Evaluating the accuracy of size perception on screen-based displays: Displayed objects appear smaller than real objects.

Accurate perception of the size of objects in computer-generated imagery is important for a growing number of applications that rely on absolute scale, such as medical visualization and architecture. Addressing this problem requires both the development of effective evaluation methods and an understanding of what visual information might contribute to differences between virtual displays and the real world. In the current study, we use 2 affordance judgments--perceived graspability of an object or reaching through an aperture--to compare size perception in high-fidelity graphical models presented on a large screen display to the real world. Our goals were to establish the use of perceived affordances within spaces near to the observer for evaluating computer graphics and to assess whether the graphical displays were perceived similarly to the real world. We varied the nature of the affordance task and whether or not the display enabled stereo presentation. We found that judgments of grasping and reaching through can be made effectively with screen-based displays. The affordance judgments revealed that sizes were perceived as smaller than in the real world. However, this difference was reduced when stereo viewing was enabled or when the virtual display was viewed before the real world.

Utilizing topology to generate and test theories of change.

Statistical and methodological innovations in the study of change are advancing rapidly, and visual tools have become an important component in model building and testing. Graphical representations such as path diagrams are necessary, but may be insufficient in the case of complex theories and models. Topology is a visual tool that connects theory and testable equations believed to capture the theorized patterns of change. Although some prior work has made use of topologies, these representations have often been generated as a result of the tested models. This article argues that utilizing topology a priori, when developing a theory, and applying analogous statistical models is a prudent method to conduct research. This article reviews topology by demonstrating how to build a topological representation of a theory and recover the implied equations, ultimately facilitating the transition from complex theory to testable model. Finally, topologies can guide researchers as they adjust or expand their theories in light of recent model testing.

Follow your heart: Emotion adaptively influences perception.

The current review introduces a new program of research that suggests the perception of spatial layout is influenced by emotions. Though perceptual systems are often described as closed and insulated, this review presents research suggesting that a variety of induced emotions (e.g., fear, disgust, sadness) can produce changes in vision and audition. Thus, the perceptual system may be highly interconnected, allowing emotional information to influence perceptions that, in turn, influence cognition. The body of work presented here also suggests that emotion-based changes in perception help us solve particular adaptive problems because emotion does not change all perceptions of the world. Taking the adaptive significance of emotion into account allows us to make predictions about when and how emotion influences perception.

Look before you leap: jumping ability affects distance perception.

Previous research has demonstrated that changing perceivers' action capabilities can affect their perception of the extent over which an action is performed. In the current study, we manipulated jumping ability by having participants wear ankle weights and examined the influence of this manipulation on the perception of jumpable and un-jumpable extents. When wearing ankle weights, jumpable gaps appeared longer than when not wearing ankle weights; however, for un-jumpable gaps, there was no difference in the apparent gap extent, regardless of whether the participant was wearing ankle weights. This suggests that the perception of a jumpable extent is affected by one's action boundary for jumping, but only if jumping is an action that can be performed over the extent.