Mobile devices and apps have become a standard for the museum experience. Many studies have begun to explore the impact mobile apps may have on user experience and informal learning. However, there has been relatively little research on how visitor groups interact collaboratively while using these devices in computer-supported collaborative learning (CSCL) environments. In this paper, we explore the impact of a mobile question-asking app on museum visitor group interactions using the Interactive-Constructive-Active-Passive (ICAP) framework, a hierarchical taxonomy that differentiates modes of cognitive engagement. In a post-hoc analysis of survey findings from a study conducted at two large museums in the American southwest, we found that our app encouraged sharing of information among group members. In addition, users of a gamified version of the app were significantly more likely to report engaging in a group discussion during question-asking than groups using a non-game version of the app. We also found that group collaboration levels depended on the group-designated primary user of the app. Whenever a child or the group collaboratively asked the most questions, group discussion frequency was significantly higher. The study's findings support mobile question-asking apps' viability as a means to better understanding of museum visitor groups' interactions with exhibit content and provide evidence that game-based mobile apps, designed to foster question-asking by visitors, may bolster collaborative group interactions and informal learning.