Citation: Wood, A., Martin, J., & Niedenthal, P. (under review). Towards a Social Functional Account of Laughter: Acoustic Features Convey Reward, Affiliation, and Dominance For data files, supplementary results, and R code, [click here][1] To listen to or download the laugh samples, [click here][2] ABSTRACT: Recent work has identified the physical features of smiles that accomplish three tasks fundamental to human social living: rewarding behavior, establishing and managing affiliative bonds, and negotiating social status. The current work extends the social functional account to laughter. Participants (N = 762) rated the degree to which spontaneity, reward, affiliation, or dominance (between-subjects) was conveyed by 400 laughter samples acquired from a commercial sound effects website. We used 11 acoustic properties extracted from the laugh samples to predict participants’ ratings. Similar acoustic properties guided perceiver judgments of spontaneity and reward. Several acoustic properties predict affiliation differently than spontaneity and reward, confirming the benefit of separating the social functions of reward and affiliation. Dominance displayed the most distinct pattern of acoustic predictors. Actor sex moderated, and sometimes even reversed, the relation between acoustics and participants’ judgments. We relate the current findings to extant work on human and animal vocalizations and laughter. Considering laughter and smiles as tools that solve similar problems inherent to social living provides the groundwork for a better understanding of the origins and functions of both. [1]: https://osf.io/7s8ek/ [2]: https://osf.io/29gs7/