Examining children's verb learning in the United States and Japan: Do comparisons help?

Learning verbs is an important part of learning one's native language. Prior studies have shown that children younger than 5 years can have difficulty in learning and extending new verbs. The current study extended these studies by showing children multiple events that can be compared during learning, including Japanese- and English-speaking children. In the study, 2-, 3-, and 4-year-olds saw two similar events and then one varied (progressive alignment) or three varied (low alignable) events in a learning phase before test, and this was repeated for four sets. Children were asked to extend these novel verbs in easy (non-cross-mapping) and difficult (cross-mapping) test trials. A repeated-measures analysis of variance showed a significant Age by Condition interaction. In contrast to prior results, the 4-year-olds in both languages did well in both conditions and across test trial types. The 3-year-olds, especially in Japanese, performed best in the progressive alignment condition, showing that experience in seeing similar events was useful for verb learning. The 2-year-olds mostly struggled in this task, showing success only in the low-alignment condition, non-cross-mapping (easy) test trial. These are new findings given that no previous study has examined the role of different levels of variability during learning in a cross-language sample, and no prior study has examined the impact of objects at test in this way. This study shows that an important mechanism for verb learning-the comparison of events-could be useful across languages.