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J R Pani

Publications and source records attributed to J R Pani.

4 recordsLinked to original sources
PubMed1994

Spatial reference systems in the comprehension of rotational motion.

In certain simple rotations of objects, the orientation of the axis and planes of rotation can determine whether people are able to visualize the motion or perceive it as simple and coherent. This finding affords the opportunity to investigate the spatial reference systems used to define the orientation of the axis and planes of rotation. The results of two experiments suggest that the permanent environment is the primary reference system, apart from the rotating object, used for this purpose. Subjects also were able to use a local spatial environment to determine the orientation of the motion; some subjects were particularly adept at this. The viewer perspective, in contrast, was irrelevant as a reference system in these experiments. These results argue strongly for the primacy of environmental reference systems in the perception and imagination of orientation and extend the set of findings common between the comprehension of rotational motion and orientation-sensitive form perception.

Environment↗
PubMed1994

The generalized cone in human spatial organization.

The generalized cone is one of the newer concepts useful for describing spatial structures, and it has become popular as a volumetric primitive in models of object recognition. Apart from this use of the concept (or perhaps underlying it), the generalized cone can be considered a species of spatial regularity. In the general definition of symmetry as invariance across transformation, the generalized cone is a combination of translation and dilation symmetry. In such symmetry, there is homogeneity both of the slants of edges and surfaces of an object about an axis and the radial positions of these features about the axis. The results of two research projects are reviewed suggesting that the generalized cone is useful in human spatial organization. In the first instance, each of the three simpler regular polyhedra, the Platonic Solids, are easiest to perceive and imaging when they are organized as generalized cones. In the second instance, people imagine simple rotations best when the symmetric space that would be traced by the motion is aligned with salient spatial reference systems.

Form Perception↗
PubMed1993

Limits on the comprehension of rotational motion: mental imagery of rotations with oblique components.

Mental imagery of rotational motion across variation in the orientation of a square to an axis of rotation, the orientation of the axis to the environment/viewer, and the starting orientation of the rotation were investigated in three experiments. The experimental method included specifying the particular rotations that subjects should consider and obtaining exact predictions of the outcomes of the rotations. When the square was normal to the axis and the axis was normal to the environment/viewer, performance was excellent. When either of these relationships was oblique, performance was quite good. When both of these relationships were oblique, nearly every subject made large errors on every problem. The difficulty of the double-oblique rotations was reduced when the initial orientation of the square was not canonical. Current views of the comprehension of rotational motion are discussed. It appears that the comprehension of rotational motion can be understood as an organizaiton of the symmetric space traced out by the motion. People succeed in organizing this space when it is aligned with a principal spatial reference system.

Adult↗