Disjunctive Inference in Preverbal Infants

Abstract

Can preverbal infants already use logical reasoning such as disjunctive inference? This reasoning requires keeping two possibilities open (A or B), until one of them is eliminated (if not A), allowing the inference: B is true. We used a paradigm based on 10-month-olds’ social skills and their ability to pair face and voice: We first presented an ambiguous situation: a female voice and two faces, then one of the faces was presented with a male voice implying that the initial voice belonged to the other face. We measured infants’ preference for the correct face when both faces and the initial voice were again presented, as well as infants’ pupillary response, as an indicator of cognitive load at the critical moment of disjunctive inference. We controlled for other possible explanations in 3 additional experiments. Our results show that 10-month-olds can correctly deploy disjunction and negation to disambiguate scenes, suggesting that disjunctive inference does not rely on linguistic constructs.