Visual angle as determinant factor for relative distance perception

Visual angles are defined as the angle between line of sight up to the mean point of a relative distance and the relative distance itself. In one experiment, we examined the functional aspect of visual angle in relative distance perception using two different layouts composed by 14 stakes, one of them with its center 23 m away from the observation point, and the other 36 m away from the observation point. Verbal reports of relative distance were grouped in 10 categories of visual angles. Results indicated visual angle as a determinant factor for perceived relative distance as observed in the absence of perceptual errors to distances with visual angle equal or larger than 70 degrees that could be attributed to a combination of sources of visual information. Another finding showed a possible intrusion of non-perceptual factors (observer’s tendencies), leading to compressed estimates to relative distances with visual angles smaller than 70 degrees. In general, research on visual perception of space is accomplished on homogeneous spaces, characterized by presentation of isolated stimuli in front of observers in order to investigate functional aspects of visual space. Homogeneous environments are not representative of real world conditions which can be better represented by visual scenes. Visual scenes are composed by a set of objects, whose locations are defined by a coordinate system which is independent of observer position. Biederman (1972) stated that one can produce two different conditions