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Biomedical subjects

K Berbaum

Publications and source records attributed to K Berbaum.

25 records · Page 2Linked to original sources
PubMed1983

Objects in the path of apparent motion.

Experiments by several investigators suggest that forms between inducing stimuli for apparent motion may deflect motion from a straight path. In an experiment in which a binocularly viewed object was sometimes positioned between the inducing dots, we discovered that the degree of curvature of the path that is most likely to be reported depends upon the interstimulus interval whether or not the space between inducing dots contains an object. The interstimulus interval at which motion is most frequently reported is longer for curved paths of motion than for linear paths even though the spatial separation of inducing stimuli is held constant. The results suggest that apparent motion in depth is not based upon form.

Humans↗
PubMed1981

Dimensions of figural identity and apparent motion.

Warren proposed that for apparent motion to be perceived between disparate shapes, the shapes must be identifiable as the same object. When disparate shapes are seen as different views of the same rigid form, they are called ecologically transformable. Ecological transformability seemed to be the crucial variable in Warren's results. However, Warren's findings conflict with those of Kolers and Pomerantz, who obtained frequent reports of apparent motion of disparate, non-transformable shapes. This discrepancy may be due to the response categories used in Warren's experiment. Warren asked subjects to report whether they saw one or two objects and did not directly assess the perception of motion. We replicated Warren's experiment using his figures but also asked subjects to rate the smoothness of motion and to describe the type of motion. We obtained frequent reports of motion of disparate, nontransformable figures. Surprisingly, after making this correction in Warren's experiment, we also found that transformability as well as "featural similarity" can affect the type and smoothness of the illusory motion.

Discrimination Learning↗
PubMed1977

A phantom-motion aftereffect.

Motion aftereffects, typically found to result only from localized retinal stimulation, were obtained within regions of the visual field that had not been stimulated by moving contours. "Phantom" stripes are seen moving through a physically homogeneous (empty) region of the visual field when vertical stripes move above and below that region. Immediately afterward, stationary stripes in the previously empty region appear to move in the opposite direction. This phantom-motion aftereffect provides a novel instance of the way global structure affects processes that have been assumed to be influenced only by simpler local spatial and temporal variables.

Afterimage↗
PubMedDate not supplied

The effect of comparison films upon resident interpretation of pediatric chest radiographs.

Radiology residents beginning training or at the end of the first, second, or third year of training served as observers in a study of the effect of previous or comparison radiographs upon the interpretation of current pediatric chest films. For physicians early in residency, a substantial improvement in detection accuracy occurred when a prior normal film was presented with each examination. Facilitation of a lesser magnitude was obtained for specific diagnosis (classification) of lesions. Thus, while normal comparison films may help reveal to the newer resident that an abnormality exists, it does less to reveal the nature of that abnormality. For physicians late in residency, the same difference in detection accuracy between groups was obtained, but the magnitude of the difference was quite small. However, substantially higher accuracy of specific diagnosis resulted when comparison films were available. While neither normal nor abnormal comparison films markedly changes the accuracy of detection by advanced residents, both improve diagnosis.

Educational Measurement↗