The Effect of Green Interior Programs for College Students with Developmental Disabilities on Plant Familiarity

Research subjects and period

Research subjects (participants) were recruited from the Department of Rehabilitation and Independence (Specialized Division of Developmental Disabilities) at N University, located in Cheonan. The department, targeting people with developmental disabilities, is divided into tracks based on the type of work they are interested in. Students enrolled in the Horticulture Track and taking a horticulture course were given an explanation about the greenterior program and how they could participate in the program as an exercise tied to the course. Written informed consent was obtained from students and their parents who agreed to participate in the program, and the program was implemented, targeting only such students. In addition, IRB verification of the program (IRB-Nazarene University-2023-37) was completed through deliberation by the N University Bioethics Committee. Class A, the experimental group, consisted of 15 participants who took the plant-related practical course. For Class B, the control group, although 17 students were selected from the same Specialized Division of Developmental Disabilities who did not participate in the program and instead took other courses that focused on general theory at the same time, only 15 students ultimately participated, as two who withdrew during the consent form completion process were excluded. The participants met the following criteria: Both participants and their guardians provided informed consent to participate in the program; the students were college students who met N University's academic ability standards and had a borderline or mild developmental disability (Level 3 Developmental Disability); and the participants held a registration card or welfare card for the disabled as per Article 32 of the Act on the Welfare of Persons with Disabilities. The gender composition was 11 males and 4 females for Class A, and 12 males and 3 females for Class B. The research personnel included a facilitator with a doctoral degree in horticulture, an assistant facilitator with a master's degree in rehabilitation, and a lecturer who majored in art.

Research design

The program consisted of 10 sessions with a three-stage structure, as follows. Taking into account cognitive, affective, and psychomotor/kinesthetic domains based on familiarity components, in the introduction stage of each session, space-related storytelling was used to establish rapport. In the development stage, greenterior items were produced based on what was understood through the storytelling. In the finishing stage, the focus was on arranging the space and utilizing the items. The program was scheduled for 10 sessions from October to November 2023 to allow for full implementation in connection with the course, excluding periods such as exams and orientation field training in the academic schedule. The program was intended not only to help CSDDs experience it and develop correct values about plants and their surroundings, but also to make it easier for them to understand space-related things through storytelling based on their interaction as speakers and listeners, thereby fostering their interest in the living environment and developing their design skills using plants. To this end, the program, with the structure of introduction, development, and finishing steps was designed in detail in consultation with the expert group (FGI), as shown in Table 1.

Table 1

Design of a greenterior program for college students with developmental disabilities

Program content

The content of the program was designed to enhance comprehension of space and plants by incorporating storytelling into each session. Sessions 1–3 covered the cognitive domain, which encompassed fundamental knowledge and general understanding of plants. Sessions 4–6, which comprised the middle stage, focused on allowing participants to express their emotions in the affective domain and become familiar with plants by creating aesthetic interior ornaments and applying them to space. Sessions 7–9 enhanced the psychomotor/kinesthetic domain through cooking activities that promote physical health, and creating works that require body coordination. Each session lasted for 2 hours, with an introduction (storytelling and preparation for practice) in the first class, and development (practice in making interior decorations) and finishing (space arrangement, presentation and cleanup) in the second class. Easy-to-access design techniques, such as printmaking, collage, image drawing, and miniature model production among art media, were appropriately used considering those who have difficulty drawing.

