Relative distance of lights: An extension of Bugelski’s findings

Abstract

Roelofs and Zeeman (1957) showed that a stimulus presented to the nasal part of the eye was seen as closer to the S than the stimuli presented to the temporal part of the eye. Dunn, Gray, and Thompson (1965) showed that the height of an object in the visual field was a critical variable in its perceived distance relative to another object in the field. This result is also recorded by Roelofs and Zeeman (1957) and by Epstein (1966). The most usual fmding has been that the higher of two stimuli is seen as farther away. In none of these cases has there been control for position of the S's eye in the field. Dunn (1967) attempted to vary the direction of regard, but was unable to find any differences. However, he used transparencies that varied in their orientation to the 8 as a function of the direction from which the 8 looked at them. The findings in all cases supported the earlier studies. The higher end of the transparency was perceived as the farther end. Bugelski (1967) obtained results that differed from the above studies. He used two lights, separated by 2 deg, in an otherwise dark field. The 8 adjusted the lights to make them appear equal in distance. All but two Ss adjusted the lights so that the higher of the two lights was placed closer. Under another condition, two stimuli were presented to the Ss on the same horizontal, also separated by 2 deg. There was no significant statistical difference between the mean placements of the two lights. Bugelski postulated that the vertical effect would probably not occur with separations of much over 2 deg.The disparity between the above fmdings raises several interesting questions. First, did the free movement of the S's head allowed by Bugelski enter into the results? Second, was the direction of regard with respect to the stimulus display a factor? Third, was the small visual angle a factor, as suggested by Bugelski? Fourth, was the fact that binocular vision was used by the Ss a significant factor? The following study attempts to answer the questions raised above. The S's head was fixed with a chin-rest in order to avoid head movement. He fixated upon a center fixation light to direct his direction of regard. Vision was monocular and the angle between the stimuli was much larger than that used by Bugelski. The apparatus was so constructed that direction of regard could be varied while maintaining rigid relationships between important aspects of the stimulus array. METHOD SubjectsThe Ss were two sophisticated male and female undergraduate psychology majors. Their training consisted of several months of making judgments in various relative depth situations, not associated with the apparatus used in the following experiment. Both Ss had considerable experience in maintaining fixation upon a flxation light. Neither S was familiar with Bugelski's findings. ApparatusThe S viewed the stimuli through a l-cm pupil from a distance of 1 em. His chin rested on a chin-rest that held his head motionless. Three I~-in. pipes, painted on the inside with low-reflectant black paint...

Comparison of two indicators of perceived egocentric distance under full-cue and reduced-cue conditions.

“…Because ground-level targets vary systematically in angular elevation as egocentric distance increases, angular elevation uniquely specifies the distance of such targets and thus could serve as a useful cue to egocentric distance. It is well established that when two targets are presented simultaneously in an otherwise dark environment, their relative heights in the visual field can influence judgments of their relative distance (Bruno & Cutting, 1988; Bugelski, 1967; Dunn, 1969; Dunn, Gray, & Thompson, 1965; Epstein, 1966). Wallach and O'Leary (1982) manipulated angular elevation with an optical device and investigated the influence angular elevation had on absolute size judgments of paper rectangles in a well-lit room.…”

Effects of Motion Parallax and Perspective Cues on Perceived Size and Distance

“…Previous results suggested that the horizon-ratio relation was an effective but weak cue for relative size (Bingham 1993;Dixon et al 2000) and there were some limitations in the effective range of this cue (Rogers 1996;Bertamini et al 1998;Wraga and Proffitt 2000). For distance, the h 2 ah 1 ratio was called a cue of height in the field, and previous studies have shown the effectiveness of this cue (Dunn et al 1965;Epstein 1966;Dunn 1969;Bruno and Cutting 1988). For our experimental stimuli, because the two objects were always presented below the horizon and were always the same retinal size, the horizon-ratio relation should be equal geometrically to the height in the field.…”