Permeability theory and Palace Athena.

Permeability theory suggests that safety in environments depends on how far and how easily one can perceive or move through environments. Parts of environments that limit perception or retard locomotion elicit impressions of being enclosed, so properties of environments that influence perceived enclosure are important in permeability theory. One prediction of permeability theory is that the more permeable the boundary, the less enclosed the region within that boundary will seem to be. Another prediction is that boundary depth will have little influence on perceived enclosure. These predictions were tested in the venue of Greek temples. 30 participants were tested (14 men, 16 women; M age = 40 yr.), who rated perceived enclosure for 18 stimuli. The stimuli were constructed using a virtual scene from the Tholos in Delphi with the positions of the columns forming the boundaries. The boundaries were designed to have different levels of permeability and depth. Data were analyzed in terms of effect sizes and focused comparisons. Results indicated that perceived enclosure was most strongly influenced by the visual permeability of the boundary, while depth of boundary had a much smaller effect on perceived enclosure.

Surf & turf: effects of ground substrate on perceived threat, enclosure, and perceived walkability.

Permeability theory suggests that perceived enclosure should be mitigated by the walkability of the surface underneath a person. This prediction was tested by obtaining ratings of perceived threat, perceived walkability, and perceived enclosure for five types of surfaces: pavement, grass, sand, water, and rocks. There were three experiments, 20 stimuli, and 112 participants. Perceived threat and perceived enclosure were highly correlated, as were perceived walkability and type of surface underfoot. Environments in which the surface underneath were difficult to walk over were perceived as being more enclosing and more threatening than surfaces that were easy to walk over. The findings all supported a priori hypotheses generated from the permeability theory of environmental perception and preference.

How distance mitigates perceived threat at 30-90 m.

It has previously been shown that distance mitigates the extent to which non-verbal cues such as direction of eye gaze, facial expression, sex, and posture communicate threat. However, the range of distances investigated has been limited to 45m or less. Theory predicts that there should be effects at distances up to 100 m. This article reports findings on how strongly sex and posture communicate threat at ranges up to 90 m. Results suggest that the distance where non-verbal cues cease to communicate threat is in the range of 30-90 m.

A walk down the block: spatial and temporal parameters of aesthetic judgments about ordinary streetscapes.

An experiment is reported based on 12 streetscapes and 25 participants on how five spatial/temporal factors influenced aesthetic judgments about ordinary streets. Overall, aesthetic judgments were more strongly related to the temporal variables of total time, stationary time, and decision time rather than the spatial variables of path length or number of turns made to obtain different views. It is suggested that fancy simulations or detailed scrutiny are probably not needed to evaluate streetscapes as seen by people in the street.

Distance mitigates perceived threat.

It has previously been shown that distance mitigates the extent to which visual cues convey perceived threat. It was hypothesized that the visual cues of eye contact, sex, facial expression, and posture would all convey threat. It was further hypothesized that the effects of visual cues on the perception of threat would decrease with distance, but the extent of those decreases was unknown. In the present study, participants were exposed to images of people situated in a physical venue. The images were created to exhibit combinations of the levels of the four visual cues (yes or no for eye contact, male or female for sex, hostile or benign for facial expression, and hostile or benign for posture). Participants were given an opportunity to record how threatening the images of the people seemed to be. The results supported all a priori hypotheses regarding the effects of the visual cues. The results also generated estimates of the distances at which those visual cues ceased to convey threat.

Effects of boundary height and horizontal size within boundary on perceived enclosure.

The permeability theory of environmental design predicts that perceived enclosure will be more strongly related to boundary properties such as height as opposed to the size of a horizontal area within a boundary. An experiment on perceived enclosure, provided by 24 participants on 12 spaces in a park, indicated that enclosure correlated at .85 with boundary height and -.60 with horizontal area. These results were as predicted by permeability theory.

Use of static and dynamic media to simulate environments: a meta-analysis.

This article is a review of studies on how strongly responses from static media (such as color slides) and dynamic media (such as virtual reality models) compared to onsite evaluations or to each other. Eighty-four empirical findings were found. 6,323 participants and 967 environments were included in the review. The overall correlation of subjective responses obtained either onsite or by viewing static color simulations was r = .86. The overall correlation of subjective responses obtained either onsite or by viewing dynamic simulations was r = .83. The overall correlation of subjective responses obtained either from static or dynamic media was r = .82. It is suggested that both types of simulation generate statistically equivalent results and so a choice of simulation media should be based on efficacy rather than concerns about validity.

Some findings on prospect and refuge theory: II.

This article presents four new studies on the efficacy of predictions based on prospect and refuge theory and summarizes the results over eight studies. New data covered 49 participants and 36 environments. The eight studies included in the summary covered 144 participants and 80 widely diverse environments (Japanese Tatami rooms, Western rooms, porch, meadow, neighborhood commercial, shopping mall, vacation landscapes). Data were available for hypotheses about five factors: prospect, refuge, light, venue, and spatial transition. Efficacy was represented by correlations for the levels of the factors with responses of preference or comfort. Overall, venue was the most efficacious factor (r = .42, 95% CI = .14, .64). Efficacies for the other factors were very near zero. It is suggested that a considerable amount of additional formal inquiry be conducted before assuming the utility of prospect and refuge theory.

Some findings on prospect and refuge: I.

Prospect and refuge theory suggests that preferences for environments are based on prospect (the unimpeded opportunity to see) and refuge (the opportunity to hide). This article reports two experiments on how well four factors derived from prospect and refuge theory predicted responses of comfort or liking. The factors were prospect (depth of view), refuge (presence of protective regions in front of the observer or occluding edges that might indicate possibilities of escape), direction of light (either front lighting or back lighting), and venue (natural or built environments). Exp. 1 had 16 landscape scenes and 29 participants; Exp. 2 had 16 landscapes, 14 rooms, and 18 participants. Empirical support was obtained for the claim that people will like gazing out over scenes of distant mountains. For venue, built scenes were preferred over scenes of nature. Results for refuge were ambiguous, and those for di rection of light were nill.

