The acquisition of causal connectives: the role of parental input and cognitive complexity

Abstract

One of the milestones in children’s language development is the ability to construct a discourse. In order to construct a discourse, children must learn to set up coherence relations between clauses. In this study, we focused on the acquisition of causal relations, and in particular on children’s development of causal connectives, such as because, that are used to mark causal relations. For example, children can use because to mark the objective cause-consequence relation in (1) or the subjective claim-argument relation in (2). (1) He’s so fat because there’s uh baby inside. (Shem, 3;00.05) (2) He’s a baby because he goes in a stroller. (Nina, 3;00.10) In this study we tracked young children’s production of causal connectives by running growth-curve analyses on longitudinal corpora. We investigated the role of two factors that have been hypothesized to influence the course of connective acquisition: parental input and cognitive complexity. We took a cross-linguistic approach by studying English because as well as its German counterpart weil and the Dutch equivalents want and omdat. In addition, we tested young children’s comprehension of causal relations in an innovative eye-tracking experiment that used the preferential looking paradigm. Results revealed that both cognitive complexity and parental input play a role during connective acquisition. We showed that the cognitive complexity of objective and subjective relations determines the acquisition order of these relations: the comprehension and production of the least complex objective causal relations develop ahead of that of the more complex subjective causal relations. We also showed that both parental connective input and parental scaffolding through why-questions influence the course of acquisition. In fact, our analysis of parental scaffolding through why-questions showed that effects of input and complexity are intertwined: parents adapt the complexity of these question-answer routines to their child’s cognitive ability. Our findings allowed us to construct a model of causal connective development. It consists of four phases that are cumulative in nature, each phase adding an extra ability to the previous one(s). First, children start out by developing an understanding of causality in which their comprehension of objective causality develops ahead of that of subjective causality. Second, parents start to scaffold connective production by asking why-questions. Children give a causal response to these questions, but do not use a connective to mark the relation. Third, children start to include connectives in their responses to why-questions, and they start to use connectives independently (on their accord). When we look at the type of relations they produce, we find that objective relations develop before subjective relations. Fourth, children start asking why-question themselves. While answering these questions, parents make use of causal connectives, and thereby provide input ‘on demand’. In this study we have used converging evidence – with different languages and different methods – to investigate causal connective acquisition. We have shown that connective acquisition is an intricate system in which parental input and cognitive complexity play an important role.