Give a baby as young as a few months old the option to play with a nice puppet or a mean one and odds are she'll choose the nice one. But if the mean one has something to offer that the nice one doesn't—say, lots of baby wafers—most babies will put up with the mean puppet to get the larger reward, report researchers at Yale University. They go on to conclude in the journal Cognition that yes, even infants have a price, but they also stress a silver lining: "It was only when the difference between the offerings was very large that their aversion to the wrongdoer was overcome by personal incentives."
To conduct the study, researchers observed 64 12- and 13-month-olds as they watched a nice puppet help another puppet get a toy out of a box and a mean one slam that toy box lid shut. The puppets then offered the babies crackers, but the nice puppet had only one while the mean puppet had two, four, or eight (the number changed at random). Turns out that babies continued to show a preference for the nice puppet even though it had less to offer—until the offering reached eight crackers, the so-called tipping point. "When the mean puppet offers eight crackers and the nice puppet offers one cracker, two-thirds of babies will sell out or 'deal with the devil,' as we like to call this study," one researcher tells WSHU. Older kids held out longer, choosing to avoid the mean puppet all the way until it offered a whopping 16 crackers to the nice puppet's one. (Also, babies would really prefer that we sing.)