A megastudy of lexico-semantic effects in single-word shadowing

Lexico-semantic effects in lexical decision and semantic categorisation tasks have been investigated using the megastudy approach, but not with other traditional spoken word recognition tasks. To address this gap, this megastudy examined the single-word shadowing task, where 96 native English speakers repeated aloud each word they heard as quickly and as accurately as possible. Item-level hierarchical regression and linear mixed-effects analyses produced identical results: Words with longer token duration were associated with slower response times while high-frequency and phonologically distinctive words were repeated faster. These findings were consistent with previous studies and other tasks, which suggests that lexical effects are task-general in spoken word recognition. However, after controlling for lexical variables, six semantic variables did not account for any additional unique variance in response times. These results suggest that the single-word shadowing task is heavily dependent on lexical processing and can be completed without activating semantics. Cross-task comparisons with another megastudy's data on auditory lexical decision and semantic categorisation tasks further suggest that lexical effects are task-general, while semantic richness effects are task-specific in spoken word recognition.