Despite the wide range of theoretical explanations for human laughter, it is generally agreed to function, at least in part, as a social signal. We tested the hypothesis that laughter serves as a signal of group affiliation. Participants viewed a video clip depicting a confederate partner of unknown group affiliation displaying either a neutral expression, a smile, or laughter in response to a joke told at the expense of a member of the in-group or the out-group. Participants then decided whether to help the confederate in a fictional and incentivized economic game. When viewed in response to a joke told at the expense of the in-group member, participants were less likely to help after viewing the laughter clip in comparison to the neutral and smiling clips. However, when viewed in response to a joke told at the expense of the out-group member, participants were more likely to help after viewing the smiling clip in comparison to the neutral and laughter clips. Taken together, these findings suggest that laughter may serve to signal affiliation, albeit only among out-group members.

尽管对人类笑声的理论解释范围很广，但人们普遍认为它至少在一定程度上是一种社会信号。我们检验了笑声是群体归属信号的假设。参与者观看了一段视频片段，该视频片段描绘了一个未知群体隶属关系的同盟伙伴，在回应一个以牺牲群体内或群体外成员为代价的笑话时，会表现出中性的表情、微笑或大笑。然后，参与者决定是否在虚构的、激励性的经济游戏中帮助邦联。当观看以牺牲小组内成员为代价的笑话时，与中性和微笑剪辑相比，参与者在观看笑声剪辑后不太可能提供帮助。然而，当看到一个以牺牲组外成员为代价的笑话时，与中性和笑声剪辑相比，参与者在观看微笑剪辑后更有可能提供帮助。综上所述，这些发现表明，笑声可能有助于表明从属关系，尽管仅限于外群体成员。