Relational categories have been the focus of much recent research (Asmuth &Gentner, 2017; Gentner, 2005; Gentner & Kurtz, 2005; Goldwater & Markman, 2011;Markman & Stilwell, 2001; Ross & Murphy, 1999), in part because of their importantrole in conceptual learning and education (Goldwater & Schalk, 2016).

Relational cate-gories are categories for which the basis for membership is participation in a commonrelational structure; thus, they differ from the more studied entity categories, such as tulipand spoon, whose members share many intrinsic properties.

Our main focus is on relational abstractions, includingprinciples, rules, and schemas, as well as abstract relational categories.