1. Introduction
University students spend most of their time studying on campus, which requires effort and may cause attention fatigue. Reports of universities and colleges worldwide indicate the outbreak of mental health problems among college students. According to data statistics from the United States in the autumn of 2018, approximately 12.5% of 26,181 college students at 40 universities felt tired, stressed out or sleepy during the previous 7 days [
1] and 29.5% of them had experienced overwhelming anxiety over the previous two weeks [
2]. In his book
The Stressed Years of Their Lives, Dr. Anthony Rostain stated that current college life may be more stressful than ever before [
3]. Therefore, to provide students with an effective approach to appropriately alleviate mental fatigue is a pressing concern.
To restore attention through the exposure to the environment is one effective approach [
4]. Frequent visits to green spaces by university students can improve their overall mood and reduce perceived stress [
5]. Therefore, a university campus must not only provide an environment for study but also one that promotes physical and mental health. However, the landscape types of universities are generally divided into core landscape areas, memorial spaces, square spaces and courtyard spaces [
6], which are designed to reflect the campus culture and project the image of the university [
7]. Therefore, designers must be attentive to the health requirements of the primary users of the campus and must incorporate a restorative environmental design into the campus design.
Recent studies have examined restorative environments for students primarily from two aspects, namely the naturalness of the physical environment and student activities, through comparing the vegetation space and bare ground or walls [
8,
9], preferred restorative activities [
10] and active or passive participation [
5]. Although the attention restoration theory (ART) proposes four factors by which to evaluate a restorative environment [
11], relevant studies have focused more on the psychological aspect and lack of the transformation in characteristics of the physical environmental aspect. In general, the environmental factors for attention restoration have been less studied and a design guide is not available to instruct how to create a space on a university campus.
The purpose of this study was to examine the primary perceptual factors associated with selecting the most relaxing landscape type on a university campus. To meet this aim, we addressed the following research questions: (1) What type of landscape has more perceived attention recovery effect? (2) Which perceptual factors have a significant effect on the choice of campus space? (3) Which factors should be considered before designing a restorative campus space? To answer the aforementioned questions, the concept of an “attention restoration space,” which can help people to relax and can relieve stress, restore attention and improve work and study efficiency, was proposed. To relate perceptual factors with environmental design elements, a questionnaire was designed to obtain information on landscape type preferences and spatial perceptual factors preferred by students. To explore the influence of landscape types and perceptual factors on the design of the attention restoration space, regression modeling with categorical regression (CATREG) analysis was employed. Therefore, each factor was ranked and suggestions for the optimal design were elicited. The results can enrich the ART, provide a practical reference for designers and provide an approach to improve the construction of university campuses.
4. Discussion
4.1. Optimal Selection of Landscape Types based on Environmental Preference
It would be effective to create an attention restoration space with more preferred spaces, given campus conditions. Water exhibited high desirability among the landscape elements for restoration [
43]. Water should be a prioritized landscape type when designing a space, although it could be limited by economic conditions, the geographical location of the campus, water resources and climate regions. In particular, large open water areas were more preferred on the campus map. The results from the campus mapping suggested that vegetation spaces with large open lawns surrounded with tall trees are highly preferred spaces. Academic courtyards can employ a healing garden concept in a compact campus [
44]. However, courtyards with open windows or square spaces without any shelter are the least preferred spaces. Students reported that they would enjoy squares if shade and seats are provided. Natural elements could be employed to improve such spaces. For example, the arrangement of deciduous trees in courtyards may provide privacy as well as reduce the direct contact of sight from indoor and outdoor.
Four types of spaces on campuses were reported to have restorative potential and the results indicated that environments with natural elements as more restorative than those with artificial elements [
45]. For campuses with enclosed spaces, the courtyard spaces may increase overall satisfaction. For campuses with a higher number of individual buildings, improving vegetation spaces in front of the buildings may yield a positive effect. Overall, the priority should be to enhance the spaces along the necessary activity paths of students and integrate the primary perception factors with the design.
