Window Access to Nature Restores: A Virtual Reality Experiment with Greenspace Views,Sounds,and Smells

Abstract

Exposure to nature can improve psychological well-being such as attention restoration. These restorative benefits may be provided by windows looking onto nature, yet studies on the restorative qualities of windows have largely taken place in calm environments where restoration demands are relatively low. Thus, the restorative effects of windows in busy environments warrant examination. This virtual reality (VR) experimental study measured the restorative qualities of windows with nature views in a busy setting. We exposed 88 undergraduate participants to an open, closed, or no window condition by creating a Computer Automatic Virtual Environment (CAVE)-like VR environment. The participants saw a 6-min wall-projected video of a busy university café along with indoor sounds played in the background and the scent of coffee created by an essential oil diffuser. Birdsongs and dirt smells were added to the open window condition. The Perceived Restorativeness Scale (PRS) and Restoration Outcomes Scale (ROS) were administered after VR exposure. Results showed that compared with no window, the open window was more restorative in terms of the ROS, PRS, and the PRS subscales related to fascination and being away. The closed window was more restorative in terms of the ROS and being away subscale. Unexpectedly, the addition of sounds and smells virtually coming through the open window did not provide restorative qualities beyond what was provided by the closed window. These findings provide suggestive evidence that virtual windows looking onto nature provide restorative effects for people in busy indoor environments.

Introduction

Humans have an inherent connection with nature formed through evolution and adaptation within natural environments (Kellert, 2003; Kellert et al., 1993). The human affinity toward nature is in part demonstrated and reinforced by a wide array of health benefits provided by nature (Victorson, Luberto, & Koffler, 2020; Zhang, Yu, Zhao, Sun, & Vejre, 2020). Increasing evidence suggests that contact with nature benefits stress reduction (Berto, 2014; Bowler, Buyung-Ali, Knight, & Pullin, 2010), mental health (Grassini et al., 2019; Korpela et al., 2017; Tabrizian, Baran, Smith, & Meentemeyer, 2018), and physical health (Browning & Lee, 2017; Hartig, Mitchell, De Vries, & Frumkin, 2014; Kardan et al., 2015).

In particular, the psychological benefits of nature are often explained in light of Kaplan and Kaplan's (1989) attention restoration theory (ART), which posits that nature views can increase human effectiveness through recovering attentional capacity from mental fatigue. Also, Ulrich's (1983) stress reduction theory (SRT) explains the affective and stress-reducing (i.e., reduction in physiological arousal caused by stress) benefits of exposure to nonthreatening nature. Nature exposure is particularly relevant to populations that experience high levels of stress and attentional demands and would benefit from positive distractions and temporary escapes from their immediate circumstances (Kaplan & Berman, 2010; Ulrich et al., 1991).

As recent urbanization and indoor-oriented lifestyles have segregated many people from restorative nature exposure (Cox, Shanahan, Hudson, Fuller, & Gaston, 2018), some of the beneficial pathways can still be activated by alternative forms of engagement with biophilic design, such as through window views (Felsten, 2009; Ulrich, 1984; Yin, Zhu, MacNaughton, Allen, & Spengler, 2018). These can be useful channels through which indoor residents can gain psychological restoration and cognitive distance from stressors in the indoor environment (Masoudinejad & Hartig, 2020).

Previous research suggests that indoor designs with window views of nature might deliver outdoor nature's therapeutic benefits (Chang & Chen, 2005; Jo, Song, & Miyazaki, 2019; Kaplan, 2001; Li & Sullivan, 2016; Masoudinejad & Hartig, 2020; Olszewska-Guizzo, Escoffier, Chan, & Yok, 2018). Both actual windows and their virtual counterparts appear capable of providing psychological benefits (Benfield, Rainbolt, Bell, & Donovan, 2015; Chang et al., 2020; K. Korpela et al., 2017; Kim, Cha, Koo, & Tang, 2018; Masoudinejad & Hartig, 2020; van Esch, Minjock, Colarelli, & Hirsch, 2019; Wohn, Kum-Biocca, Sharma, & Khandakar, 2020). A recent systematic review concluded that viewing simulated or actual natural scenery led to physiological relaxation, as measured by brain and autonomic nervous activation (Jo et al., 2019).

The restorative effects of windows might be enhanced when other sensory modalities relevant for attention restoration are considered, specifically auditory and olfactory stimuli. Nature sounds, like bird songs, usually elicit positive emotional responses (Hedblom et al., 2019a, 2019b; Marselle, Irvine, Lorenzo-Arribas, & Warber, 2016; Ratcliffe, Gatersleben, & Sowden, 2013; Ratcliffe, 2021), and can improve indoor soundscapes by masking unwanted sounds (Coensel, Vanwetswinkel, & Botteldooren, 2011; Hao, Kang, & Wörtche, 2016).

Nature odors are also intrinsic to the experience of being outdoors in nature and have been found to facilitate stress reduction and support mental recovery in nature therapy (Pálsdóttir, Spendrup, Mårtensson, & Wendin, 2021). It is, therefore, not surprising that sounds and smells can improve the restorative effects even of simulated nature exposure (Annerstedt et al., 2013; Kjellgren & Buhrkall, 2010; Press & Minta, 2000; Ratcliffe et al., 2013; Valtchanov, Barton, & Ellard, 2010).

Although windows are discussed in biophilic design for their restorative potential when looking onto nature and for their opportunity for fresh air when open (Xue, Lau, Gou, Song, & Jiang, 2019), we are unaware of studies that have tested the additive restorative effects of restorative nature views from open windows that also allow olfactory and auditory exposures.

Furthermore, most of the studies on the therapeutic qualities of windows have taken place in quiet and calm (i.e., nonbusy) environments where demands for attention restoration are relatively low (Yao, Chen, Wang, & Zhang, 2021). The therapeutic effects of nature exposure through windows employed in biophilic design have rarely been tested in busy settings that teem with distractions caused by noise, movement, and crowds of people. Many indoor common spaces are busy settings where attentional restoration from nature is strongly needed. Busyness of a setting increases the attribute of crowding, which can deprive privacy needed for psychological restoration and impose greater involvement with other people than one desires (Devlin, 2018).

