Inferences are crucial to successful discourse comprehension. We
assessed the contributions of vocabulary and working memory to
inference making in children aged 5 and 6 years (n = 44), 7 and
8 years (n = 43), and 9 and 10 years (n = 43). Children listened to
short narratives and answered questions to assess local and global
coherence inferences after each one. Analysis of variance (ANOVA)
confirmed developmental improvements on both types of inference.
Although standardized measures of both vocabulary and
working memory were correlated with inference making, multiple
regression analyses determined that vocabulary was the key predictor.
For local coherence inferences, only vocabulary predicted
unique variance for the 6- and 8-year-olds; in contrast, none of
the variables predicted performance for the 10-year-olds. For global
coherence inferences, vocabulary was the only unique predictor
for each age group. Mediation analysis confirmed that
although working memory was associated with the ability to generate
local and global coherence inferences in 6- to 10-year-olds,
the effect was mediated by vocabulary. We conclude that vocabulary
knowledge supports inference making in two ways: through
knowledge of word meanings required to generate inferences
and through its contribution to memory processes.