Virtual and mixed reality environments (VMRE) often imply full-body human-computer interaction scenarios. We used a public multimodal mixed reality installation, the Synthetic Oracle, and a between-groups design to study the effects of implicit (e.g., passively walking) or explicit (e.g., pointing) interaction modes on the users' emotional and engagement experiences, and we assessed it using questionnaires. Additionally, real-time arm motion data was used to categorize the user behavior and to provide interaction possibilities for the explicit interaction group. The results show that the online behavior classification corresponded well to the users' interaction mode. In addition, contrary to the explicit interaction, the engagement ratings from implicit users were positively correlated with a valence but were uncorrelated with arousal ratings. Interestingly, arousal levels were correlated with different behaviors displayed by the visitors depending on the interaction mode. Hence, this study confirms that the activity level and behavior of users modulates their experience, and that in turn, the interaction mode modulates their behavior. Thus, these results show the importance of the selected interaction mode when designing users' experiences in VMRE.

Future mixed reality systems will need to support large numbers of simultaneous, nonexpert users at reasonable per-user costs if the systems are to be widely deployed within society in the short to medium term. We have constructed a prototype of such a system, an interactive entertainment space called Ada that was designed to behave like a simple organism. Using Ada we conducted two studies: the first assessing the effect of varying the operating parameters of the space on the collective behavior and attitudes of its users, and the second assessing the relationships among user demographics, behavior, and attitudes. Our results showed that small changes in the ambient settings of the environment have a significant effect on both user attitudes and behavior, and that the changes in user attitudes do not necessarily correspond to the environmental changes. We also found that individual user opinions are affected by demographics and reflected in overt behavior. Using these results, we propose some tentative guidelines for the design of future shared mixed reality spaces.