Busy environments are likely to impede the processes of attention restoration by blocking out “soft fascination” elements, such as slow and quiet natural phenomena (Kaplan, 1995), and by hindering cognitive function and work performance (Jahncke, 2012; Jahncke, Hygge, Halin, Green, & Dimberg, 2011). Specifically, sensory overload, which is well studied with respect to unwanted sounds interfering with various activities performed, has been found to precipitate lower ratings of perceived restorative quality of the setting (Dzhambov et al., 2021), impaired cognitive performance (Thompson et al., 2022), and even work-related injuries (Dzhambov & Dimitrova, 2017). Hence, many indoor common spaces are busy settings where attentional restoration from nature is strongly needed.

We designed the following virtual reality (VR) study to address the gaps and potential ambiguity in understanding the restorative effects of open and closed windows with views of nature in busy environments. This preliminary investigation was conducted in a convenience sample of college students similar to past research (Benfield et al., 2015; Felsten, 2009; Lassonde, Gloth, & Borchert, 2012), with the intent of inspiring future research that could directly inform design. In response to a call for research on attention restoration in the environments where people work and recreate (Hartig & Jahncke, 2017), we selected a typical and familiar setting for our sample population: the university student union café.

We hypothesized that open and closed windows looking onto nature would have greater restorative effects than the absence of a window (H1). We further hypothesized that an open window with visual, auditory, and olfactory exposure to nature would have greater restorative effects than a closed window with only visual nature exposure (H2).

Methods

Study design

We employed a three-arm randomized controlled trial to examine the restorative effects of two virtual window conditions compared with a baseline condition with no window (Fig. 1). We assigned participants randomly into three groups treated with VR exposures to a busy café scene with different window conditions, namely no window, a closed window, and an open window. Participants completed the digit span forward (DSF) cognitive task, viewed assigned VR scenes, and rated perceived restorativeness/restoration of the scenes after the VR exposure.

Fig. 1.

Study design. VR, virtual reality.

Participants

The experiment was conducted for two months in two academic semesters: spring and fall 2018. Seven hundred students were invited to participate from an online course, of which 92 agreed to participate (53 in spring and 39 in fall) for extra credit as compensation. Assignment to conditions was randomized before arrival; uneven sample sizes resulted from absences. We specified the desired sample of 30 per condition at 80% power based on a small to moderate effect size (d = 0.32) and research on perceived restoration after virtual nature exposure (Browning et al., 2020a). Complete survey data were available for 88 participants, including 27 assigned to the open window, 27 to the closed window, and 34 assigned to the no window. The study protocol was approved by the University of Illinois at Urbana-Champaign institutional review board.

Materials

Equipment

The experiment was implemented in a laboratory equipped with devices for creating a VR environment (Fig. 2). We adapted the Computer Automatic Virtual Environment (CAVE) protocol that guides projection of screens on a room's walls, ceiling, and floor surrounding the viewer, thus presenting a 270° VR simulation (Cruz-Neira, Sandin, DeFanti, Kenyon, & Hart, 1992). The laboratory had a ceiling-mounted air conditioner with a thermostat that maintained the same room temperature (72°F) and relative humidity throughout all treatment conditions.

Fig. 2.

Laboratory setting with a three-sided CAVE-like VR experience. This research participant is being exposed to the open-window condition (the right side). CAVE, Computer Automatic Virtual Environment.

The room featured two Bose 151 speakers and three Hitachi CP-A100 ultrashort-throw projectors with 1600 × 1200 resolutions facing walls covered with projector screen paint. Two ultrasonic essential oil diffusers (purchased at Aura Cacia, Norway, IA) were used to provide olfactory stimuli.

Videos

A 6-min video was filmed at the university student union café where the participants were enrolled as full-time students and used as the background environment. We chose the video length based on the findings of past research showing when the restorative qualities of virtual nature versus actual nature are similar (Browning et al., 2020a; Chirico & Gaggioli, 2019; Hedblom et al., 2019a; Palanica, Lyons, Cooper, Lee, & Fossat, 2019). The café was captured with two Sony Handycam HDR TD30V camcorders oriented at 90° angles to one another. These scenes were projected on the front and left walls of the laboratory from the participant's viewpoint. One of three forms of a brick wall was projected on the participant's right side. The first form was an uninterrupted wall with no window. The second form was a brick wall with a closed window looking onto a spring-time forest environment (commensurate with the initial season of the study), and the third form was the same as the second but with the window open (Fig. 3).

Fig. 3.

The three window conditions: (A) an uninterpreted brick wall, (B) a closed window looking onto nature, and (C) an open window looking onto nature.

Nonvisual stimuli and cognitive task

All three conditions included anthropogenic elements recorded in the café, such as people's conversation noises at a moderate volume level (dB M = 48, range = 46–50). In the open window condition, birdsongs were also played in the background (dB levels did not change). Olfactory emissions consisted of brewing coffee, which was diffused in all three conditions (because a Starbucks was present in the union café), and the aroma of wet dirt, which was diffused only in the open window condition. Although past smellscape research has largely chosen compounds emitted by conifers or fragrant garden plants (Antonelli et al., 2020; Franco, Shanahan, & Fuller, 2017; Hedblom et al., 2019a; Song, Ikei, & Miyazaki, 2019), the landscape native to the study region and forest setting shown excluded these possible emission sources. Therefore, dirt was chosen as the most likely smell to be associated with the open window treatment.

Like other studies on restorative environments, we administered a cognitive task before VR exposure (Ohly et al., 2016). This allowed us to prefatigue the attentional capacities of participants as well as compare the restorative needs between groups and ensure they were approximately equal. The DSF presents participants with a randomized sequence of digits and has them reiterate the digits in the presented order, with each successful round increasing the sequence length of digits presented (Lezak, Howieson, Loring, & Fischer, 2004). We used the Psychology Experiment Building Language software 2.0 (Mueller & Piper, 2014) to administer a digital version of the DSF using a laptop provided to participants. The DSF provides a score from 0 to 10 with higher scores representing greater memory recall.

