This chapter provides a critical discussion of the effects of experimental and environmental conditions on the incidental acquisition of vocabulary while reading. It begins with an explanation of ecological validity and delineates the importance of ensuring the ecological validity of research methods and procedures. The chapter then focuses on time on task and time on targets, before discussing the limitations and strengths of reading tasks under controlled conditions (e.g., in-class reading) or more natural conditions (e.g., out-of-class reading). Next, the effects of providing research participants with digital texts instead of print texts are considered, emphasizing the affordances of digital texts and e-glosses. The chapter concludes by commenting on reading environment issues. Researchers are encouraged to conduct more ecologically valid qualitative studies that examine the reading that takes place in digital environments, as well as more ecologically valid quantitative studies, in particular those that harness the power of eye-tracking to uncover connections between incidental vocabulary acquisition and language processing.