While conventional horticultural education focuses on plant cultivation and hands-on activities, this program, a greenterior program tailored to the needs of CSDDs, offers a unique approach through the following features. The program sought to improve participants' cognitive understanding by having them watch videos of plant use cases applied to different spaces and engage in conversations with researchers about each space in a storytelling manner. Furthermore, it encompasses the steps of having them create greenterior decorations and arrange them in spaces. Considering the cognitive, affective, and psychomotor/kinesthetic capabilities related to the detailed domains of plant familiarity in Table 2, a focus group of experts was consulted to obtain advice for this study. A review was also requested from professionals in the fields of horticulture, art, and rehabilitation with consideration of CSDDs' understanding. In this study, the classification of the detailed domains of plant familiarity into cognitive, affective, and psychomotor/kinesthetic tendencies was adapted for CSDDs, based on Lee's (2012) and Chung's (2020) classification criteria for plant familiarity of elementary school students. Table 2 shows the specifics of each session. The cognitive domain was divided into growing conditions, plant classification, and increased integrated thinking. The affective domain included emotional stability, stress management, and character development. The psychomotor/kinesthetic domain was divided into environmental and dietary effects. The specifics were created by referring to the data suggested by Bae and Park (2018) and considering the participant's performance abilities. During Session 1, participants were introduced to different types of plants through storytelling about the wonderful world of plants. They then observed a collected and dried Neprolepis obliterata, and used acrylic paint and a printmaking technique called planographic printing to stamp its shape and create hanging scrolls for wall decoration. In Session 2, after being presented with a story about how a house is made, participants constructed a house model using a kit and created plant sculptures using floral foam and Aspidistra elatior to arrange them in the model. This activity enhanced their understanding and integrated thinking about the relationship between space and plant sculpture. During Session 3, participants were presented with a story about the four seasons paired with trees to help them understand the four seasons from a plant physiological perspective and create color images of the four seasons with colored paper on canvas. This activity affected the cognitive domain by helping students understand growing conditions. Thus, framed canvas works were created using colored paper through a collage technique. During Session 4, after appreciating the stories of urban farmers through storytelling, participants created a mini garden using recycled materials that were discarded in urban areas. This activity enabled them to understand the benefits of urban gardens, and resource recycling. During Session 5, after enjoying storytelling about theme gardens and party decorations, participants created placemats using a flower-pressing technique, which can be used as table decorations for parties. During Session 6, participants were presented with a story about air purification in residential spaces and indoor gardens to aid their comprehension of terrarium principles. They were then tasked with creating a model of a residential space, and a terrarium to serve as decoration for a small indoor area. During Session 7, participants watched a video showcasing the botanical garden cafe and listened to a story about plants and health. They then created and tasted canapés with edible flowers and fruits, as well as vegetable salad. They also recreated a dessert cafe, a commercial space, and presented ideas for improving eating habits to promote physical health. During Session 8, participants were presented with a storytelling about fine dust and air purification. They were also provided an explanation of the effects of wall gardens for air purification, along with relevant examples. Finally, they were asked to create a framed moss topiary garden. During Session 9, participants were introduced to community gardens through a story about gardens that people wanted to share. They collaborated in groups to draw a blueprint for a garden they wanted to share, and then cooperatively constructed it. Notably, throughout the design process, they actively communicated through group discussions. In Session 10, participants presented a story about their dream garden they would like to have in the future, and arranged their completed works in the form of a mini garden.

Table 2

Investigation area of plant familiarity and question content

Assessment tool and analysis method

Pre-test for homogeneity between groups

Before the analysis, the final population size was 15 for the experimental group and 15 for the control group. Since the population size of each group was in the range of 10 to 30, the normality was checked. As a result, the following tests were used to confirm normality: in the Koimogorov-Smimov test, p = .167 > .05 for the experimental group and p = .200 > .05 for the control group; in the Shapiro-Wilk test p = .183 > .05 for the experimental group and p = .615 > .05 for the control group. Therefore, a paired t-test could be performed.

Table 3 shows the analysis results of the t-test performed to verify the homogeneity of the two groups, the control and the experimental groups, before the implementation of the greenterior program. As the three sub-domains of plant familiarity assessment in this study, the cognitive domain (p = .172), the affective domain (p = .066), and the psychomotor/kinesthetic domain (p = .165), as well as the overall plant familiarity were all p > .05, there was no significant difference in both groups. The p-value of Levene's test for homoscedasticity was p = .801 > .05 for the cognitive domain, p = .211 > .05 for the affective domain, p = .084 > .05 for the psychomotor/kinesthetic domain, and p = .052 > .05 for plant familiarity. In other words, the control and the experimental groups were found to be homogeneous, so this study could proceed.

Table 3

Pre-test for homogeneity of the green interior program in control and treatment groups

Within-group pre- and post-test

After implementation of the greenterior program, the three sub-domains of the plant familiarity assessment (cognitive, affective, and psychomotor/kinesthetic domains) and the overall plant familiarity of the control and experimental groups were analyzed using a paired t-test. For the control group, it was found that there were no significant differences in any of the domains: cognitive domain (p = .294), affective domain (p = .856), psychomotor/kinesthetic domain (p = .130), and plant familiarity (p = .795). Meanwhile, the experimental group showed statistically significant differences in all sub-domains after the greenterior program: cognitive domain (p = .000), affective domain (p = .000), and psychomotor/kinesthetic domain (p = .000), and plant familiarity (p = .000). In other words, the greenterior program had a positive effect on both plant familiarity and all sub-domains of CSDD.

Plant familiarity

For the greenterior program, we chose the dormitory of N University, which is a living experience type space rather than a classroom, as the training site with the aim of using plants in living spaces. It seems that students could gain familiarity with plants more easily than in theoretical classes by practicing spatial design activities closely related to daily life. This involved using the kitchen and living room to decorate the space with plants, including table decorations and planteriors, as well as making interior accessories. Notably, this is consistent with the finding that these life-related programs stimulated active participation among elementary school students as they increased their concentration and grew their interest in plants and learning (Lee, 2012). It appears that CSDDs' familiarity with plants was naturally increased as they were exposed to plants in their daily lives, which increased their concentration (Kim, 2020). In addition, this result (Table 4) can be interpreted based on the report that the level of developmental disability of the participants in this study (Level 3 Developmental Disability) is equivalent to that of a third grade or higher student in elementary school (Park, 2018). Consequently, it was confirmed that the greenterior program, which focuses on the use of living space, is effective in promoting participants' interest in and familiarity with plants.

