Here’s the scene:

You’re divvying up the weekend errands. You ask your husband to drop the kids at soccer and pick up some chicken for dinner. He ferries your kids but forgets the rest of the carpool and comes back with a bucket of fried chicken instead of the healthy skinless chicken breasts you wanted to make stir-fry with. Is he trying to drive you crazy? No, he’s trying to help, but take a moment and you’ll see that your instructions were really not as clear as you thought—and you two aren’t the only ones prone to this kind of mix-up. According to a study from the University of Chicago, the biggestcommunication problems can arise between the closest of companions.

Researchers paired up volunteers on two-person teams that played a communications game. The people in each couple were given different amounts of information, and when they had to convey a message, the partners who shared more knowledge with each other were more likely to rely on shortcuts and less likely to utilize detailed descriptions, which led to more ambiguity. Boaz Keysar, Ph.D., professor of psychology and study coauthor, says the experiment suggests that people who assume they have a common base of knowledge, as people who are close usually do, can actually communicate less effectively because of that assumption. Especially when we have new information to relay, those short, vague messages we use with people we know well can leave our meanings unclear. “In general, we do tend to communicate well with the people we are closest to, but as soon as we start talking about new things that aren’t part of our shared knowledge—like a new job or a hobby we’ve just started—we start to fail far more often than when we talk to strangers,” he says. We’re better off spelling things out when in doubt—and cutting our partners some communicative slack. —Katie Brophy