Virtual reality allowed to emotionally experience a virtual promenade through de-contextualized environments formed by three consecutive nuclei whose architectural features varied progressively. This allowed us to isolate the effects generated by purely architectural factors on subjects’ affective states, founding that negative-valenced feelings were generated by narrowing the sidewalls, increasing the windows height or increasing/decreasing the ceiling height. In the first two cases, such modulations also generated a significant increase of the perceived arousal. Results of rmANOVAs and cluster analysis revealed that the architectural feature that more strongly affected valence and arousal ratings was the side walls distance. Finally, we found that our architectural spaces generated either pleasant and low arousing states or unpleasant and high arousing states, possibly arguing that de-contextualized architectural forms may be associated with relaxing or anguishing spaces, and rarely with pleasant and exciting spaces or unpleasant and calming ones.
Our results showed a preference for the subjects to experience the virtual promenade within wide spaces rather than enclosed ones, arguing that the progressive reduction of the surrounding space was perceived as a constriction, thus leading to uncomfortable states of unpleasantness and high arousal 20,21. This is in line with enclosure and permeability theories, according to which enclosed spaces, characterized by a reduced possibility to move-through and see-through, are associated with uncomfortable states 24. Previous studies also revealed that 2D stimuli of enclosed spaces were more likely to generate fear sensation, avoidance decisions and judged as less beautiful relative to open spaces 2,3. Furthermore, enclosed spaces are associated with situations perceived as less controllable, avoided by human beings because increasing the stress level for their inhabitants 13. Reasons can be found in survival motivation since enclosed spaces do not typically provide any possible way out 24,25.
Analogously, the virtual promenade characterized by decreasing ceiling height produced a progressive reduction of the surrounding space thus leading subjects to report unpleasant judgments. We found a preference peak for constant ceiling height of 4 m, resembling results in favour of built environments with 3 m ceiling height which fosters exploration and visuospatial attention 3,4,26. Such 1 m difference with respect to the reported literature could be due to general misperception effects generated by virtual reality 27. In fact, recent findings suggest that egocentric distances in virtual environments are estimated as the 75% of the modelled virtual distance 28. Instead, the over-increasing in the height of the ceiling led to perceive the architectural space as less pleasant, as also reported by Baird and colleagues 26, possibly due to a decreased perception of the spaciousness 15.
We report that virtual promenades with increasing height of the windows generated unpleasant and high arousing judgments. In such architectural spaces, light penetrated from progressively higher and less accessible points, leading subjects to move towards less enlightened areas and where a possible outdoor view was more difficult to access. Previous research claimed that these aspects are fundamental for the wellbeing of the inhabitants29. On the one hand, enabling the sunlight to penetrate the architecture through the windows is essential to promote circadian rhythms, directly affecting human health and wellbeing. Acosta and colleagues 6 showed that windows size, position, and orientation significantly modulated the amount of sunlight within classrooms, thus varying the circadian stimulus for adolescents. On the other hand, access to outdoor views was found to reduce the stress level at the work office 30, to provide restoration at home 31, and benefits to post-operative patients during recovery 32. Furthermore, the presence of windows is also typically associated with an increased perception of the spaciousness of the environment 7,33. In line with such findings, our results emphasize that placing the windows closer to the subject height produced a more pleasant experience with lower values of arousal possibly due to an increased perception of the spaciousness 11,34,35.
The colour modulation of the environments did not affect neither valence nor arousal judgments at the end of the dynamic architectural experience. The specific bluish and reddish colours were selected to generate cold and warm sensations recalling different materials such as concrete and wood, respectively. To deeper investigate how the chromatic aspect of the environment modulates the individual emotional state, we need to consider additional chromatic characteristics, such as different value of hue, intensity and saturation.
Our results suggest that modification of forms produces a variation of the extra-personal space which the subject can visually explore and move within, thus affecting the perception of spaciousness. Since it is known that space coding relies on both visual as well as motor circuits 36–39, we may hypothesize that the emotional experience generated by the dynamic perception of progressive variation of architectural features could exploit the neural circuitry composed by parietal and premotor areas devoted to controlling and planning of voluntary movements 40–43.
This study demonstrates that virtual reality technologies allow to evaluate emotional perception of people during the progressive variation of architectural features within de-contextualized environments, contributing to foster a human-centered approach to design where mental state of people is fundamental for the creation of novel spaces. This knowledge will assist the design of built settings with features coherent with the social events expected to occur inside them (e.g., collaborative and social interactions in the workplace, patient-staff interaction in healthcare settings, formation of social ties in public spaces). A better understanding of how different architectural features influence and possibly support social interactions will also bring us a step closer to designing for neurodiversity and social sustainability.