Measures

The survey was administered on a tablet after VR exposure. We used two complementary measures of psychological restorativeness/restoration as the dependent variables. A shortened form of the Perceived Restorativeness Scale (PRS; Cronbach's α = 0.84) was administered on an 11-point scale ranging from 0 (not at all) to 10 (completely) to measure how restorative an environment was to each respondent (Pasini, Berto, Brondino, Hall, & Ortner, 2014). The PRS included 11 items constituting four subscales (fascination, coherence, scope, and being away). These were measured by items such as “In places like this it is hard to be bored” (fascination), “Places like that are a refuge from nuisances” (being away), “In places like this it is easy to see how things are organized” (coherence), and “That place is large enough to allow exploration in many directions” (scope). The 6-item Restorative Outcome Scale (ROS; α = 0.85; Korpela, Ylén, Tyrväinen, & Silvennoinen, 2008) was administered on a 5-point agree–disagree scale as a measure of perceived restoration. Example items include “I feel calmer after being here” and “I can forget everyday worries here.” Although the PRS is based on ART and is commonly used in therapeutic environments research, the ROS has a broader theoretical basis drawing on both ART and SRT (Han, 2018; Pasanen, Ojala, Tyrväinen, & Korpela, 2018).

Analysis

Initial relationships between variables of interest were compared with Pearson correlation coefficients. Then, a series of one-way between-subjects analysis of variance (ANOVA) models were used to test for differences between conditions with respect to age, gender, race, semester, and pre-exposure DSF results to ensure similarity between groups.

To test our two hypotheses, ANOVA models checked for differences in restorativeness/restoration outcomes between conditions. When an overall mean difference was detected in an omnibus F-test, post hoc comparisons were examined using Fisher's Least Significant Difference (LSD) method. Homogeneity of variances between conditions was met for all outcome variables (p > 0.10).

Previous research on the restorativeness of natural versus built environments (Menardo et al., 2021; Schutte, Bhullar, Stilinović, & Richardson, 2017) and an a priori power analysis in G*Power (Faul, Erdfelder, Lang, & Buchner, 2007) suggested we would have sufficient statistical power with our sample size to conduct these one-way ANOVA models (N = 88, α = 0.05, F = 0.4, power = 0.92). Effect sizes were calculated with eta-squared (η²) calculation; 0.01, 0.06, and ≥0.14 represented small, medium, and large effects, respectively (Cohen, 1992). All statistical analyses were performed in R version 4.1.2 (R Core Team, 2021).

Results

Table 1 describes the participant characteristics. Most of the sample was female and non-Hispanic with White and Asian being the most common races represented. Ages ranged from 18 to 24 years (M = 20.0, SD = 1.3). ANOVAs revealed no differences across conditions in terms of demographics, semester of participation, or pre-exposure cognitive task (Table 1).

Table 1.

Participant Characteristics for Entire Sample and Across Experimental Conditions

	ENTIRE SAMPLE	NO WINDOW	CLOSED WINDOW	OPEN WINDOW	P
N	88	34	27	27	P
Age, n (%)					0.406
18	9 (10.2)	4 (11.8)	0 (0)	5 (18.5)
19	25 (28.4)	8 (23.5)	9 (33.3)	8 (29.6)
20	22 (25.0)	10 (29.4)	6 (22.2)	6 (22.2)
21	21 (23.9)	8 (23.5)	8 (29.6)	5 (18.5)
22	8 (9.1)	3 (8.8)	3 (11.1)	2 (7.4)
23	2 (2.3)	1 (2.9)	1 (3.7)	0 (0)
24	1 (1.1)	0 (0)	0 (0)	1 (3.7)
Female, n (%)	54 (61.4)	21 (61.8)	14 (51.9)	19 (70.4)	0.339
Ethnicity, n (%)					0.508
Hispanic	9 (10.2)	2 (5.9)	4 (14.8)	3 (11.1)
Non-Hispanic	79 (89.8)	32 (94.1)	23 (85.2)	24 (88.9)
Race, n (%)
American Indian	1 (1.1)	0 (0)	0 (0)	1 (3.7)	—
Asian	35 (39.8)	14 (41.2)	13 (48.1)	8 (29.6)	0.374
Black	5 (5.7)	4 (11.8)	1 (3.7)	0 (0)	—
White	39 (44.3)	15 (44.1)	8 (29.6)	16 (59.3)	0.091
Multiracial	8 (9.1)	1 (2.9)	5 (18.05)	2 (7.4)	0.164
Semester, n (%)					0.541
Spring	50 (56.8)	20 (58.8)	17 (63.0)	13 (48.1)
Fall	38 (43.2)	14 (41.2)	10 (37.0)	14 (51.9)
Pre-exposure cognitive task					0.094
DSF, M (SD)^†	7.79 (1.67)	7.9 (1.5)	8.3 (1.7)	7.2 (1.7)

p-Values associated with Welch's ANOVAs.

†

Results only available for reduced sample size due to data storage errors on laptop used to administer DSF (entire sample N = 78, no window N = 31, closed window N = 22, open window N = 25).

ANOVAs, analysis of variances; DSF, digit span forward; M, mean; SD, standard deviation.

Table 2 shows the bivariate correlations between the restorativeness/restoration outcomes. The ROS, PRS, and its subscales were positively correlated with each other without exception. These correlations were statistically significant except for the association between the coherence and fascination subscales.

Table 2.

Correlations Between Restorativeness/Restoration Outcome Measures

	PRS	SCOPE	FASCINATION	COHERENCE	BEING AWAY	ROS
PRS	—
scope	0.72 (<0.001)	—
Fascination	0.72 (<0.001)	0.53 (<0.001)	—
Coherence	0.66 (<0.001)	0.26 (<0.001)	0.12 (0.256)	—
Being away	0.80 (<0.001)	0.47 (<0.001)	0.48 (<0.001)	0.38 (<0.001)	—
ROS	0.66 (<0.001)	0.43 (<0.001)	0.50 (<0.001)	0.29 (<0.001)	0.70 (<0.001)	—

Notes: Pearson's correlation coefficient and p-values shown; significant correlations in bold, p < 0.05.

PRS, Perceived Restorativeness Scale; ROS, Restorative Outcome Scale.

Table 3 presents mean comparisons in restorativeness/restoration outcomes between experimental conditions. ANOVAs demonstrated large effect-sized differences by condition for the ROS and medium effect-sized differences by condition for the PRS, being away subscale, and fascination subscales. The coherence and scope subscales showed nonsignificant differences between conditions and were not investigated further.

Table 3.

