Children's acquisition of the transitivity status of novel verbs was examined to test whether preemption helps children learn to avoid non-conventional uses of verbs. Given that many English verbs alternate between transitive and intransitive usage (e.g. break, roll), how do children learn the fixed transitive status of verbs such as hit or the fixed intransitive status of verbs such as fall? 48 four-year-olds and 48 six- and seven-year-olds learned two novel verbs, with one verb modelled as transitive and the other as intransitive. Exposure conditions varied the occurrence and type of preemptive evidence potentially facilitating learning of the verbs' transitivity status. In comparison to a No Preemption group, only six- to seven-year-olds exposed to novel verbs in alternative constructions (that allowed them to talk about the actions from the perspective of the agent or patient without changing the verbs' assigned transitivity) produced fewer utterances violating the verbs' fixed transitivity. The results identify limits in children's usage of indirect negative evidence in acquiring verb argument structure constructions.