A new study suggests that a good way to quit smoking is to be around others who have quit. Researchers from the University of California at San Diego found a 67 percent chance that a person will kick the habit if a spouse does; 36 percent chance if a friend does; a 25 percent chance if a sibling does and a 34 percent chance if a coworker does.

“It’s sort of like watching dominoes,” said study coauthor James Fowler. “If one falls, it very quickly causes others to fall. People are not quitting on their own; they’re quitting in droves.”

Read how Law and Order’s S. Epatha Merkerson learned to live a smoke-free life.