Background: Immersive virtual reality (IVR) is a new technology that could motivate learners, but also could contain distracting elements that increase cognitive demands on learners. In contrast, learning with conventional media, such as a narrated slideshow could be less motivating, but also less distracting. Objectives: This experiment investigates: (1) in what situations executive function and working memory capacity play a role in learning in IVR and a slideshow lesson and (2) whether people learn science content better with IVR or with a narrated slideshow lesson. Method: Participants watched a lesson on ocean acidification either using a head-mounted display IVR device or a pre-recorded narrated slideshow lesson. A week later, they took a test on this material and completed tasks to assess executive function and working memory capacity. Results and Conclusion: On a post-test, there was no difference between IVR and slideshow lessons, but there were differences in the role of executive function in learning with these two media. For students learning in IVR, executive function correlated significantly with post-test scores, such that learners with stronger executive function did better on the posttest than those with weaker executive function, while for students learning with a slideshow lesson, executive function and working memory capacity did not correlate significantly with posttest scores. This research indicates that it is important to understand how a learner's attentional controls impact their understanding when using IVR for learning.