Separating cognitive development from language development in the acquisition of negation using international adoption.

Abstract

Children learning words face at least one challenge, maybe two. First, children must gather enough information to identify which concept maps to which word (a linguistic bottleneck). Second, for this mapping to be possible, children may need to acquire the concept itself if it is not already available (a conceptual bottleneck). We investigate whether children face both challenges or only the first when learning the English words for negation, a concept that is abstract and non-referential, yet universal across human thought and languages. We tested whether a linguistic bottleneck is sufficient to explain how children learn to express negation by comparing negation production in typical English-learners and older internationally-adopted preschoolers, who are more conceptually mature but face a similar language-learning task. If infants normally face a conceptual bottleneck, older adoptees, who do not, should learn negation faster. If the only bottleneck is linguistic, the two groups should learn negation at the same rate relative to their acquisition of English. In Study 1, parent reports on the CDI showed that older international adoptees and language-matched infant first-language learners begin producing no and not at the same point in vocabulary growth. Study 2 examined children’s production of logical denial uses of negation words in longitudinal corpora of parent-child interactions. Adopted preschoolers’ and language-matched infants’ production of denials increased at the same rate relative to the mean length of children’s utterances. Matching patterns of negation acquisition in internationally-adopted preschoolers and first-language-learning infants support a solely linguistic, not conceptual, bottleneck on learning negation words.