If you get involved with a slacker, prepare to see your own productivity drop off. If you're dating a dessert-lover, watch your waistline. In a new paper published in the Journal of Consumer Research, Cait Poynor Lamberton, a professor of Business Administration at the University of Pittsburgh, and Hristina Dzhogleva, a doctoral candidate, studied the effect of each partner’s self-control on joint decision-making. Lamberton and Dzhogleva recruited 74 people and classified them as having either “low” or “high” self-control based on their responses to statements like, “I have a hard time breaking bad habits” and “I get distracted easily.” They then arranged the participants into pairs and asked them to make a joint decision: either choosing items from a lunch menu or deciding at what point to give up on a challenging anagram. (The anagram was actually unsolvable.) Unsurprisingly, if both members of the pair had high self-control, they selected healthier foods and persisted longer on the puzzle, but if one member of the pair had low self-control, the two fared almost as poorly as when both members had low self-control. Or, as Dzhogleva and Lamberton say, the high self-control partner “assents to the lower self-control partner’s more indulgent preferences.