Restorativeness/Restoration Outcomes Across Experimental Conditions

	BY CONDITION, M (SD)			BETWEEN CONDITION
	NO WINDOW	CLOSED WINDOW	OPEN WINDOW	DF	F	P	η²
N	34	27	27
ROS	2.21 (0.69)	2.68 (0.79)	3.01 (1.09)	85	6.71	0.002	0.136
PRS
Summary scale	3.25 (1.55)	3.98 (1.61)	4.39 (1.61)	85	4.09	0.020	0.088
Being away subscale	1.24 (1.56)	3.44 (2.94)	3.78 (3.03)	85	6.54	0.002	0.133
Coherence subscale	4.84 (2.67)	4.68 (2.21)	4.95 (2.64)	85	0.079	0.924	0.002
Fascination subscale	3.15 (2.08)	3.86 (2.16)	4.99 (2.05)	85	5.82	0.004	0.120
Scope subscale	3.38 (2.02)	4.24 (2.41)	4.35 (2.32)	85	1.76	0.178	0.040

Note: Results of one-way ANOVAs; significant omnibus F-tests shown in bold, p < 0.05.

LSD post hoc comparisons provided little evidence for the open window presenting greater restorative effects than the closed window (H1, Fig. 4). Mean values for the open window were consistently higher than mean values for the closed window (Table 3), but only the comparisons involving the fascination subscale trended toward significance.

Fig. 4.

Post hoc comparisons between experimental conditions and restorativeness/restoration outcomes. Notes: Means and standard errors with results of LSD tests shown, nonsignificant relationships in gray, ^†p < 0.10, *p < 0.05, **p < 0.01, ***p < 0.001. PRS, Perceived Restorativeness Scale; ROS, Restorative Outcome Scale.

In contrast, LSD post hoc comparisons provided considerable evidence that the open and closed window presented greater restorative effects than no window (H2, Fig. 4). The open window had significantly higher scores for four measures of restorative effects (ROS, PRS, fascination subscale, and being away subscale) than no window. The closed window had significantly higher scores for two measures of restorative effects (ROS and being away subscale) than no window. The closed window also showed higher scores for the PRS than no window, and this difference approached statistical significance.

Discussion

We conducted a study of the restorativeness/restoration outcomes of a window looking onto nature in a busy environment. This is the first study to examine the restorative qualities of opening a window looking onto nature in comparison with closed or no window settings, and the first study to examine the restorative qualities of windows looking onto nature in a busy setting to the best of our knowledge. We had two hypotheses: open and closed windows looking onto nature would have greater restorative effects than the absence of a window (H1); and an open window with visual, auditory, and olfactory exposure to nature would have greater restorative effects than a closed window with only visual nature exposure (H2).

We found several pieces of evidence in support of our first hypothesis. Both an open and closed window looking onto nature showed greater restorative qualities than the absence of a window with relatively few exceptions. Four of the six measures that we tested were higher in the open window condition than in the no window condition, including both the ROS and PRS. However, only two of the six measures were higher in the closed window condition than in the no window condition. In this case, the open window appeared to have the potential to facilitate attentional focus on interesting and pleasing aspects of the visual, auditory, and/or olfactory elements of nature.

This is in line with earlier findings that audio-visual congruence in natural settings enhances the sense of tranquility and satisfaction with the environment (Liu, Kang, Luo, & Behm, 2013; Pheasant, Horoshenkov, Watts, & Barrett, 2008). That is, the perception of landscape views is complemented by the available audio information. A recent study found 24% of overall satisfaction was explained by sound perceptions (Jeon & Jo, 2020). Not only can nature views benefit from the introduction of congruent sounds, but greenery views may also improve the perceived acoustic quality of environments by buffering negative responses to unwanted sounds (Renterghem, 2019).

We found very little support for our second hypothesis. An open window with the sights, sounds, and smells of nature did not show significantly greater restorative qualities than a closed window. Mean values for the ROS, PRS, and all four subscales of the PRS were larger for the open window than for the closed window condition, but post hoc comparisons found these mean differences were not statistically significant. However, the post hoc comparisons for the fascination subscale approached significance. This finding suggests that the open window—with its greater perceived visual access to nature as well as natural smells and sounds—might have been more captivating than the closed window for some participants but the effects were quite small.

Interestingly, neither an open nor a closed window modified the scope (i.e., breadth and exploration potential) or coherence (i.e., clear organization of objects) of the busy setting where our study took place (a university student café). This finding might be explained by the visual navigability being essentially the same between conditions in our study, which took place in a laboratory using a VR environment. Here, the window view was on the visual periphery of this virtual environment. These results reinforce ART and SRT's tenets that sensory-rich experiences in nature can have restorative effects that vary by the subdimensions of attention restoration, perceived restoration including stress reduction, and types of nature exposure (Kaplan, 1995; Ulrich, 1983).

Study implications

We acknowledge that previous research comparing actual and simulated nature views has reported that actual views are more restorative than their simulated counterparts (Frost et al., 2022; Kahn et al., 2008; Kjellgren & Buhrkall, 2010). Notably, Kahn et al. (2008) found that heart rate recovery from low-level stress was faster when participants had a glass window in the room than when they had a plasma display “window” of the same visual content visible through the glass window. However, both virtual windows and existing windows might have health and work performance benefits (Han, 2020; Lottrup, Stigsdotter, Meilby, & Claudi, 2015; Pati, Harvey, & Barach, 2008). The findings from this study reaffirm the potential value of virtual nature views as a supportive component for attention restoration.

Indoor spaces lacking direct views of the outdoors could benefit from virtual nature access points. Many built environments, including university facilities, have limited access to nature views due to surrounding buildings, pollutants, and allergens (Rivas et al., 2019; Tong, Chen, Malkawi, Adamkiewicz, & Spengler, 2016). The COVID-19 pandemic has also shifted university learning environments from in person to online, augmenting the psychological impacts of indoor and screen time on students' mental health (Browning et al., 2021). Our findings from a university setting suggest that virtual windows might help students cope with stress that may arise from returning to crowded environments and busyness in a postpandemic era.

This study contributes to the methodological and theoretical development of research on the restorative effects of virtual nature on mental health and cognitive performance. Our use of a CAVE-type VR environment is rarely employed in nature and health literature (Browning, Saeidi-Rizi, McAnirlin, Yoon, & Pei, 2020b). This technology has some benefits over other simulation forms (i.e., televisions, computer monitors, and head-mounted displays [HMDs]). On the one hand, it allows immersive content to be shown to participants and enables them to interact with their physical and virtual settings without wearing a virtual or augmented headset, which can be uncomfortable. CAVE environments also confer great experimental control and some ecological validity (Cruz-Neira et al., 1992). On the other hand, they may not confer immersive and, therefore, restorative content as 360° videos or computer-generated setting shown in HMDs (Annerstedt et al., 2013; Browning et al., 2020c; Joseph, Browning, & Jiang, 2020; Yeo et al., 2020). Future work should replicate this study using these technologies in virtual worlds or project open and closed windows of greenspace into actual busy settings using augmented reality.

