Switching Between Noun and Verb Agreement Rules Comes at a Cost: Cross-Sectional and Interventional Studies in a Developmental Sample

This study clarifies the impact of switching context between noun and verb number agreement rules in written language production. In Experiment 1, children from grade 3 to 6 were asked to fill in sentences with nouns and verbs in either a switching condition (noun followed by verb) or a repeating condition (noun followed by noun). The results showed that third- and fourth-grade children produced more erroneous agreements in the switching condition than in the repeating condition, showing that switching between rules comes at a cost, whereas fifth- and sixth-grade participants’ performance was not affected by the switching context. Based on these findings, Experiment 2 aimed to assess whether a switching treatment offers a greater opportunity to improve the acquisition of grammatical agreement production, as compared to a simple treatment. Teachers from grade 3 gave either a switching treatment (mixed noun and verb exercises) or a simple treatment (noun exercises followed by verb exercises). The results show that children learned better from the switching treatment than from the simple treatment. These findings highlight the cost of switching between noun and verb agreement rules during the acquisition of grammatical number agreement and also how grammatical spelling acquisition can be improved at school.