Abstract
The purpose of the thesis is to investigate 5-year-old Mandarin-speaking children’s interpretation of modals. Using the Hidden Box Task, Experiment 1 was designed to test 5-year-old Mandarin-speaking children’s understanding of the epistemic modals yiding ‘must’ and keneng ‘might’. The results revealed that children’s performance was adult-like in the determined condition but not in the undetermined condition. Children’s difficulty in contexts of uncertainty was reflected by both positive bias and the tendency of Premature Closure. Compared with the results from Moscati and Crain (2014) and Moscati, Zhan & Zhou (2016), we suggested that the lexical size of modal expressions had impacts on learning epistemic modals. Experiment 2 investigated children’s ability to derive scalar implicature. The results revealed that 5-year-old children did not generate scalar implicature in the Hidden Box Task. They consistently accepted the weak expression keneng ‘might’ when the scenario was compatible with the strong modal yiding ‘must’. Experiment 3 examined children’s understanding of negative sentences with the epistemic modals yinggai ‘should’ and yiding ‘must’. The findings supported the Semantic Subset Principle that children acquire the strong expressions earlier than the weak expressions, regardless of the word order. By unifying the results of the three experiments, we suggested that the difficulty in undetermined condition and interpreting the weak expression may come from the same source: the cognitive difficulty in coping with multiple possibilities. That is, the cognitive difficulty in coping with multiple possibilities hinders 5-year-old Mandarin-speaking children from demonstrating their modal competence.