Last, the study illuminates the need for theoretical improvements in nature's therapeutic benefits by examining additional busy settings. Places such as emergency rooms and waiting rooms in health care facilities, in addition to the university café studied here, might alter the way nature exposure benefits psychological well-being by activating only some aspects of restorative experiences.

Study limitations

This study was a preliminary investigation using a convenience sample of university students in a busy setting. We are mindful that in real life, many users may deliberately visit a familiar café seeking social interaction, in which case such an experience may provide attention restoration rather than induce the need for restoration (cf. Bellini, Hartig, & Bonaiuto, 2019). A next step to inform restorative design would be to employ a more generalizable sample as well as settings that are relevant to public use and more consistently associated with negative connotation, like hospital waiting rooms.

A second limitation relates to our use of a commonly accepted nature scene: green vegetation. Such a view might not be always restorative and comforting (Skår, 2010). Diversifying the types of nature shown would allow more generalizable comparisons between the restorative potentials of open and closed windows in ecoregions where lush green vegetation is not as common or familiar (i.e., arid environments, polar environments; Yin et al., 2022).

A third limitation relates to our outcome measures. Future studies on open versus closed windows looking onto nature might record attention restoration more objectively using cognitive tasks before and after exposure. Examining changes in task performance scores has been a common practice in research gauging the degree of restorative benefits, but our results were limited to participant's perceptions (cf. Berman, Jonides, & Kaplan, 2008; Bratman, Daily, Levy, & Gross, 2015; Hartig, 2011).

Another limitation is our introduction of human and nature sounds to create a more realistic experience. We did not manipulate the specific acoustic characteristics of these auditory stimuli (e.g., spectral content and temporal structure). Therefore, any potential masking between competing sounds remained unaccounted for (Kang et al., 2016).

We also did not configure the daylight effects of the window in the busy setting. Daylighting influences the restorative quality of windows (Chamilothori, Wienold, & Andersen, 2019) and is a significant factor in natural elements' therapeutic potential (Chi, Gutberg, & Berta, 2020). A broader range of weather and daylight conditions should be tested to improve the ecological validity of comparing the effects of an open or closed window using a VR environment.

Finally, we did not direct user's attention toward the window nor measured eye fixations in that direction. Our intent was to examine whether the availability of—not just the visual attention to—a multisensory nature exposure had restorative effects beyond a singular (visual) exposure or no exposure at all. We believed that this goal aligns well with the real-world design implications of a window being opened in a busy café, since students would not normally be told to pay attention to a specific window during their visit. In fact, several other experiments of windows looking onto nature have not directed user's attention, tracked eye movements, or captured visual attention with self-reported data (i.e., Benfield et al., 2015; Li & Sullivan, 2016; though see also Kahn et al., 2008; Ulrich, 1984). Still, future research should incorporate the measurement of visual attention to understand how the restorative effects of nature are attributable to microvisual exposures, longer durations of visual attention, and other nondirectional sensory inputs (sound and smell).

Conclusion

We found that a virtual window looking onto nature promoted some aspects of psychological restoration in a busy setting. Opening this virtual window so that it included the sounds and smells of nature was not clearly more restorative than keeping the virtual window closed. Applications of virtual windows with nature views in busy common spaces may improve the psychological well-being and cognitive performance of people in modern society who must handle multiple stimuli and stressors.

Footnotes

Authors' Contributions

M.B. corresponding author; developed the main idea for the study; collected part of the data; analyzed, interpreted, and presented the data; and assisted with writing the initial draft of the article. S.S. collected the rest of the data and wrote the first draft as well as revised the final article. A.D. reviewed and revised the article critically for important intellectual content and advised on the data analysis, interpretation, and presentation.

Author Disclosure Statement

The authors declare that there is no conflict of interest.

Funding Information

The authors received no financial support for the research, authorship, and/or publication of this study.

References

Annerstedt

, Jönsson

, Wallergård

, Johansson

, Karlson

, Grahn

, Hansen, Å. M., & Währborg

(2013). Inducing physiological stress recovery with sounds of nature in a virtual reality forest—Results from a pilot study. Physiology & Behavior, 118, 240–250.

Antonelli

, Donelli

, Barbieri

, Valussi

, Maggini

, & Firenzuoli

(2020). Forest volatile organic compounds and their effects on human health: A state-of-the-art review. International Journal of Environmental Research and Public Health, 17, 6506.

Bellini

, Hartig

, & Bonaiuto

(2019). Social support in the company canteen: A restorative resource buffering the relationship between job demands and fatigue. Work, 63, 375–387.

Benfield

J. A.

, Rainbolt

G. N.

, Bell

P. A.

, & Donovan

G. H.

(2015). Classrooms with nature views: Evidence of differing student perceptions and behaviors. Environment and Behavior, 47, 140–157.

Berman

M. G.

, Jonides

, & Kaplan

(2008). The cognitive benefits of interacting with nature. Psychological Science, 19, 1207–1212.

Berto

(2014). The role of nature in coping with psycho-physiological stress: A literature review on restorativeness. Behavioral Sciences, 4, 394–409.

Bowler

D. E.

, Buyung-Ali

L. M.

, Knight

T. M.

, & Pullin

A. S.

(2010). A systematic review of evidence for the added benefits to health of exposure to natural environments. BMC Public Health, 10, 456.

Bratman

G. N.

, Daily

G. C.

, Levy

B. J.

, & Gross

J. J.

(2015). The benefits of nature experience: Improved affect and cognition. Landscape and Urban Planning, 138, 41–50.

Browning

M. H. E

. M., Larson

L. R.

, Sharaievska

, Rigolon

, McAnirlin

, Mullenbach

, Cloutier

, Vu

T. M.

, Thomsen

, Reigner

, Metcalf

E. C.

, D'Antonio

, Helbich

, Bratman

G. N.

, & Alvarez

H. O.

(2021). Psychological impacts from COVID-19 among university students: Risk factors across seven states in the United States. PLoS One, 16, e0245327.

