Color Images in Architecture for Stress-Relief ^†

Abstract

The emotional responses and perceptual preferences of individuals for urban public spaces are shaped by their interactions with the physical environment. Emotions and perceptions are inextricably linked, forming the basis of people’s spatial experience. For instance, the presence of dense city buildings can result in feelings of crowding and friction. By improving the urban landscape, it is possible to reduce the stress experienced by citizens. In this study, architectural styles and building facade colors were examined to explore design approaches and features of stress-relieving building facades and identify metrics that measure participants’ stress-relief when viewing buildings. The color of 600 buildings in Japan and Taiwan was analyzed to understand stress-relief from architecture. Semi-structured interviews were conducted with 70 participants who viewed images of 30 buildings. The semantic differential method with a seven-point image scale was employed to assess the stress-relieving potential of different architectural styles and colors. The findings of this study indicated that participants perceived that architectural colors influenced feelings of relief. Additionally, they anticipated variations in architectural colors contingent on architectural usage patterns. To substantiate this observation, three principles—city image, identity, and spiritual atmosphere—were identified as fundamental elements in designing cities for livability. The three principles are illustrated by several case studies for a detailed understanding of their applicability in biodesign practices.

1. Introduction

City planners and society at large are increasingly aware of the value of urban stress-relief. Consequently, a variety of services have been transformed in the environmental space, including parks, entertainment, aesthetic, and spiritual experiences [1]. Consequently, it is necessary to determine the impact of the built environment on the physiology and behavior of those exposed to it. Those residing in urban areas frequently contact the built environment. The United Nations Sustainable Development Goals, established in 2015, include Goal 11 to “make cities and human settlements inclusive, safe, resilient, and sustainable,” and Goal 8 to “promote sustained, inclusive, and sustainable economic growth, full and productive employment, and decent work for all”. Consequently, the construction of a sustainable city necessitates the provision of a perpetually evolving visual landscape. The architectural and landscape design of urban areas plays a pivotal role in the achievement of these objectives. A city whose urban architecture features stress-relieving design elements is likely to have a unique, stress-relieving image.

This article presents the results of a research project investigating the potential of building color to relieve stress. The findings can allow for the planning and design of urban environments to become stress-relieving cities. The concept of quality of life encompasses a multitude of factors, including an individual’s physical health, mental state, degree of independence, social relationships, personal beliefs, and relationship to salient features in the environment. Previous studies [2] have mainly focused on the impact of building shape and the addition of green plants on human psychology and physiology. However, we defined the factors of urban stress as the psychophysiological stress of urban people, which exists in a complex matrix of environmental factors (including landscape, architecture, etc.), and socioeconomic and political conditions (such as urban building density). Numerous employment, housing, and workplace issues require attention. The appearance of buildings has always been a prominent feature in people’s lives. Nevertheless, there has been a paucity of research investigating the emotional impact of these structures.

According to Michael [3], the performance of buildings and landscapes in cities affects the mood of people and the city atmosphere, which is also the issue of happy cities being discussed in countries. Cells in the human brain’s hippocampus interact with the geometry, arrangement, and color of the urban architectural spaces. Therefore, urban architecture must conform to the designer’s style and characteristics and affect the visual and emotional state of residents to increase the sustainability of the city. The spirituality of a city includes the observable objects and the spiritual feelings. The spirituality of the city is divided into external performance and internal feeling (Figure 1). Previous research found [4] that shapes can be stored in memory through their emotional and cognitive impact on the viewer, and that buildings can facilitate the formation of memories and emotions of people. The study found that complex shapes are more attractive and influential than simple shapes or straight lines, but also require more mental processing and higher mental effort. This is because complex shapes contain visual information that needs to be processed and retained in memory. Compared with the color of the building, their effect is consistent.

2. Affective Atmosphere and Material Imagination of Stress-Relieving Architecture

2.1. Stress-Relieving

In addition to shape, urban color is a significant element when planning urban space [5]. The color of urban buildings is a component of the urban landscape, offering residents a distinctive visual experience and perception of the spatial environment. These factors influence residents’ emotions and behaviors [6,7]. Consequently, color can evoke and promote emotions, which is a concept that can be employed in urban architecture. The impact of vision is the most direct sensorily [8]. The perceptions and emotions of urban residents, including comfort, safety, vitality, and depression, are influenced by their visual exposure to the built environment [9,10,11,12,13]. When individuals are traversing a city street or pausing in a public square, they may not be aware of a specific color but experience an emotional response to the prevailing ambiance. We observed that expressions such as “this place makes me feel good” or “the surroundings are quite disturbing” can often substitute for the evaluations of the color combinations. Mahnke posited that patterns and color combinations in urban environments elicit both conscious and unconscious emotional responses. The combination of shaped lines and incongruous color schemes results in visual disturbances, disorientation, and stress or depression [14].

