Long, multi-year studies about the keys to happiness or success always catch my attention because they aren't common (it takes a lot of work/dedication/resources to do a longitudinal study) and because such studies get to what happens to people in the real world, over a lifetime, and not in a lab setting.

That's why the 71-year old Framingham Heart Study at Boston University caught my eye. Before you say "What's a heart study have to do with happiness?" and bail, hold tight. The study seeks to understand common factors that contribute to heart disease but in so doing it collects data on a wide variety of lifestyles factors. So much so that researchers analyzed a cross section of the study's participants, 4,739 people, and more specifically, they studied their social networks.

An interesting truth about happiness emerged, as the researchers concluded: People's happiness depends on the happiness of others with whom they are connected. Said another way, if you want to be happy, surround yourself with happy people. 

The study even showed that living within a mile of a friend who is a happy person has a 25 percent chance of making you happier. The research identified clear clusters of happy and unhappy people within social networks, stating that the spread of happiness extends up to "three degrees of separation", meaning, if your friends are happy people, they can affect the happiness of their friends and their friends' friends.

Amazing. Amazingly simple.

You choose who you surround yourself with.

Disclaimer: I'm not asking you to abandon family. We all have a few familial killjoys that can bring you down if you let them. But let's come back to that in a moment.

The truth is you can be intentional about surrounding yourself with people who lift you up rather than drag you down. Entrepreneur, author and speaker, Jim Rohn, had it exactly right when he said "You are the average of the five people you spend the most time with." You're careful about who your children spend their time with and the influence those people have, why wouldn't you scrutinize the same for yourself?

The key is to stop and think about the people you spend the most time with. Ask yourself four key questions when considering these people:

  1. Do they continually unload their problems on you?
  2. Are they glass half-empty people?
  3. Do they find ways to be miserable?  
  4. Do they sap your energy/are they a lot of work?

If you're staring at a bunch of yes's, here's what's next -- and it's a bit brutal, but life's too short. Dramatically cut time with those who don't contribute to your happiness (or cut it out altogether), like you're cutting coupons. What you'll save isn't money, but energy, time to spend with others, and maybe just a little bit of your soul.

Now, how about dealing with those negative ions in your life that you can't just ditch? You can indeed have an upbeat impact on them, one that has a virtuous cycle effect as the new positivity reflects back on you.

The key with negative Nellie personalities is to first help them be aware of the impact their behavior is having on you; they likely don't appreciate the full impact of their gloominess.

Next, wear down their pessimism with your optimism. They just might get the message that their catastrophizing everything isn't welcome.

Finally, challenge their cynicism. Cynics get their power when they go unchecked. You can challenge their cynical statements and invite them to offer solutions or something positive minded instead. If they can't, they lose their power, and become more open to positivity.

Happiness doesn't have to be complicated. Start by controlling what you can -- like who you surround yourself with.