10.

Browning

M. H. E

. M., Mimnaugh

K. J.

, van Riper

C. J.

, Laurent

H. K.

, LaValle

S. M.

, Mimnaugh

K. J.

, & Browning

M. H. E

. M. (2020a). Can simulated nature support health? Comparing short, single-doses of 360-degree nature videos in virtual reality with the outdoors. Frontiers in Psychology, 10, 2667.

11.

Browning

M. H. E

. M., Saeidi-Rizi

, McAnirlin

, Yoon

, & Pei

(2020b). The role of methodological choices in the effects of experimental exposure to simulated natural landscapes on human health and cognitive performance: A systematic review. Environment and Behavior, 53, 687–731.

12.

Browning

M. H. E

. M., Suppakittpaisarn

, Shan

, Joseph

, Weng

, & Yuan

(2020c). Human health assessments of green infrastructure designs using virtual reality no title. Landscape Architecture, 27, 35–49.

13.

Browning

, & Lee

(2017). Within what distance does “greenness” best predict physical health? A systematic review of articles with GIS buffer analyses across the lifespan. International Journal of Environmental Research and Public Health, 14, 675.

14.

Chamilothori

, Wienold

, & Andersen

(2019). Adequacy of immersive virtual reality for the perception of daylit spaces: Comparison of real and virtual environments. Leukos, 15, 203–226.

15.

Chang

C. C.

, Oh

R. R. Y.

, Le Nghiem

T. P.

, Zhang

, Tan

C. L.

, Lin

B. B.

, …, & Carrasco

L. R.

(2020). Life satisfaction linked to the diversity of nature experiences and nature views from the window. Landscape and Urban Planning, 202, 103874.

16.

Chang

C.- Y.

, & Chen

P.- K.

(2005). Human response to window views and indoor plants in the workplace. HortScience, 40, 1354–1359.

17.

Chi

, Gutberg

, & Berta

(2020). The conceptualization of the natural environment in healthcare facilities: A scoping review. HERD: Health Environments Research & Design Journal, 13, 30–47.

18.

Chirico

, & Gaggioli

(2019). When virtual feels real: Comparing emotional responses and presence in virtual and natural environments. Cyberpsychology, Behavior, and Social Networking, 22, 220–226.

19.

Coensel

B. D.

, Vanwetswinkel

, & Botteldooren

(2011). Effects of natural sounds on the perception of road traffic noise. The Journal of the Acoustical Society of America, 129, EL148–EL153.

20.

Cohen

(1992). A power primer. Psychological Bulletin, 112, 155–159.

21.

Cox

D. T. C.

, Shanahan

D. F.

, Hudson

H. L.

, Fuller

R. A.

, & Gaston

K. J.

(2018). The impact of urbanisation on nature dose and the implications for human health. Landscape and Urban Planning, 179, 72–80.

22.

Cruz-Neira

, Sandin

D. J.

, DeFanti

T. A.

, Kenyon

R. V

, & Hart

J. C.

(1992). The CAVE: Audio visual experience automatic virtual environment. Communications of the ACM, 35, 64–73.

23.

Devlin

A. S.

(2018). Concepts, theories, and research approaches. In A. S. B. T. Devlin (ed.), Environmental Psychology and Human Well-Being (pp. 1–28). London: Elsevier Inc.

24.

Dzhambov

, & Dimitrova

(2017). Occupational noise exposure and the risk for work-related injury: A systematic review and meta-analysis. Annals of Work Exposures and Health, 61, 1037–1053.

25.

Dzhambov

A. M.

, Lercher

, Stoyanov

, Petrova

, Novakov

, & Dimitrova

D. D.

(2021). University students' self-rated health in relation to perceived acoustic environment during the covid-19 home quarantine. International Journal of Environmental Research and Public Health, 18, 1–21.

26.

Faul

, Erdfelder

, Lang

A.-G.

, & Buchner

(2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods, 39, 175–191.

27.

Felsten

(2009). Where to take a study break on the college campus: An attention restoration theory perspective. Journal of Environmental Psychology, 29, 160–167.

28.

Franco

L. S.

, Shanahan

D. F.

, & Fuller

R. A.

(2017). A review of the benefits of nature experiences: More than meets the eye. International Journal of Environmental Research and Public Health, 14, 864.

29.

Frost

, Kannis-Dymand

, Schaffer

, Millea

, Allen

, Stallman

, Mason

, Wood

, & Atkinson-Nolte

(2022). Virtual immersion in nature and psychological well-being: A systematic literature review. Journal of Environmental Psychology, 80, 101765.

30.

Grassini

, Revonsuo

, Castellotti

, Petrizzo

, Benedetti

, & Koivisto

(2019). Processing of natural scenery is associated with lower attentional and cognitive load compared with urban ones. Journal of Environmental Psychology, 62, 1–11.

31.

Han

K. T.

(2018). A review of self-report scales on restoration and/or restorativeness in the natural environment. Journal of Leisure Research, 49, 151–176.

32.

Han

K.- T.

(2020). Validity of self-reported Well-being Measures and Restoration Scale for emotions, attention, and physiology. Journal of Leisure Research, 52, 154–179.

33.

Hao

, Kang

, & Wörtche

(2016). Assessment of the masking effects of birdsong on the road traffic noise environment. The journal of the Acoustical Society of America, 140, 978–987.

34.

Hartig

(2011). Issues in restorative environments research: Matters of measurement. Psicología Ambiental, 2011, 41–66.

35.

Hartig

, & Jahncke

(2017). Letter to the editor: Attention restoration in natural environments: Mixed mythical metaphors for meta-analysis. Journal of Toxicology and Environmental Health, Part B, 20, 305–315.

36.

Hartig

, Mitchell

, De Vries

, & Frumkin

(2014). Nature and health. Annual Review of Public Health, 35, 207–228.

37.

Hedblom

, Gunnarsson

, Iravani

, Knez

, Schaefer

, Thorsson

, & Lundström

J. N.

(2019a). Reduction of physiological stress by urban green space in a multisensory virtual experiment. Scientific Reports, 9, 10113.

38.

Hedblom

, Gunnarsson

, Schaefer

, Knez

, Thorsson

, & Lundström

J. N.

(2019b). Sounds of nature in the city: No evidence of bird song improving stress recovery. International Journal of Environmental Research and Public Health, 16, 1390.

39.