4.2. Spatial Quality Improvement Based on Primary Perceptual Factors
The primary perceptual factors were treated as exploratory factors to contribute to ART in the research on restorative campus environments. Recognition was in accordance with legibility and sense of belonging was comparable to compatibility in ART [
20]. The findings of accessibility were consistent with the previous studies that spaces near nature have improved perceived restorative effects [
46,
47]. These findings indicate that students consider visibility and comfort to be crucial factors that contribute to restorativeness. Moreover, the study contributes to the ongoing debate on healthy planning by indicating that the quality of the environment and seats must be a priority. The primary perceptual factors are discussed in spatial dimensions in the following section to assist future research and design.
Table 5 shows an improved pattern of the five primary perceptual factors. The layout of the attention restoration space should be designed within an acceptable walking distance to encourage access and be located on a path where frequent activity happens [
48,
49]. Visibility should be enhanced through introducing good lines of sight from different perspectives, as well as a high green looking ratio [
50]. Sufficient landscape space should be reserved around the library and teaching buildings to ensure the continuity of green spaces, water bodies and visual openness for future campus planning. The facilities and the neatness of the environment should be improved to enhance the comfort factor [
51]; providing movable seats for students and avoiding cold materials or windward locations would be worthwhile. Lighting at night should be enhanced in the necessary activity spaces because night is the peak preferred usage time. A clear layout pattern with a coordinated and unified design can enhance recognition [
22], which may include making clear guidance to the accessible space using similar design approaches and improving spatial coherence through road planning. The demand of users for the sense of belonging could be achieved through designing a place they feel safe [
52,
53]. It is interesting to note that the need for places that allow a person to see but without being seen was consistent with the prospect-refuge theory developed by Appleton [
54]. For instance, setting up shelters to provide privacy could be beneficial.
4.3. Comprehensive Evaluation of Key Design Factors
In this study, the primary design factors of attention restoration spaces are landscape types and perceptual factors, which interact with each other. The evaluation of their advantages and disadvantages based on the actual situation of different campuses is crucial (
Table 6). Therefore, the design factors must be analyzed using the CATREG model.
Waterfront spaces are seldom affected by accessibility, visibility, comfort and sense of belonging. The higher the recognition is, the higher the restorative score of the waterfront space is. Accessibility is an inferior element for waterfront spaces (
Table 6) because most students reported that the distance between waterfront spaces and learning spaces was far. The other three perceptual factors could be considered to be second options in the specific design.
Vegetation spaces on campuses are usually the most common landscape types; however, the ones students perceived to be restorative must follow the primary perceptual factors. Sense of belonging suggests that the open green spaces can provide some shelters, which is in accordance with the campus mapping result of a large lawn with trees. Visibility is significant because of the preference for relaxation through taking in views through windows and the restorative effect is primarily a result of the green vision rate [
55]. Therefore, improving visibility near buildings and along the frequently visited routes is essential. The importance of recognition, accessibility and comfort are similar, as determined through the CATREG model and should be considered according to the campus situation.
The courtyard spaces have an enclosure layout, thus providing a sense of belonging, which could be a dominant factor. People could enjoy the view of the courtyard from the window and from the surrounding buildings, which indicates that effects on visibility could be weak. Moreover, reaching the courtyard can be easy for students. Therefore, recognition and comfort should be improved when considering the users around the courtyard.
Square spaces have a strong sense of form with a large open space of pavement and thus the recognition influence is weak. The other four primary perceptual factors can be improved. Among these factors, the sense of belonging has the strongest influence because of the lack of shelter.
The result of “importance” in the CATREG model provides an optimization scheme for the design of attention restoration spaces based on the student requirements for landscape types. The model suggested that all factors are crucial and only the remaining variables are most salient in decision making concerning spatial designs.
4.4. Limitations and Future Research
This study examined the attention restoration spaces based on the evidence of the environmental preference of students for using campus landscapes as a space to restore attention. However, this study has limitations, which can be further examined in future research. The sample campuses were in northeastern China and thus are affected by cold seasons. Therefore, the concerns and needs of university students may differ from those in other climate regions. Future research should examine seasonal factors. Moreover, similar studies in diverse regions with varied cultural backgrounds, education levels and climate conditions may provide further insights into specific contexts. Further studies can explore specific design elements and seasonal effects, focusing on campus landscapes. Another limitation is the sample size of each campus. Although all campuses were considered as a part of the complete sample to explore the difference between landscape types, the large workload limited the number of collected questionnaires. Future research may include more students using the aforementioned method at certain campuses.