DerLex: An eye-movement database of derived word reading in English

This paper introduces a new database of eye-tracking data on English derived words, DerLex. A total of 598 unique derived suffixed words were embedded in sentences and read by 357 participants representing both university convenience pools and community pools of non-college-bound adults. Besides the eye-movement record of reading derived suffixed words, the DerLex database provides the author recognition test (ART) scores for each participant, tapping into their reading proficiency, as well as multiple lexical variables reflecting distributional, orthographic, phonological, and semantic features of the words, their constituent morphemes, and morphological families. The paper additionally reports the main effects of select lexical variables and their interactions with the ART scores. It also produces estimates of statistical power and sample sizes required to reliably detect those lexical effects. While some effects are robust and can be readily detected even in a small-scale typical experiment, the over-powered DerLex database does not offer sufficient power to detect many other effects—including those of theoretical importance for existing accounts of morphological processing. We believe that both the availability of the new data resource and the limitations it provides for the planning and design of upcoming experiments are useful for future research on morphological complexity.