The surprising science behind wonderful friendships

Julianne Holt-Lunstad did a meta-analysis of social support and health outcomes and found that not having enough friends or having a weak social circle is the same risk factor as smoking 15 cigarettes a day.

We've had such great public health campaigns against smoking in the last 20-odd years, and now we're finally learning that having a good and satisfying social life is just as important, if not more important, than avoiding cigarettes.

They understand your behavior patterns, they've seen you over time in different situations, and they know the blind spots you have.

One researcher found that friends rate our IQ more accurately than we do ourselves. And what's funny is we tend to give ourselves a lower IQ than our friends do — but our friends are more accurate.

If you are really willing to listen to a friend when she's giving you a little bit of tough love, you can learn a great deal about yourself. This is a powerful benefit good friendships offer us.

I think the biggest mistake we commonly make is that we're not conscious about friendships. With romantic relationships, people spend a lot of time thinking "What kind of person would be good for me? What kind of person do I want to date"?

But with friendships, we don't give it much thought.Sometimes that's beautiful and it works out well. But a lot of times we just drift into them and, over time, adopt the values and habits of a group that may or may not be in our best interest.

"Peer pressure" has this negative connotation because we usually just apply it to teens pressuring each other to do bad things. For teens and adults it can have both positive and negative effects.

Research shows over time, you develop the eating habits, health habits and even career aspirations of those around you. If you're in a group of people who have really high goals for themselves you'll take on that same sense of seriousness.

And conversely, if you're in a group of friends who are not that ambitious, then you too will lower your standards.

Being more conscious about how much our friends affect us is important, especially when we're first meeting people. You have to ask yourself "Who do I admire? Who do I want to be like in five years? Those are the people I should be trying to get close to and trying to develop authentic friendships with." [Friendfluence: The Surprising Ways Friends Make Us Who We Are]

Reach out to your good friends and tell them how much they mean to you. It's just not something we're accustomed to doing. It'll make you feel great, it'll make them feel great and it will strengthen the bond between you.

Be more giving to the friends you already have. People in romantic relationships always celebrate anniversaries, yet you might have a friend for 15 years and you've probably never gone out to dinner and raised a glass to that. We need to cherish our friendships more. [Friendfluence: The Surprising Ways Friends Make Us Who We Are]