Brave upside down world: Does looking between the legs elongate or shorten the perceived distance

The aim of this research was to give further evidence for the influence of vestibular and proprioceptive information on distance perception, and to verify how perceived distance changes if we use matching versus verbal judgment task. That is, the aim was to investigate how perceived distance changes when we bend over and look between the legs. The experiment was performed on a daylight open field (full-cue situation), with 20 participants, high school students from the Petnica Science Center. Participants had the task to match distances of two stimuli, one of which was in front of them at eye level, whereas the other was behind them, and they could observe it by bending their body forward and looking between the legs. Stimuli were 7cm*5cm large, and rectangular in shape. Results have shown that perceived distance changes in such a way that distances observed between the legs are perceived as longer than distances observed from an upright position. This difference in perceived distances exists only for larger physical distances (3m and 5m), but not for smaller physical distances (1m). Results coincide with our previous findings which indicate that vestibular and proprioceptive information change elongates perceived distance. On the other hand, the results contradict some findings gained in experiments in which the verbal judgment task was used. These contrary results probably appear because the verbal judgment task leaves more space for higher cognitive processes to be involved.

Modeling Verbal Judgements

In the previous chapter we have outlined the basic structure of a verbal model and its main components: Judgments, rules and qualifiers. This chapter proposes a model, called the dual truth model, to represent verbal judgments through fuzzy logic. Furthermore, the dual truth model permits us to examine more in depth and quantitatively assess the vagueness and ambiguity contained in a verbal judgment. An application of the model to the definition of assessment scale for personnel appraisal is also provided.

Effect of Brightness on Perceived Distance as a Figure—Ground Phenomenon

Two experiments were performed to compare the effects of brightness on perceived distance in the situations in which a target appeared either as figure (experiment 1) or as ground (experiment 2). In experiment 1 the stimulus array consisted of two small homogeneous target regions and a homogeneous surrounding region common to both; in experiment 2 it consisted of two large homogeneous target regions and a textured surrounding region. Subjects were asked to indicate which of the two targets appeared nearer and to make a verbal judgment of perceived depth between them. The results showed that the target having the greater brightness contrast with the surround is apt to be judged nearer when the targets appear as figure, and farther when they appear as ground. These findings support Egusa's hypothesis that the effect of brightness on perceived distance can be attributed to figure—ground differentiation between the target region to be judged and its direct surround.