According to the “City Pulse Survey 2021” by Gensler, the largest construction company in the United States, many countries have begun to consider future cities that can resist infectious diseases by avoiding loneliness while maintaining personal space as expressed by “physical, not social, distancing.” These concepts are components of urban redesign [15]. The movement restrictions during the COVID-19 pandemic caused a rethinking of environmental space planning and design. Designers need to create open spaces that are comfortable and relaxing; enhance social interaction; and reduce antisociality, loneliness, and stress. Urban planning has transitioned to land planning in many countries.

We used the images of large buildings, which increase the pressure on cities. In such a dense city, if the architectural colors are full of changes, it brings a heavy sense of pressure to the citizens. Among buildings, the color of residential buildings is relatively simple as residents do not want overly vibrant colors that may affect their mood in living. A survey of the appearance of 600 buildings revealed that achromatic colors were used, so the residents of these two places tended to have a restrained and conservative disposition.

2.2. Research Framework

As Day [16] posited, the relationships between urban forms, spaces, and color invigorate the individual or sap them of their life force. Ellard [17] researched the impact of design on psychology, demonstrating that individuals were unaware of the ways in which their physical and psychological well-being were influenced by the environment. Ellard corroborated the physiological response with the collected experimental data and found that, regarding their stress levels, respondents perceived it to be a relatively minor issue. However, when physiological responses were measured, they revealed that stress levels were significantly elevated. The research results demonstrated that the psychological mood of citizens is unconsciously influenced by the shape and color of buildings in urban areas. The intricacy of alterations to the external facade of a building necessitates research on cognitive resources and emotional responses. Figure 2 illustrates the framework employed in this research, which shows that the appearance of buildings and the associated mood can interfere with message transmission and affect user perceptions.

3. Materials and Methods

3.1. Research Method

Exposure to a natural urban environment can lead to positive changes in mood and stress reduction, as well as a lower heart rate compared to the built environment. Thus, it is needed to ensure the building is able to relieve the pressure of the citizens. Based on the existing theory, we adopted experimental methods to investigate the stress-relieving building facade. We explored the theoretical background [18] to develop a model to test the hypotheses [19]. We collected a large number of photos of buildings in Japan and Taiwan, compared the use of color of the buildings, and then experimented to understand the subjective feelings of the buildings. We predicted the color of city buildings that affected the stress index of residents.

In our research, the method in Figure 3 was used to obtain the subjects’ views and feelings on the decompression structure. We used the same research method to examine the impact of building color on high-stress people. We added a building matrix to explore the impact of architectural styles in different regions. We analyzed the perceptions of stress-relief and pressure of 70 subjects to analyze the difference between previous and present thoughts and external stimuli. The subjects were asked for the decompression index of 30 buildings using the Decompression Building Scale (Figure 3).

3.2. Sample and Data

Seventy office workers in Taiwan with over five years of experience participated in the study. Each individual was employed on a full-time basis and worked more than 48 h per week, and their average was 35 years old. Seventy participants (thirty females and forty males) provided informed consent to participate in this research. The experts in the design or creation of spiritual environments with over 10 years of experience were invited to participate in the study.

The participants were interviewed separately in the same room using a semi-structured interview technique. Each participant was presented with ten images of stress-relieving buildings and interviewed for 40 min. The sample buildings were selected through a preliminary screening. The participants were likely to select buildings that they had previously visited or seen on the Internet or in their daily lives. The buildings were selected from Taiwan and Japan as the two countries have similar cultures.

We collected photos of 600 different buildings, removed their backgrounds, and divided them into three groups: public buildings, residential buildings, and religious buildings. We arranged these buildings using a matrix diagram and compared the color characteristics of Taiwanese versus Japanese buildings (Figure 4, Figure 5 and Figure 6). In Japan, 52% of the buildings used white, gray, and black colors, whereas only 24% of the buildings in Taiwan used these colors. The chromaticity of residential buildings in the two places was low in saturation, whereas the exterior chromaticity of religious buildings was high in saturation. The saturation of religious architecture in Taiwan was higher than that of Japan.

