The effect of contextual diversity on L1 and L2 word learning: A systematic review and meta-analysis

Abstract

In prior studies, contextual diversity (CD) has been shown to significantly impact word learning, yet gaps remain in understanding its theoretical underpinnings and moderating factors. This research aimed to synthesize trends in CD studies, evaluate the heterogeneity in its definitions and operationalizations, explore its correlation with word learning, and examine potential moderators influencing this relationship. After a literature search and application of screening criteria, we conducted a systematic review and meta-analysis of 20 empirical studies. The primary target population comprises both L1 monolingual and L2 bilingual speakers. Behavioral studies revealed a significant effect of CD on word learning (Cohen’s d = 0.44, p < .001). Eye-tracking data demonstrated significant effects during early and later stages of processing, reflecting heightened attention: first fixation duration: d = −0.365, p = .023, gaze duration: d = −0.574, p = .005, go-past time: d = −0.749, p = .023, and total time: d = −0.691, p = .009. Moderator analysis identified age as a key factor, while gaps in theoretical frameworks and assessments of cognitive moderators were noted. These findings highlight the need for integrating offline and online methods and developing clearer theoretical models to advance our understanding of CD.