Jahncke

(2012). Open-plan office noise: The susceptibility and suitability of different cognitive tasks for work in the presence of irrelevant speech. Noise and Health, 14, 315–320.

40.

Jahncke

, Hygge

, Halin

, Green

A. M.

, & Dimberg

(2011). Open-plan office noise: Cognitive performance and restoration. Journal of Environmental Psychology, 31, 373–382.

41.

Jeon

J. Y.

, & Jo

H. I.

(2020). Effects of audio-visual interactions on soundscape and landscape perception and their influence on satisfaction with the urban environment. Building and Environment, 169, 106544.

42.

, Song

, & Miyazaki

(2019). Physiological benefits of viewing nature: A systematic review of indoor experiments. International Journal of Environmental Research and Public Health, 16, 4739.

43.

Joseph

, Browning

M. H. E

. M. E. M., & Jiang

(2020). Using immersive virtual environments (IVEs) to conduct environmental design research: A primer and decision framework. HERD: Health Environments Research & Design Journal, 13, 11–25.

44.

Kahn

P. H.

, Friedman

, Gill

, Hagman

, Severson

R. L.

, Freier

N. G.

, Feldman

E. N.

, Carrère

, & Stolyar

(2008). A plasma display window?—The shifting baseline problem in a technologically mediated natural world. Journal of Environmental Psychology, 28, 192–199.

45.

Kang

, Aletta

, Gjestland

T. T.

, Brown

L. A.

, Botteldooren

, Schulte-Fortkamp

, …, & Lavia

(2016). Ten questions on the soundscapes of the built environment. Building and Environment, 108, 284–294.

46.

Kaplan

(2001). The nature of the view from home: Psychological benefits. Environment and Behavior, 33, 507–542.

47.

Kaplan

, & Kaplan

(1989). The experience of nature: A psychological perspective. New York: Cambridge University Press Archive.

48.

Kaplan

(1995). The restorative benefits of nature: Toward an integrative framework. Journal of Environmental Psychology, 15, 169–182.

49.

Kaplan

, & Berman

M. G.

(2010). Directed attention as a common resource for executive functioning and Self-Regulation. Perspectives on Psychological Science, 5, 43–57.

50.

Kardan

, Gozdyra

, Misic

, Moola

, Palmer

L. J.

, Paus

, & Berman

M. G.

(2015). Neighborhood greenspace and health in a large urban center. Scientific Reports, 5, 11610.

51.

Kellert

S. R.

(2003). Kinship to mastery: Biophilia in human evolution and development. Washington, DC: Island Press.

52.

Kellert

S. R.

, Wilson

E. O.

, McVay

, Katcher

, McCarthy

, Wilkins

, Ulrich

, Shepard

, Antoine

S. S.

, & Diamond

(1993). The Biophilia Hypothesis. Washington, DC: Island Press.

53.

Kim

, Cha

S. H.

, Koo

, & Tang

(2018). The effects of indoor plants and artificial windows in an underground environment. Building and Environment, 138, 53–62.

54.

Kjellgren

, & Buhrkall

(2010). A comparison of the restorative effect of a natural environment with that of a simulated natural environment. Journal of Environmental Psychology, 30, 464–472.

55.

Korpela

K. M.

, Ylén

, Tyrväinen

, & Silvennoinen

(2008). Determinants of restorative experiences in everyday favorite places. Health & Place, 14, 636–652.

56.

Korpela

, Nummi

, Lipiäinen

, De Bloom

, Sianoja

, Pasanen

, & Kinnunen

(2017). Nature exposure predicts well-being trajectory groups among employees across two years. Journal of Environmental Psychology, 52, 81–91.

57.

Lassonde

K. A.

, Gloth

C. A.

, & Borchert

(2012). Windowless classrooms or a virtual window world: Does a creative classroom environment help or hinder attention?. Teaching of Psychology, 39, 262–267.

58.

Lezak

M. D.

, Howieson

D. B.

, Loring

D. W.

, & Fischer

J. S

. (2004). Neuropsychological assessment. USA: Oxford University Press.

59.

, & Sullivan

W. C.

(2016). Impact of views to school landscapes on recovery from stress and mental fatigue. Landscape and Urban Planning, 148, 149–158.

60.

Liu

, Kang

, Luo

. & Behm

(2013). Landscape effects on soundscape experience in city parks. Science of the Total Environment, 454, 474–481.

61.

Lottrup

, Stigsdotter

U. K.

, Meilby

, & Claudi

A. G.

(2015). The workplace window view: A determinant of office workers' work ability and job satisfaction. Landscape Research, 40, 57–75.

62.

Marselle

M. R.

, Irvine

K. N.

, Lorenzo-Arribas

, & Warber

S. L.

(2016). Does perceived restorativeness mediate the effects of perceived biodiversity and perceived naturalness on emotional well-being following group walks in nature?. Journal of Environmental Psychology, 46, 217–232.

63.

Masoudinejad

, & Hartig

(2020). Window view to the sky as a restorative resource for residents in densely populated cities. Environment and Behavior, 52, 401–436.

64.

Menardo

, Brondino

, Hall

, & Pasini

(2021). Restorativeness in natural and urban environments: A meta-analysis. Psychological Reports, 124, 417–437.

65.

Mueller

S. T.

, & Piper

B. J.

(2014). The psychology experiment building language (PEBL) and PEBL test battery. Journal of Neuroscience Methods, 222, 250–259.

66.

Ohly

, White

M. P.

, Wheeler

B. W.

, Bethel

, Ukoumunne

O. C.

, Nikolaou

, & Garside

(2016). Attention restoration theory: A systematic review of the attention restoration potential of exposure to natural environments. Journal of Toxicology and Environmental Health – Part B: Critical Reviews, 19, 305–343.

67.

Olszewska-Guizzo

, Escoffier

, Chan

, & Yok

T. P.

(2018). Window view and the brain: Effects of floor level and green cover on the alpha and beta rhythms in a passive exposure EEG experiment. International Journal of Environmental Research and Public Health, 15, 2358.

68.

Palanica

, Lyons

, Cooper

, Lee

, & Fossat

(2019). A comparison of nature and urban environments on creative thinking across different levels of reality. Journal of Environmental Psychology, 63, 44–51.

69.

Pálsdóttir

A. M.

, Spendrup

, Mårtensson

, & Wendin

(2021). Garden smellscape–experiences of plant scents in a nature-based intervention. Frontiers in Psychology, 12, 667957.

