Visual illusions in geology
Examples of visual illusions in the laboratory are well documented, but what about illusions that occur during field observation of geological structures? In this article I discuss a study involving geologists and non-geologists and define some of the problems that may arise during geological field and laboratory work.
Geometrical illusions in solid objects under ordinary viewing conditions
The Müller-Lyer and Ponzo illusions were obtained under free binocular viewing of three-dimensional objects, and the function relating magnitude of illusion to fin angle, characteristic of converging-line versions of the Müller-Lyer pattern, was closely paralleled by volumetric (three-cone), line-free objects (but not with an erect, planar “walk-through” construction and moving observers). Illusions cannot be dismissed as artifacts of static, impoverished viewing, therefore, but must be explained within any general theory of perception. Perspective explanations have difficulties with such three-dimensional manifestations, and seem completely inapplicable to our further finding that approximately the same amount of illusion occurred in objects and patterns with no oblique lines or edges. Confusion or averaging theories, not themselves tested here, remain unthreatened by these data.
Fear of Crime in Relation to Three Exterior Site Features
This article examines fear of crime in relation to exterior site features on a college campus. The authors propose and test a theoretical model that posits that places that afford offenders refuge, and victims limited prospect and escape, will be seen as unsafe. In three studies, the authors observed behavior, obtained responses to site plans and on-site responses to perceptions of safety in relation to exterior campus areas that varied in prospect, refuge, and escape. The findings confirmed that fear of crime was highest in areas with refuge for potential offenders and low prospect and escape for potential victims. In places such as campuses, which have pronounced fear of crime, designs that manipulate prospect, refuge, and escape could reduce the fear of crime, as well as opportunities for crime.