Noncausal joint-action scenes facilitate Mandarin-speaking preschoolers’ interpretation of intransitive verbs with conjoined subjects

Children learn novel verb meanings by integrating sentence-level cues with information from the surrounding event. Although sentence frames provide information about verb transitivity, success with intransitive frames varies across languages and tasks. In Mandarin, preschoolers have been reported to struggle with conjoined-subject intransitive sentences, raising the question of whether this difficulty reflects a limitation in syntactic bootstrapping or partly stems from how children construe the comparison scenes. In a forced-choice pointing task, Mandarin-speaking 3-, 4-, and 5-year-olds heard transitive or conjoined-subject intransitive sentences containing novel verbs and chose between a causal scene and a noncausal scene. Critically, the noncausal scene was either a parallel-action scene or a joint-action scene. In the joint-action scene, the two participants acted together in physical contact but without a causal asymmetry. Children at all ages reliably matched transitive sentences to causal scenes. For intransitives, 3-year-olds performed at chance in both scene conditions, 4-year-olds succeeded only with joint-action scenes, and 5-year-olds succeeded in both. Thus, performance with intransitives improved with age and was facilitated when the noncausal alternative was easier to construe as a single noncausal event. These findings suggest that previously reported failures with Mandarin conjoined-subject intransitives cannot be attributed solely to insensitivity to argument structure, but also depend on how candidate events are visually and conceptually represented. More broadly, the results are consistent with a multiple-factor view of verb learning, in which syntactic cues interact with semantic, and event-based information.