LexOPS: An R Package and User Interface for the Controlled Generation of Word Stimuli

Abstract

LexOPS is an R package and user interface designed to facilitate the generation of word stimuli for use in research. Notably, the tool permits the generation of suitably controlled word lists for any user-specified factorial design and can be adapted for use with any language. It features an intuitive graphical user interface, including the visualization of both the distributions within and relationships among variables of interest. An inbuilt database of English words is also provided, including a range of lexical variables commonly used in psycholinguistic research. This article introduces LexOPS, outlining the features of the package and detailing the sources of the inbuilt dataset. We also report a validation analysis, showing that, in comparison to stimuli of existing studies, stimuli optimized with LexOPS generally demonstrate greater constraint and consistency in variable manipulation and control. Current instructions for installing and using LexOPS are available at https://JackEdTaylor.github.io/LexOPSdocs/. This article presents LexOPS, a flexible R package which offers a comprehensive range of capabilities relevant to the generation of psycholinguistically controlled word stimuli. The appellation, 'LexOPS', is derived from four types of word properties commonly recognized in psycholinguistics-Lexical, Orthographic, Phonological, and Semantic. The most noteworthy feature of LexOPS is that itcan produce suitably controlled word stimuli for any possible user-specified factorial design. To support this functionality, the package features an easy-to-use graphical user interface in the form of a Shiny app (Chang, Cheng, Allaire, Xie, & McPherson, 2018), which provides multiple interactive visualizations and summaries of available word properties, as well as how stimuli LexOPS has generated relate to these properties. Another novel feature of the package is that it can work with any database of word variables which the user provides. This means that the user is not limited to built-in variables or words, but can design stimuli according to any numerically or categorically defined properties, for words from any language. Nevertheless, several useful psycholinguistic variables are included from a range of datasets to illustrate the capabilities of LexOPS. These also serve as a template demonstrating the expected format of the data if users wish to run LexOPS on their own databases. Open Practices StatementThe source code for the R package and inbuilt dataset are freely available at https://github.com/JackEdTaylor/LexOPS.