Speaking of causality: On the role of prosody in communicating subjective and objective causality in discourse

Language users distinguish between different types of causal relations, such as those that can be directly observed from the physical world (referred to as objective causality, e.g., “My daughter had a fight with her best friend, so she cried”), and those that are constructed by people in the mental world (referred to as subjective causality, e.g., “My daughter cried, so maybe she had a fight with her best friend”). Previous research has shown that coherence markers, such as specialized causal connectives (e.g., want ‘because’ and omdat ‘because’ in Dutch), can help people determine the type of causality the speaker intends to express. This dissertation focuses on the role of prosody—variation in pitch, loudness, or timing—in communicating these two different types of causality. The dissertation first investigates the use of prosody in expressing subjective and objective causality using a dialogue task. The results show that there is a trade-off between the use of prosody and the use of specialized causal connectives in expressing those two types of causality. This dissertation then examines the effect of prosodic information on the construction of subjective and objective causality. The results obtained from a discourse completion task indicate that the prosodic features of the English connective so affect listeners’ expectations of causal relations in upcoming discourse. These results provide new insights into how different types of causality are communicated in spoken discourse by showing that not only the lexical information (connectives), but also the prosodic information plays a crucial role.