Terrestrial-Passage Theory: Failing a Test

Perception ◽  
10.1068/p6162 ◽  
2009 ◽  
Vol 38 (5) ◽  
pp. 740-747
Author(s):  
Charles F Reed ◽  
Elizabeth A Krupinski

Terrestrial-passage theory proposes that the ‘moon’ and ‘sky’ illusions occur because observers learn to expect an elevation-dependent transformation of visual angle. The transformation accompanies daily movement through ordinary environments of fixed-altitude objects. Celestial objects display the same visual angle at all elevations, and hence are necessarily non-conforming with the ordinary transformation. On hypothesis, observers should target angular sizes to appear greater at elevation than at horizon. However, in a sample of forty-eight observers there was no significant difference between the perceived angular size of a constellation of stars at horizon and that predicted for a specific elevation. Occurrence of the illusion was not restricted to those observers who expected angular expansion. These findings fail to support the terrestrial-passage theory of the illusion.

Author(s):  
Maria Olga Kokornaczyk ◽  
Stephan Baumgartner ◽  
Lucietta Betti

Background: The droplet evaporation method (DEM) has been recently proposed as a possible tool to test the efficacy of ultra high dilutions (UHDs) [1]. Here we applied the same methodology consisting in the evaporation of droplets from leakages obtained by placing wheat seeds in UHDs to test whether DEM patterns vary in function of the tested treatment: Zincum metallicum 30c (ZM), lactose 30c as dynamized control (L), and unsuccussed, undiluted water as negative control (C). Since our previous study [1] showed that there is a significant increase in the UHD action in the stressed model, with respect to the non-stressed one, also in the present experiment we tested ZM, L and C on both stressed (s-seeds) and non-stressed wheat seeds (ns-seeds). Aims: The aim of the experiment was to test whether treatments ZM, L, and C applied on ns- and s-seeds influence the DEM pattern characteristics. Materials and methods: Whole, undamaged wheat seeds (Triticum aestivum cv. Inallettabile, harvesting year 2010) were used for the experiment, following the experimental protocol described in [1]. The distinction between s- and ns-seeds is based upon different storing conditions from the harvest until the analysis day: the ns-seeds were kept in controlled conditions at 5°C and in the dark, whereas the s-seeds were kept in lab at varying temperature, humidity and light conditions. As far as treatment preparation is concerned, ZM and L were obtained from triturations 3c (received from the Federal University of Rio de Janeiro) by vertical mechanical succussions and following dilutions; negative control (C) was ultra-pure water from the same water batch used for dilutions. The experiment was repeated on 6 days within one month; each seed lot (ns- and s-seeds) was analyzed on 3 different days (s-seeds on 10th, 11th and 24th February 2014 and ns-seeds on 12th, 26th February and 3th March 2014), with three treatment-replicates for ZM and L and two for C, three repetitions for each treatment-replicate and 5 droplets per repetition (360 patterns for each seed lot). The complexity degree of polycrystalline structures obtained from the evaporating droplets was measured by means of the ImageJ software [2] by calculating their local connected fractal dimensions (LCFD). The data on moon phase, moon position and moon distance from Earth at the beginning of each evaporation process were collected from the online tool virtuelles Telescope [3]. All data were processed by a three-way ANOVA at a significance level of p ≤ 0.05. Correlations between the moon data and LCFD were evaluated by r Pearson coefficient. Results: The effect of the treatment on LCFD values of DEM patterns was significant only in the stressed model: ZM showed a crystallization inhibiting action vs. C on all 3 analysis days, whereas a significant difference between ZM and L could be observed only on first and third analysis day (Fig 1a). ANOVA analysis showed that the overall LCFD means for the s-seed lot differed significantly between each other: 1.33 (a) for C, 1.26 (b) for L, and 1.19 (c) for ZM. Moreover, the LCFD values of both seed lots showed a strong day factor influence. A possible explanation of this finding might be the influence of the moon (position, phase, and distance from Earth) on the crystallization process: strong correlation between the LCFD of the patterns and moon data were found (r values were from -0.72 to -0.97). Figure 1: Graphical representation of the mean local connected fractal dimension values (LCFD) of droplet evaporation patterns obtained from stressed and non-stressed wheat seeds following treatments with Zincum metallicum 30c (ZM), lactose 30c (L), and unsuccussed/undiluted water (C). Discussion: The present study confirms a pre-sensitization effect towards UHD action in stressed models: a significant inhibiting effect of ZM 30c was found in all experimentation day. Furthermore, the strong correlations observed between the LCFD values and moon data indicate that the complexity of polycrystalline structures from evaporating droplets of wheat seed leakages might be affected by tidal forces. Since DEM needs to be standardized, these correlations can be considered only simultaneous and not causal, however their strength gives good reasons for further studies. Conclusions: The results of the present pilot-study seem to encourage further DEM experiments on s-seeds following UHD treatments. For further confirmation of the inhibiting effect of ZM on s-seeds, germination tests should be planned. Finally, the performance of DEM experimentations during days and hours with equal tidal influence on gravity might be helpful for the reduction of the day factor. Keywords:Ultra high dilutions, droplet evaporation method, patterns, Zincum metallicum


