Shedding Light on Cast Shadows: An Investigation of Perceived Ground Contact in AR and VR.

Virtual objects in augmented reality (AR) often appear to float atop real world surfaces, which makes it difficult to determine where they are positioned in space. This is problematic as many applications for AR require accurate spatial perception. In the current study, we examine how the way we render cast shadows-which act as an important monocular depth cue for creating a sense of contact between an object and the surface beneath it-impacts spatial perception. Over two experiments, we evaluate people's sense of surface contact given both traditional and non-traditional shadow shading methods in optical see-through augmented reality (OST AR), video see-through augmented reality (VST AR), and virtual reality (VR) head-mounted displays. Our results provide evidence that nontraditional shading techniques for rendering shadows in AR displays may enhance the accuracy of one's perception of surface contact. This finding implies a possible tradeoff between photorealism and accuracy of depth perception, especially in OST AR displays. However, it also supports the use of more stylized graphics like non-traditional cast shadows to improve perception and interaction in AR applications.

Expertise effects on the perceptual and cognitive tasks of indoor rock climbing.

Experts' cognitive abilities adapt in response to the challenges they face in order to produce elite-level performance. Expert athletes, in particular, must integrate their motor capabilities with their cognitive and perceptual processes. Indoor rock climbers are particularly unique athletes in that much of the challenge they face is to accurately perceive and consolidate multiple movements into manageable action plans. In the current study, we investigated how climbers' level of expertise influenced their perception of action capabilities, visual memory of holds, and memory of planned and performed motor sequences. In Experiment 1, climbers judged their perceived capability to perform single climbing moves and then attempted each movement. Skilled climbers were less confident, but perceived their action capabilities more accurately than less skilled climbers. In Experiment 2, climbers recalled holds on a route, as well as predicted and recalled move sequences before and after climbing, respectively. Expertise was positively associated with visual memory performance as well as planned and recalled motor sequence accuracy. Together, these findings contribute to our knowledge of motor expertise and suggest that motor expert's ability to accurately estimate their action capabilities may underlie complex cognitive processes in their domain of expertise.

Mind the Gap: Gap Affordance Judgments of Children, Teens, and Adults in an Immersive Virtual Environment.

Affordances are possibilities for action that depend on both an observer's capabilities and the properties of the environment. Immersive Virtual Environments (IVEs) have been used to examine affordances in adults, demonstrating that judgments about action capabilities are made similarly to the real world. However, less is known about affordance judgments in middle-aged children and adolescents in IVEs. Differences in rate of growth, decision criteria, and perceived risk could influence affordance judgments for children. In Experiment 1, children, teens, and adults stood in an IVE at ground level or at a height of 15 m, and were asked to view gaps of different widths. Across all age groups, estimates of gap crossing were underestimated at the higher height compared to the ground, consistent with reports of fear and risk of falling. Children, compared to adults, underestimated their maximum crossable gap compared to their actual crossable gap. To test whether this difference was specific to IVEs or a more generalized age effect, children and adults were tested on gap estimates in the real world in Experiment 2. This real world study showed no difference between children and adults, suggesting a unique contribution of the IVE to children's affordance judgments. We discuss the implications for using IVEs to study children's affordances.