 There has been much discussion on whether, and under what conditions, real-world preferences fall into such a restricted domain. It has been suggested, for example, that group deliberation can induce single-peaked preferences, by leading participants to focus on a shared cognitive or ideological dimension (a ‘meta-agreement’) (Miller 1992; Knight and Johnson 1994; Dryzek and List 2003). Experimental evidence from deliberative opinion polls, where participants’ preferences were elicited before and after a period of group deliberation, is consistent with this hypothesis (List, Luskin, Fishkin, and McLean 2013), though further empirical work is needed. For a critical assessment of the idea of deliberation-induced ‘meta-agreement’, see Ottonelli and Porello (2013). For a recent computational study, see Rafiee Rad and Roy (2021).