This paper reports findings from a between-subjects experiment that investigates how different learning content representations in virtual environments (VE) affect the process and outcomes of learning. Seventy-eight participants were subjected to an immersive virtual reality (VR) application, where they received identical instructional information, rendered in three different formats: as text in an overlay interface, as text embedded semantically in a virtual book, or as audio. Learning outcome measures, self-reports, and an electroencephalogram (EEG) were used to compare conditions. Results show that reading was superior to listening for the learning outcomes of retention, self-efficacy, and extraneous attention. Reading text from a virtual book was reported to be less cognitively demanding, compared to reading from an overlay interface. EEG analyses show significantly lower theta and higher alpha activation in the audio condition. The findings provide important considerations for the design of educational VR environments.