The person next to you yawns, and all of a sudden you can’t help but open your mouth, close your eyes, and take a gaping breath of air. It’s involuntary and seemingly contagious.

Well yawning isn’t the only thing that’s contagious, apparently so is drinking. If you partied hard on Friday night, it is more likely that your close friends did too.

Nicholas A. Christakis, Harvard Medical School professor and Pforzheimer House Master, recently released these findings in a new study. Along with obesity, loneliness, death, happiness, and smoking, drinking is now being labeled as a pastime that can affect those around you.

By using a social network of over 12,000 people during a span of 32 years, Christakis was able to analyze the impact of this network on the clustering of drinkers and non-drinkers and the subsequent consumption of alcohol. He also examined the nature of social ties, noting that close friends and family had a larger impact on drinking than neighbors or colleagues.

Up until three degrees of separation, Christakis concluded that social networks can strongly impact the way in which we act and the life decisions that we make concerning alcohol consumption.

Next time you and your roommate wake up with raging hangovers, you’ll know that whoever took the first sip made the other 50% more likely to drink. Make sure to guilt that friend into bringing you breakfast in bed and some Advil. After all, drinking (like yawning) is contagious and therefore your current hangover was partly their fault. Right?

Photo courtesy of Nejmlez/Wikimedia Commons.