5 Things You Didn’t Know About Friendship, Backed By Research

Some insights about friendship from research, with links to the studies:

• The secret to making friendships last is staying in touch every two weeks.

• Yawning can tell you who your real friends are.

• Yes, the enemy of your enemy is your friend.

• There is a limit to how many real friends you can have — in life and on Facebook.

• More time with friends produces the happiness equivalent of an extra $133,000 a year.

For more on the science behind making new friends and strengthening the friendships you have, click here.