Entropy and environmental mystery.

Two studies are reported regarding the effects of entropy, lighting, and occlusion on impressions of mystery in physical environments. The theoretical context of this study was the "informational theory" of environmental preference, which, among other claims, holds that mystery can be measured by the extent to which people perceive a promise of more information if they move deeper into an environment. Entropy, in the context of this article, is visual diversity as measured using information theory. Mystery was measured by a semantic differential scale. The definition of mystery was left up to each individual participant. Entropy of occluded objects was used to obtain an objective, experimentally manipulatable and operational definition of "promise of more information." Exp. 1 had 12 stimuli and 15 participants. Exp. 2 had 12 stimuli and 16 participants. Entropy of occluded objects ranged from 0 to 6 bits. Entropy of occluded objects was used to measure the promise that there would be more information if one moved deeper into an environment. Overall, amount of light had the strongest effect on responses of mystery (r = -.63, darker was more mysterious), followed by occlusion (r = .26, occluding objects made a scene seem more mysterious), and by the promise of more information if one moved about in the scene (r = .13), the more entropy in occluded objects, the greater the impression of mystery). The theoretical contribution of this work is that a relationship between subjective impressions of mystery and an objective measure of "promise of more information" was found.

Surface location and enclosure.

This research addressed the issue of whether impressions of enclosure were more strongly influenced by amount of view covered by vertical boundaries (H1) or the presence of a boundary overhead (H2). There were three studies with totals of 48 stimuli and 142 respondents. Stimuli were balconies, swamps, and space stations. Effect sizes were reported for variables of boundaries below, in front of, and at the observers' sides, as well as amount of view covered by any boundary regardless of location with respect to the observer. Judged enclosure correlated at r =.80 for amount of view covered by vertical boundaries and r =.42 with the presence or absence of boundaries overhead, indicating that enclosure is more strongly related to vertical rather than overhead boundaries (alpha< .001).

Interior prospect and refuge.

Prospect and refuge theory has usually been applied to landscapes but recent work suggests that it could also be applied to interiors. This article reports two experiments, covering 14 environments and 97 respondents, in which five hypotheses regarding prospect, refuge, and comfort were tested: H1: the transition from small, dark, and low to large, light, and high and vice-versa; H2: the transition from dark to light vs vice-versa; H3: the transition from low to high vs vice-versa; H4: the transition from small to big horizontally vs vice-versa; and H5: width. Results varied. The effect of width on comfort was substantial (r = .35); effects for the other hypotheses were either subtle or contrary to expectations.

Elongation and enclosure.

Previous work suggested that elongation, horizontal area, and the boundary material might influence impressions of enclosure. This article describes an experiment in which these three factors were crossed. Ratings of open/enclosed by 15 respondents on 16 plazas indicated that the elongation ratio (range: 1:1 up to 1:1.8) had the strongest effect on impressions of enclosure (18% of variance). Horizontal area (12.25 m2 vs 49 m2) area accounted for 3% of variance. The amount of variance attributable to boundary material (plants vs walls) was an order of magnitude smaller (0.3%).

In search of dominance: the case of the missing dimension.

Some previous researchers have found that affect can be described in terms of two dimensions (pleasure and arousal), while others have noted three dimensions are needed (pleasure, arousal, and dominance). The competing claims were tested by creating stimuli with factors previously demonstrated to elicit responses of arousal or dominance, asking respondents to rate the stimuli, and contrasting correlations between ratings and the stimulus factors. Under the two-dimensional theory, the planned contrasts should be zero, while under the three-dimensional theory, the planned contrasts should be nonzero. Results supported the three-dimensional model.

Perceived enclosure of space, angle above observer, and distance to boundary.

Most previous research suggests that the horizontal size of a space has a strong effect on the perception of enclosure, but Hayward and Franklin reported in 1974 that the main determinant of perceived enclosure was the ratio of boundary height (H) over the distance to boundary (D) rather than just the boundary height per se or distance per se. We attempted replication of that finding. Students (41 male, mean age=24.7 yr., SD=7.7) rated 16 images on a scale of open/enclosed. There was a strong effect on impressions of enclosure for angle above observer (r = .91), and this effect was larger than the effect of height (r = -.17), but there also was another strong effect for distance (r = -.68). Moreover, the effect of distance was dependent on angle above observer (r = -.52). Thus, partial replication was achieved, and a new relationship between the geometry of environments and perceived enclosure was identified.

Permeability and environmental enclosure.

Theories by J. J. Gibson and H. Hediger suggest that environmental enclosure is important. Re-examination of their work suggests that judged degree of enclosure might be influenced by permeability of spatial regions. This study reports effects on judgments of enclosure by permeability and two other factors, horizontal size of rooms and heights of walls. 64 respondents rated 24 scenes on the criterion of enclosure. Pearson correlations for judged enclosure with the three factors were .68 for height, -.51 for permeability, and -.31 for horizontal size. Interactions between the factors had very small effects on judged enclosure.

Entropy, visual diversity, and preference.

The author reports relationships between subjective impressions of visual diversity or pleasure with statistical entropies of stimuli. The stimuli were 34 rows of houses that varied in color, scale, and shape, or in shape and articulation. Entropies ranged from 0.0 to 5.6 bits. Fifty-seven participants rated the stimuli on scales of pleasant/unpleasant and uniform/diverse. The relationship between rated diversity and entropy was strong and linear. The relationship between rated pleasure and entropy was either linear or asymptotic, but no evidence was found for an inverted U relationship.