Detecting changes between real-world objects using spatiochromatic filters

A behavioral and computational treatment of change detection is reported. The behavioral task was to judge whether a single object substitution change occurred between two “flickering” 9-object scenes. Detection performance was found to vary with the similarity of the changing objects; object changes violating orientation and category yielded the fastest and most accurate detection responses. To account for these data, theBOLAR model was developed, which uses color, orientation, and scale selective filters to compute the visual dissimilarity between the pre- and postchange objects from the behavioral study. Relating the magnitude of the BOLAR difference signals to change detection performance revealed that object pairs estimated as visually least similar were the same object pairs most easily detected by observers. The BOLAR model advances change detection theory by (1) demonstrating that the visual similarity between the change patterns can account for much of the variability in change detection behavior, and (2) providing a computational technique for quantifying these visual similarity relationships for real-world objects.     

Where Do We Go from Here?

Beginning with the End represents an excellent collection of articles devoted to the thought of Wolfhart Pannenberg. This volume includes many of the most important thinkers in the science-religion dialogue and shows as well the importance and impact of Pannenberg's theology. This response addresses themes that surface in several of the articles: What is religion? What is science? What is theology? What is God? On some of these themes there is agreement, on others sharp disagreement. The conclusion also considers what this volume suggests about the future of Pannenberg's theology.     

Measuring Judgments of Professionals: Using Vignettes in a Social Survey About Patient Confusion

The use of a factorial survey to measure the clinical judgments of professionals is described. This design allows the researcher to partial out the effects of variables on clinical decision making while using probability sampling. Methods frequently used to study judgments are reviewed and a study of nurses' judgments about patients' confusional episodes are used to illustrate the application of the factorial survey. Acute confusion in patients is a common clinical problem for nurses working in medical-surgical units in acute care hospitals. Using the factorial survey to study a real-life problem such as confusion demonstrates how this design can be used to test judgments in complex clinical situations, to aid in concept development, and to identify consensus among professionals.     

Stories and Cases: Discernment and Inference in Moral Deliberation

Theoretical Medicine and Bioethics -     

Parsing silhouettes: The short-cut rule

Many researchers have proposed that, for the purpose of recognition, human vision parses shapes into component parts. Precisely how is not yet known. The minima rule for silhouettes (Hoffman & Richards, 1984) defines boundary points at which to parse but does not tell how to use these points to cut silhouettes and, therefore, does not tell what the parts are. In this paper, we propose the short-cut rule, which states that, other things being equal, human vision prefers to use the shortest possible cuts to parse silhouettes. We motivate this rule, and the well-known Petter’s rule for modal completion, by the principle of transversality. We present five psychophysical experiments that test the short-cut rule, show that it successfully predicts part cuts that connect boundary points given by the minima rule, and show that it can also create new boundary points.