Humans rarely confuse variations in light intensity, such as shadows, shading, light sources and specular reflections, from variations in material properties, such as albedo or pigment. This review explores the cues, or regularities in the visual world that evidence suggests vision exploits to discriminate light from material. These cues include luminance relations, figural relations, 3D-shape,...

THE TOPIC of mortality risk perceptions has somehow failed to engage the interest of demographers. Perhaps this is because in demography, as in social science more generally, the passage from socioeconomic change to individual perceptions of change has been assumed to be immediate, or to involve lags of little consequence. If individual perceptions adjust quickly to changing empirical realities...

Robots interacting and collaborating with people need to comprehend and predict their movements. We present an approach to perceiving and modeling behaviors using a 3D virtual world. The robot's visual data is registered with the virtual world to construct a model of the dynamics of the behavior and to predict future motions using a physics engine. This enables the robot to visualize alternativ...