“…The latter is limited by memory limitations, attention span, lack of concentration, and other processing constraints, whereas the former is construed to be essentially infinite in virtue of the recursive nature of grammar. There are a number of methodological and theoretical issues with the competence/performance distinction (e.g., Reich, 1969 ; Pylyshyn, 1973 ; Christiansen, 1992 ; Petersson, 2005 ; see also Christiansen and Chater, Forthcoming 2016 ). Here, however, we focus on a substantial challenge to the standard solution, deriving from the considerable variation across languages and individuals in the use of recursive structures—differences that cannot readily be ascribed to performance factors.…”