70.

Pasanen

T. P.

, Ojala

, Tyrväinen

, & Korpela

K. M.

(2018). Restoration, well-being, and everyday physical activity in indoor, built outdoor and natural outdoor settings. Journal of Environmental Psychology, 59, 85–93.

71.

Pasini

, Berto

, Brondino

, Hall

, & Ortner

(2014). How to measure the restorative quality of environments: The PRS-11. Procedia – Social and Behavioral Sciences, 159, 293–297.

72.

Pati

, Harvey Jr

T. E.

, & Barach

(2008). Relationships between exterior views and nurse stress: An exploratory examination. HERD: Health Environments Research & Design Journal, 1, 27–38.

73.

Pheasant

, Horoshenkov

, Watts

, & Barrett

(2008). The acoustic and visual factors influencing the construction of tranquil space in urban and rural environments tranquil spaces-quiet places?. The Journal of the Acoustical Society of America, 123, 1446–1457.

74.

Press

, & Minta

S. C.

(2000). The smell of nature: Olfaction, knowledge and the environment. Ethics, Place and Environment, 3, 173–186.

75.

R Core Team (2021). R: A language and environment for statistical computing. https://www.R-project.org

76.

Ratcliffe

(2021). Sound and soundscape in restorative natural environments: A narrative literature review. Frontiers in Psychology, 12, 570563.

77.

Ratcliffe

, Gatersleben

, & Sowden

P. T.

(2013). Bird sounds and their contributions to perceived attention restoration and stress recovery. Journal of Environmental Psychology, 36, 221–228.

78.

Renterghem

T. V.

(2019). Towards explaining the positive effect of vegetation on the perception of environmental noise. Urban Forestry & Urban Greening, 40, 133–144.

79.

Rivas

, Basagaña

, Cirach

, López-Vicente

, Suades-González

, Garcia-Esteban

, Álvarez-Pedrerol

, Dadvand

, & Sunyer

(2019). Association between early life exposure to air pollution and working memory and attention. Environmental Health Perspectives, 127, 57002.

80.

Schutte

N. S.

, Bhullar

, Stilinović

E. J.

, & Richardson

(2017). The impact of virtual environments on restorativeness and affect. Ecopsychology, 9, 1–7.

81.

Skår

(2010). Forest dear and forest fear: Dwellers' relationships to their neighbourhood forest. Landscape and Urban Planning, 98, 110–116.

82.

Song

, Ikei

. & Miyazaki

(2019). Physiological effects of forest-related visual, olfactory, and combined stimuli on humans: An additive combined effect. Urban Forestry & Urban Greening, 44, 126437.

83.

Tabrizian

, Baran

P. K.

, Smith

W. R.

, & Meentemeyer

R. K.

(2018). Exploring perceived restoration potential of urban green enclosure through immersive virtual environments. Journal of Environmental Psychology, 55, 99–109.

84.

Thompson

, Smith

R. B.

, Karim

Y. B.

, Shen

, Drummond

, Teng

, & Toledano

M. B.

(2022). Noise pollution and human cognition: An updated systematic review and meta-analysis of recent evidence. Environment International, 158, 106905.

85.

Tong

, Chen

, Malkawi

, Adamkiewicz

, & Spengler

J. D.

(2016). Quantifying the impact of traffic-related air pollution on the indoor air quality of a naturally ventilated building. Environment International, 89, 138–146.

86.

Ulrich

R. S.

(1983). Aesthetic and affective response to natural environment. In I. Altman, & J. F. Wohlwill (eds.), Behavior and the natural environment (pp. 85–125). Boston, MA: Springer.

87.

Ulrich

R. S.

(1984). View through a window may influence recovery. Science, 224, 420–421.

88.

Ulrich

R. S.

, Simons

R. F.

, Losito

B. D.

, Fiorito

, Miles

M. A.

, & Zelson

(1991). Stress recovery during exposure to natural and urban environments. Journal of Environmental Psychology, 11, 201–230.

89.

Valtchanov

, Barton

K. R.

, & Ellard

(2010). Restorative effects of virtual nature settings. Cyberpsychology, Behavior, and Social Networking, 13, 503–512.

90.

van Esch

, Minjock

, Colarelli

S. M.

, & Hirsch

(2019). Office window views: View features trump nature in predicting employee well-being. Journal of Environmental Psychology, 64, 56–64.

91.

Victorson

, Luberto

, & Koffler

(2020). Nature as medicine: Mind, body, and soil. The Journal of Alternative and Complementary Medicine, 26, 658–662.

92.

Wohn

D. Y.

, Kum-Biocca

H. H.

, Sharma

, & Khandakar

(2020). A room with a “fake” view: Installing digital windows in windowless offices. In ACM International Conference on Interactive Media Experiences (pp. 180–184). Cham: Springer.

93.

Xue

, Lau

S. S.

, Gou

, Song

, & Jiang

(2019). Incorporating biophilia into green building rating tools for promoting health and wellbeing. Environmental Impact Assessment Review, 76, 98–112.

94.

Yao

, Chen

, Wang

, & Zhang

(2021). Impact of exposure to natural and built environments on positive and negative affect: A systematic review and meta-analysis. Frontiers in Public Health, 9, 758457.

95.

Yeo

N. L.

, White

M. P.

, Alcock

, Garside

, Dean

S. G.

, Smalley

A. J.

, & Gatersleben

. (2020). What is the best way of delivering virtual nature for improving mood? An experimental comparison of high definition TV, 360° video, and computer generated virtual reality. Journal of Environmental Psychology, 72, 101500.

96.

Yin

, Bratman

G. N.

, Browning

M. H. E

. M., Spengler

J. D.

& Olvera-Alvarez

H. A.

(2022). Stress recovery from virtual exposure to a brown (desert) environment versus a green environment. Journal of Environmental Psychology, 81, 101775.

97.

Yin

, Zhu

, MacNaughton

, Allen

J. G.

, & Spengler

J. D.

(2018). Physiological and cognitive performance of exposure to biophilic indoor environment. Building and Environment, 132, 255–262.

98.

Zhang

, Yu

, Zhao

, Sun

, & Vejre

(2020). Links between green space and public health: A bibliometric review of global research trends and future prospects from 1901 to 2019. Environmental Research Letters, 15, 63001.