Diversity in research on the psychology of language: A large-scale examination of sampling bias

The human capacity for language cannot be fully understood without appreciation of its ability to adapt to startling diversity. Narrow sampling therefore undermines the psycholinguistic enterprise. Concerns regarding a lack of sample diversity in psycholinguistics are increasingly being raised, but large-scale data on the state of the field remain absent. In the current paper, we address this empirical gap by documenting sample diversity in over 5500 psycholinguistic studies published over two decades. Moreover, we consider several hitherto unexplored issues regarding diversity in (psycho)linguistics, including the impact of sample biases on knowledge uptake and the implementation of diversification strategies often proposed in the literature. We identify marked overrepresentations in the data - of English, North America, and tertiary education students - and provide new evidence of their consequences, where papers on more commonly studied languages and locations tend to be cited more. We also demonstrate that absolute diversity has increased over time, albeit insufficiently to disrupt the linguistic and geographic concentrations observed. We find that representation of Global South researchers and contexts has grown, but this growth is centered in a handful of countries (China, Israel), and Africa and Southeast Asia remain severely underrepresented. Regarding the implementation of diversification strategies, we show that online data collection has yet to contribute much to diversification, while cross-national collaboration is effective in this respect. Finally, we challenge prevalent conceptions of diversification in which "exotic" languages spoken in remote locations assume a central role by highlighting the neglected linguistic diversity of the major hubs of psycholinguistic knowledge production.