We asked experts in architectural design to select representative and relatively stress-relieving buildings. The three types of buildings were subdivided into buildings of high color saturation/high lightness or low color saturation/low lightness. In selecting architectural colors, we excluded buildings that were entirely white, black, or gray. At least 50% of the selected buildings had those colors as displayed in Figure 7, Figure 8 and Figure 9. We used a stress index scale (Health Promotion Agency, Taiwan Ministry of Health and Welfare) to select 10 office workers who had a stressful lifestyle (

Table 1. Ten participants with stressful lifestyles.

Code	Personal Profile	Code	Personal Profile
A1	Mr. Wu (Kaohsiung); Age: 40–45 Occupation: Firefighter	A6	Mr. Wu (Kaohsiung); Age: 40–45 Occupation: Marketing Specialist
A2	Mr. Lin (Tainan); Age: 30–35 Occupation: Career Soldier	A7	Miss Lin (Chiayi); Age: 25–30 Occupation: Executive Assistant
A3	Miss Chen (Tainan); Age: 30–35 Occupation: Freelancer	A8	Miss Pan (Taichung); Age: 35–40 Occupation: Soldier
A4	Miss Lin (Tainan); Age: 25–30 Occupation: Executive Assistant	A9	Miss Chen (Hualien); Age: 40–45 Occupation: Project Planner
A5	Miss Wang (Taichung); Age: 45–50 Occupation: Director	A10	Miss Chang (Pingtung); Age: 35–40 Occupation: Executive Officer

). These 10 participants selected a total of 420 stress relief-related adjectives using the Jiro Kawakita (KJ) method.

4. Discussion

4.1. Sample Analysis

With high levels of stress in learning, living, or work, the influx of new information can result in cognitive overload. Similarly, an excess of information, such as a building with overly complex colors, may cause stress, particularly if the building elements are interactive. Consequently, simpler buildings are favored by residents for stress-relieving effects. The participants evaluated the buildings using the stress index scale. Ten participants were identified with high-pressure lifestyles using the Jiro Kawakita (KJ) method and were tested to identify the major factors. A total of 420 words were collected and grouped into 15 adjectives.

Table 2. Top five words.

Adjective	Votes	Related
Comfortable	102	satisfied, easy, cozy, cheerful, quiet
Kindly	80	safety, peaceful, amiable, gentle, benevolent, beneficent
Friendly	73	nice, kind, heavenly, Steady
Simple	66	bright, plain, still
Fun	45	happy, colorful

presents the five most frequently words identified by the 10 participants, i.e., “comfortable”, “kindly”, “friendly”, “simple”, and “fun”.

Ten pairs of adjectives were chosen from the words collected, and the participant’s perceptions of the building images were measured (

Table 3. Sample statistics.

Project		Number of Times	%	Project			Number of Times	%
Gender	Male	30	42.9	Age		20 or below	2	2.9
	Female	40	57.1			21–30	26	37.1
Profession	Government Official	18	25.7			31–40	28	40
						41–50	10	14.3
	Administrative	17	24.3			50 or above	4	5.7
	Project assistant	12	17.2	Highest Education Level	Junior High School or below		3	4.3
	Business	3	4.3		General and vocational High School		12	17.1
	Self-employment	3	4.3		Post-secondary School		7	10
	Stewardship	1	1.4		University/College		37	52.9
	Others	16	22.9		Master or above		11	15.7

). The instructor introduced the evaluation process and clarified that the participants could express their feelings regarding the imagery in each photograph and select adjectives or preferences. This process was adopted to minimize the likelihood of the participant’s responses. As the adjective pairs were meaningful, a video was played while the participant performed the tests. Each video was displayed for 60 s. Following this, the participants selected their rating criteria. The results of the test indicated that the majority of participants perceived religious buildings as providing stress-relief, stability, and joy (Figure 10). A total of 73% of the participants indicated that buildings with lower color saturation provided larger stress-relief. Additionally, the participants indicated that residential buildings with simpler colors were perceived as more comfortable.

4.2. Attractive Factors

The three most prevalent feelings and their corresponding building forms are presented in

Table 4. Top 5 attractive feelings and their related initial reasons and concrete reasons.

Adjective	Color Image
Comfortable	Warm color; Value lightness: 0–3, 8–10; Saturation: 2–6
Kindly	Warm color; Value lightness: 6–10; Saturation: 7–9
Friendly	Warm color; Value lightness: 6–10; Saturation: 7–9
Simple	Warm color; Cool color; Value lightness: 0–3, 8–10; Saturation: 2–6
Fun	Warm color; Value lightness: 7–10; Saturation: 7–10

Remark: Black/0; White/10.