Author(s):  
Sidney L. Smith ◽  
Benjamin C. Duggar

Twelve four-man groups searched and counted visually displayed items. In one session, they used a large display shared in common by the group members; in another session, separate smaller displays were viewed individually. Information was presented under conditions of equal visual angle, so that these two display modes were logically equivalent. Performance was 15 percent faster with the large group display than with the small individual displays. There was no significant difference in error frequency. Some subjects preferred the large display, some the small. In a supplementary study, running individual subjects rather than groups, there were no differences in speed or accuracy between the display modes. This suggests that the difference in group performance time resulted from some facilitating effect of the shared display on the process of group interaction.


2021 ◽  
Vol 2 ◽  
Author(s):  
Sebastian Oberdörfer ◽  
David Heidrich ◽  
Sandra Birnstiel ◽  
Marc Erich Latoschik

Impaired decision-making leads to the inability to distinguish between advantageous and disadvantageous choices. The impairment of a person’s decision-making is a common goal of gambling games. Given the recent trend of gambling using immersive Virtual Reality it is crucial to investigate the effects of both immersion and the virtual environment (VE) on decision-making. In a novel user study, we measured decision-making using three virtual versions of the Iowa Gambling Task (IGT). The versions differed with regard to the degree of immersion and design of the virtual environment. While emotions affect decision-making, we further measured the positive and negative affect of participants. A higher visual angle on a stimulus leads to an increased emotional response. Thus, we kept the visual angle on the Iowa Gambling Task the same between our conditions. Our results revealed no significant impact of immersion or the VE on the IGT. We further found no significant difference between the conditions with regard to positive and negative affect. This suggests that neither the medium used nor the design of the VE causes an impairment of decision-making. However, in combination with a recent study, we provide first evidence that a higher visual angle on the IGT leads to an effect of impairment.


1985 ◽  
Vol 40 (1) ◽  
pp. 161-167 ◽  
Author(s):  
G. P. Pearce ◽  
P. E. Hughes

ABSTRACTTo examine the influence of boar exposure environment and daily movement on the efficacy of boar-induced precocious puberty in the gilt, 60 Large White × (Large White × Landrace) prepubertal gilts from 12 litters were randomly allocated within litter to five treatment groups of six, in two replicates, at 145 days of age. Treatments were (1) control (no movement or boar exposure), (2) gilts moved to a boar pen and exposed to a mature boar, (3) gilts moved to a different pen and exposed to a boar, (4) gilts moved to a different pen only, (5) gilts moved to a vacated boar pen. Treatments occurred for 30 min/day for 75 days, or until pubertal oestrus was observed. Gilts showing pubertal oestrus were removed and slaughtered. Ovaries were examined to confirm reproductive status. Gilts failing to exhibit oestrus by 240 days of age were slaughtered and nominally ascribed a pubertal age of 245 days. Age at puberty was significantly earlier (P < 0·001) in treatments 2 and 3 involving boar exposure than in treatments 1, 4 and 5 not involving boar exposure. No significant difference was observed in the median gilt age at puberty between the two forms of boar exposure used in this experiment. Thus the efficacy of the boar effect does not appear to be significantly affected by the environment in which exposure to the boar takes place. Additionally, it is suggested that the stress of a daily pen change is insufficient to stimulate precocious puberty in gilts in the absence of boar contact.


