Whoever is not with me is against me: The costs of neutrality among friends

•We find that people respond negatively to neutrality in some circumstances.•People's negative response to neutrality is moderated by relationship closeness between the two disputants and the side-taker.•These results suggest the importance of understanding multilateral interactions.

Although friends provide valuable help and support, they can also entangle us in costly conflicts. In three studies, we investigate how people react when they are in a dispute with another person and their friend opposes them, supports them, or remains neutral. As expected, participants felt negative toward a friend who sided against them and positive toward a friend who sided with them. However, we were most interested in how people react to a friend's neutrality. People might view neutrality as a fair and positive way to avoid escalating conflict, but they could also see it as shirking one's duties to support a friend. In line with a recent alliance model of friendship, we predicted and found support for the latter: participants reacted negatively toward a friend who remained neutral, in fact just as negatively as toward a friend who actively opposed them. That is, participants' felt similar to the Biblical aphorism, “whoever is not with me is against me.” We further found that participants' negative response to neutrality was particularly strong when a close friend remained neutral during a dispute with a distant friend, compared to a dispute with an equally close friend. We discuss the implications of these findings for understanding multilateral conflicts among multiple friends.