. Thirteen images were selected by the design experts as the most stress-relieving (

Table 5. Invited experts in this research.

Code	Personal Profile	Code	Personal Profile
B1	Miss Wu, Age: 45–50 Occupation: Professor	B6	Mr. Ho, Age: 60–65 Occupation: Professor
B2	Mr. Liu, Age: 40–45 Occupation: Professor	B7	Mr. Wu, Age: 45–50 Occupation: Professor
B3	Miss Li, Age: 40–45 Occupation: Designer	B8	Miss Pai, Age: 35–40 Occupation: Professor
B4	Mr. Lin, Age: 35–40 Occupation: Architect	B9	Miss Liu, Age: 40–45 Occupation: Designer
B5	Miss Chen, Age: 40–45 Occupation: Director	B10	Miss Chang, Age: 35–40 Occupation: Assistant Researcher

).

4.3. Buildings and Environmental Concerns

Architecture and built environments are conducive to stress-relief and mental health if they are designed with a consideration of the environment [20]. This is important for patients as some colors encourage activity, and others encourage rest. We used retouching software to remove things other than buildings. When the participants judged the color images, they were influenced by the impression of the environment and opinions affected by the imagination in their memory. Judgments about color images depended on their mood and involved various emotions affected by the color of the environment.

Architectural experiences are complex. Mental health is closely related to social ties and social capital. In other words, the emotions people experience may be influenced by emotional residue. Designers need to innovate and create functions to promote positive, safe, and natural interactions between people and foster a sense of community. It is difficult for an individual to describe the experience without an understanding of the architecture. The participants in this research experienced or visited the buildings before being tested. Thus, they had a basic judgment of the buildings. Building colors remained in the memory. The ambient color became a stressful color. The participants were also influenced by instructions. The purer the color of the building, the more it slows down the emotional fluctuation of the participants.

5. Conclusions

Today, more than 50% of the global population lives in cities, and this figure is predicted to rise to over 70% by 2050. Urban building and population density will keep increasing. Nonetheless, numerous studies revealed that cities are associated with an increase in risk to mental health, relative to rural areas; depression shows a 40% increase in risk, the risk for schizophrenia is doubled, and the risks for anxiety, stress, and isolation are increased considerably [21]. Therefore, designers must consider the design elements to reduce the influence of the reception of information.

The comparison of the exterior colors of buildings in Japan and Taiwan revealed that 93% of the participants were affected by changes in the color of buildings and the area. They did not prefer buildings with high brightness and chroma. In the second stage of the test, the color area of the buildings was reduced to 40% and the color types were reduced to fewer than four in number; the participants chose buildings with high brightness and high chroma. The test results revealed that excessive exterior color caused the participants to feel emotionally disturbed. That is, the amount of information increased the stress of the participants. Six hundred buildings revealed how a building’s appearance is influenced by culture. In other words, each country has its own colors for buildings. The chroma of buildings in Taiwan was between 7° and 8°, and the brightness was 8°–9°, whereas the chroma of buildings in Japan was between 6° and 7° and the brightness was 7°–8°.

An individual’s living space is shaped by their work and education. When designing urban buildings, it is also necessary to consider what practical tasks and activities the inhabitants engage in, in addition to creating a positive atmosphere. Beautiful shapes, colors, and feelings are design elements. Designers need to pursue self-realization and consider the changes and feelings of the environment. For example, Tadao Ando’s Chapel of Light and I.M. Pei’s Miho Art Museum present a sense of tranquility through the use of shapes and colors, all of which embody this concept. The present research results showed that the simplicity of architectural color use made the participants feel happier. The more complex the color used in the building, the more the information in the subjects’ brains increases. The simplicity of color depends on the variety and saturation of colors.

In this research, we created a preliminary design based on the experimental results. The quantity of color information influences psychological feelings, while the chroma of the color affects judgment. While buildings with color variations were perceived as enjoyable, they did not relieve stress, as people received more information. An overstimulating environment is characterized by the use of highly saturated colors and complex color combinations. It is important to achieve color harmony to minimize stress. The concept of color harmony is not based on personal preference but on the position of each color within a scientific color system. Color harmony is achieved when the eye is no longer seeking to balance colors. An understanding of color and color systems is important in architecture. The architectural design of a city represents a display of regional culture and life. However, it must not be a burden on people and increase their stress.