Perception ◽  
1995 ◽  
Vol 24 (6) ◽  
pp. 623-630 ◽  
Author(s):  
Corinne Cian ◽  
Dominique Esquivié ◽  
Pierre Alain Barraud ◽  
Christian Raphel

The visual angle subtended by the frame seems to be an important determinant of the contribution of orientation contrast and illusion of self-tilt (ie vection) to the rod-and-frame effect. Indeed, the visuovestibular factor (which produces vection) seems to be predominant in large displays and the contrast effect in small displays. To determine how these two phenomena are combined to account for the rod-and-frame effect, independent estimates of the magnitude of each component in relation to the angular size subtended by the display were examined. Thirty-five observers were exposed to three sets of experimental situations: body-adjustment test (illusion of self-tilt only), the tilt illusion (contrast only) and the rod-and-frame test, each display subtending 7, 12, 28, and 45 deg of visual angle. Results showed that errors recorded in the three situations increased linearly with the angular size. Whatever the size of the frame, both mechanisms, contrast effect (tilt illusion) and illusory effect on self-orientation (body-adjustment test), are always present. However, rod-and-frame errors became greater at a faster rate than the other two effects as the size of the stimuli became larger. Neither one nor the other independent phenomen, nor the combined effect could fully account for the rod-and-frame effect whatever the angular size of the apparatus.


2000 ◽  
Vol 44 (21) ◽  
pp. 3-419-3-422 ◽  
Author(s):  
Richard P. Grutzmacher ◽  
George A. Geri ◽  
Byron J. Pierce

The ratio (τ) of a moving target's angular size to the rate of change in its angular size can be used by observers to judge the time remaining before they will collide with the target. We consider here whether optical flow information, consistent with simulated observer motion, affects observers' estimates of time-to-contact (TTC). Estimates of TTC were obtained when either the observer approached a stationary target or the target approached a stationary observer. The visual information for τ was the same in both conditions, whereas the visual information for observer self-motion was varied. For the low closing velocities, (3 and 6 eyeheights/sec) there was no significant difference in the estimated TTC for observer motion versus target motion. However, there was a significant difference for the highest closing velocity (12 eyeheights/sec). This result suggests that visual information, specifying self-motion, may be used either in combination with or in place of τ to estimate TTC during simulated locomotion. The present findings have practical implications for both the use of τ in judging TTC and the rendering of terrain texture detail in high-fidelity flight simulators.


2002 ◽  
Vol 25 (1) ◽  
pp. 116-117
Author(s):  
Helen E. Ross

Berkeley and Helmholtz proposed different indirect mechanisms for size perception: Berkeley, that size was conditioned to various cues, independently of perceived distance; Helmholtz, that it was unconsciously calculated from angular size and perceived distance. The geometrical approach cannot explain size-distance paradoxes (e.g., moon illusion). The dorsal/ventral solution is dubious for close displays and untestable for far displays.


Perception ◽  
10.1068/p5513 ◽  
2007 ◽  
Vol 36 (8) ◽  
pp. 1214-1228 ◽  
Author(s):  
Liang Lou

The apparent size of an afterimage viewed from distances between 5 cm and 580 cm was matched to that of a size-adjustable stimulus at a fixed distance (20, 30, 90, and 200 cm). The experiment was conducted under normal indoor illumination with a procedure that facilitated matching for angular size. The matched size was found to increase with focal distance within 1 m and very little beyond 1 m. Similar results were obtained with an equivalent series of real stimuli subtending a constant visual angle. These findings suggest a scaling in perceived angular size in proportion to the oculomotor adjustments for accommodation and convergence. The observations of perceived angular size of the afterimage complement what Emmert's law is meant to describe (perceived object size of the afterimage), even though as the focal distance decreases it may be increasingly difficult to tease out perceived object size and perceived angular size with the matching procedure.


Sign in / Sign up

Export Citation Format

Share Document