Think of the Consequences: A Decade of Discourse about Same-Sex Marriage

Approaching issues through the lens of non-negotiable values increases the perceived intractability of debate (Baron & Spranca, 1997), while focusing on concrete consequences of policies instead results in the moderation of extreme opinions (Fernbach et al., 2013) and greater likelihood of conflict resolution (Baron & Leshner, 2000). Using comments on the popular social media platform Reddit from January 2006 until September 2017, we show how changes in the framing of same-sex marriage in public discourse relate to changes in public opinion. We use a topic model to show that the contribution of certain protected-values-based topics to the debate (religious arguments and freedom of opinion) increased prior to the emergence of a public consensus in support of same-sex marriage (Gallup, 2017), and declined afterwards. In contrast, discussion of certain consequentialist topics (the impact of politicians’ stance and same-sex marriage as a matter of policy) showed the opposite pattern. Our results reinforce the meaningfulness of protected values and consequentialism as relevant dimensions for describing public discourse and highlight the usefulness of unsupervised machine learning methods in tackling questions about social attitude change.