  The rise of Mixed Reality (MR) stimulates new interactive techniques that
seamlessly blend the virtual and physical environments. Just as virtual content
could be overlayed onto the physical world for providing adaptive user
interfaces [5, 8], emergent techniques "repurpose" everyday environments and
sensory cues to support the virtual content [7, 9, 13-15]. For instance, a
strong wind gust in the real world, rather than being distracting to the
virtual experience, can be mapped with trees swaying in MR to achieve a
unifying experience [15], as shown in Figure 1. Such techniques introduce
stronger immersion, but they also expose users to overlooked perceptual
manipulations, where safety risks arise from misperception of real-world
events. In this work, we apply a causal inference perspective to understand the
harms of repurposing real-world sensory cues for MR. We argue that by viewing
the MR experience as a causal inference process of interpreting cues arising
from both the virtual and physical world, MR designers and researchers can gain
a new lens to understand potential perceptual manipulation harms.
