Symmetric predicates and the semantics of reciprocal alternations

Reciprocal alternations appear with binary predicates that also have a collective unary form. Many of these binary predicates are symmetric : if A dated B then B dated A. Most symmetric predicates in English show a simple kind of reciprocity: A and B dated means “A dated B”, or equivalently “B dated A”. Similar observations hold for nouns and adjectives like cousin and identical . Non-symmetric predicates like hug , fight and kiss also show reciprocity, but of a more complex kind. For instance, the meaning of A and B hugged differs substantially from “A hugged B and/or B hugged A”. Addressing a wide range of reciprocal predicates, we observe that “plain” reciprocity only appears with symmetric predicates, while other types of reciprocity only appear with non-symmetric predicates. This Reciprocity-Symmetry Generalization motivates a lexical operator that derives symmetric predicates from collective meanings. By contrast, reciprocity with non-symmetric predicates is analyzed using “soft” preferences of predicate concepts. Developing work by Dowty and Rappaport-Hovav & Levin, we introduce a formal semantic notion of protopredicates , which mediates between lexical meanings and concepts. This mechanism explains symmetry and reciprocity as two semantic aspects of one type system at the lexical-conceptual interface. EARLY ACCESS