they were teenagers in 1938. (Approximately 60 men, now in their 90s, are still left.) The group consisted of men from various economic and social backgrounds, from Boston’s poorest neighborhoods to Harvard undergrads. (President John F. Kennedy was even part of the original group.) Over the years, the researchers have collected all kinds of health information, and every two years they ask members questions about their lives and their mental and emotional wellness. They even interview family members.

They found that specific traits and behaviors were linked with increased levels of happiness across the entire group.

Know when to let go

As the people got older, they tended to focus more on what’s important to them, and didn’t sweat the small stuff to the degree they did when they were younger, according to the project’s director, Dr. Robert Waldinger. Other research supports this mindset, and has found that older adults are better about letting go of past failures. “They tend to realize how life is short and they are more likely to pay more attention on what makes them happy now,” says Dr. Waldinger.

You could do the same. What activities make you happy and what’s stopping you from doing them? Think back to your childhood. What did you enjoy when you were younger? Singing? Playing games? Doing certain hobbies? “When you are older you have more opportunity to return to the activities you associate with happiness,” says Dr. Waldinger. So begin that coin collection, join a choir, or play poker or bridge.

Stay connected

The Harvard Study has found a strong association between happiness and close relationships like spouses, family, friends, and social circles. “Personal connection creates mental and emotional stimulation, which are automatic mood boosters, while isolation is a mood buster,” says Dr. Waldinger. This is also an opportunity to focus on positive relationships and let go of negative people in your life, or at least minimize your interactions with them.

If you need to broaden your social life, try volunteering for a favorite cause. Odds are you will meet more like-minded people. Volunteering also is another way to boost happiness by providing a sense of purpose. In fact, a study published online May19, 2016, by BMJ Open found that this benefit was strongest among people age 45 to 80 and older. Look for volunteering opportunities in your area that match your interests.