Table 4

Before and after-greenterior program comparison of the plant familiarity in control and treatment groups

Cognitive domain

As shown in Table 5, the experimental group showed significant improvements in the cognitive domain, while the control group showed no significant changes. It appeared to contribute to cognitive improvement to understand the space for greenterior design and utilize plants by drawing a floor plan, observing the surroundings to select plants, or drawing and coloring. This result is supported by the findings of Kim (2022) that botanical art programs, which involve detailed observation and drawing, have an effect on participants' recognition of plant species and growing conditions, and that drawing detailed pictures of plants increases their integrated thinking. It is also consistent with findings suggesting that programs using art media have an effect on improving the cognitive abilities of adolescents with developmental disabilities (Park, 2010). Notably, it seems to be supported by Relf's (1981) theory. According to Relf's theory, through horticultural therapy programs, participants learn new knowledge, enjoy storytelling about space with their friends, and then talk about and interpret what they have observed. This allows them to develop their judgment and situational coping skills, and naturally learn how to manage plants, thereby improving their intellectual abilities.

Table 5

Before and after-greenterior program comparison of the cognitive domain in control and treatment groups

Affective domain

The improvement results in the affective domain, as shown in in Table 6, seem to be in line with the results of many previous studies, including the findings: that through a program with nature, the participants developed their character and stabilized their emotions while decorating a living space together, sharing opinions, and understanding each other (Chung, 2020), and that growing and caring for plants develops character traits including responsibility and consideration (Jang, 2019; Kim, 2020; Kwack et al., 2007). In addition, it seems that decorating a living space with decorations that incorporate plants increases psychological satisfaction with the space, thereby creating a sense of stability, and that organizing and beautifying one's surroundings ultimately helps cultivate positive emotions. This is consistent with the suggestions that modern people are highly interested in design and aesthetic environments (Lim, 2007), and that their emotions are stable in aesthetic environments (Park, 2010). In addition, it is also in line with previous study findings suggesting that horticultural therapy programs with plants affect emotional stability and personality (Jang et al., 2015). It seems that handling plants creates an attitude of respect and care for life, which improves the affective domain. Meanwhile, in terms of emotional stability, plants promote the generation of alpha waves in the brain, and looking at green plants has the effect of reducing tension and alleviating various stress indicators, including pulse, blood pressure, skin, and the stress hormone, cortisol (Kwack, 2007). Kwack's findings seem to scientifically support this study's finding that the greenterior program is effective for emotional stability.

Table 6

Before and after-greenterior program comparison of the affective domain in control and treatment groups

Psychomotor/kinesthetic domain

The psychomotor/kinesthetic domain refers to sub-domains including health, and skilled, professional, and artistic functions among the domains of human behavior change (cognition, affective, and psychomotor/kinesthetic domains) pursued through education (Chung, 2020). Accordingly, psychomotor/kinesthetic satisfaction with the program, as shown in Table 7, seems to result from the following: introducing the story of a dessert cafe space using fruits and vegetables to the program and providing it to the participants in a storytelling manner, and allowing them to experience dining spaces by making canapé desserts with edible flowers, as well as fruit salads, and table decorations. Notably, after observing botanical garden cafes online, the participants enlivened the dormitory of N University, a living experience space, with the atmosphere of such a cafe by engaging in food styling using tea and dessert as table decorations. In this manner, it appears that promoting their understanding by explaining the relationship between the atmosphere of the dining space and health to them through a story served to increase their interest in health. Moreover, it seems that cooking and eating food together in the process of creating table decorations with plants increased high psychomotor/kinesthetic satisfaction. Allowing the participants to decorate tables, among the greenterior spaces, with fruits and vegetables, and educating them about nutritional values such as "nutrition from the garden," while including health-related information, may also be related to the high levels of satisfaction. Furthermore, this result seems to be supported by reports on the health effects of such programs (Kwack et al., 2007). Meanwhile, considering the psychomotor/kinesthetic domain is related to physical and mental health, and the greenterior program requires substantial hand-eye coordination in the process of arranging spaces, the result can be seen as consistent with those of a previous study reporting that gardening activities are related to the body and help develop coordination and balance between the eyes, hands, and feet, as well as sense of space and gravity. In addition, their increased interest in and understanding of the indoor environment and health, through the wall greening session in relation to air purification, seem to have led to the high improvement shown in Table 7.

Table 7

Before and after-greenterior program comparison of the psychomotor/kinesthetic domain in control and treatment groups