The role of working memory in structural priming during language comprehension: Evidence from a visual-world paradigm

Many studies found that structural priming in production relied on cognitive resources (e.g., working memory), suggesting a resource-constrained mechanism of syntactic processing. To investigate the mechanism of structural priming in comprehension (automatic vs. resource-constrained), we constructed two eye-tracking experiments to test the role of working memory (i.e., a number series recall task between prime and target exerting high or low working memory load) in structural priming during visual-world comprehension. The priming effect is evaluated by the proportion of looks to predicted referents for two critical time windows in target sentence processing: the target verb and the first syllable of the first postverbal noun. When prime and target involved different verbs (Experiment 1), structural priming in both time windows was similar between the high- and low-load conditions. When prime and target involved same verbs (Experiment 2), structural priming in the time window of the first syllable of the first noun phrase was weaker in the high-load than in the low-load condition. Within the time window of the first syllable of the first noun phrase, a lexical boost effect occurred in the low-load condition but not in the high-low condition. Overall, structural priming in comprehension is partially automatic, while lexically mediated structural priming is modulated by working memory, supporting the implicit learning theory.