Achievement

Human beings seem to be able to judge whether an object is sitting so close to the end of a surface that it is likely to tip over. Trainee Steve Cholewiak and faculty Manish Singh have been studying the perception of object stability. Psychophysical experiments using a variety of 3D virtual object shapes showed that observers can precisely judge the tipping point of tilted objects depicted on surfaces and that perceived tipping points depend on the location of the object’s center-of-mass. Using a novel adaptation procedure, Cholewiak showed that judgments of tipping point were systematically biased following prolonged view of highly stable or unstable shapes. The results of the adaptation experiments show that stability perception results from operation of a dedicated perceptual module, rather than a high-level cognitive judgment. Rapid judgments of stability, like judgments of motion or depth, are crucial for providing appropriate signals to guide movement planning.