How to Enhance Consumer’s Engagement with Returnable Cup Services? A Study of a Strategic Approach to Achieve Environmental Sustainability

Abstract

The issue of sustainability has once again received attention and promotion in the post-COVID-19 pandemic era. Countries worldwide have launched returnable cup services for beverages, such as Taiwan, which is a highly developed market for hand-shaken drinks, and various beverage and convenience stores have been gradually launching this service. However, reasonable usage rates have yet to be achieved. This study aimed to explore the psychological cognition of using a returnable cups service by understanding the motivation affecting the behavior intention through external and internal influencing and categorizing realistic cognition, which observes the motivating factors from three perspectives: passively acquired awareness, autonomous consciousness, and perception in real life for further achieving environmental sustainability. Research found that when consumers’ environmental awareness is insufficient to sacrifice convenience, it is necessary to employ a service strategy design for passive influence. The focal point for influencing consumer attitudes lies in the backend of services, particularly in cup return, which is the chain-closing juncture. The result can provide the beverage industry and governments with a reference to promote returnable cups and contribute to plastic reduction in sustainable development.

1. Introduction

Environmental protection has now become a huge challenge for countries all over the world due to the delay and impact of the epidemic, where the entire expected progress of environmental protection has fallen far behind. Beverages, including coffee, have become indispensable spiritual sustenance in modern human life. It is customary for individuals to enjoy beverages while walking on the streets, where the impact of this imagery reverberates deeply within the collective consciousness. Hand-shaken drinks, such as bubble tea and coffee, have surged in popularity around the world, especially in Taiwan, where the tea culture is very popular. This cultural phenomenon not only underscores Taiwan’s rich culinary heritage but also serves as a potent reminder of the interconnectedness between food culture and environmental sustainability [1,2]. Since late 2019, there has been a notable surge in demand for single-use containers, fueled by heightened hygiene concerns and precautionary measures [3,4,5]. Over 80% of marine litter comprises plastics, which is a statistic underscored by the European Parliament (28 May 2018). This pervasive presence of plastic debris poses multifaceted threats by not only inflicting harm upon oceanic species but also permeating the human food chain through ingestion by organisms after decomposition.

Consequently, numerous countries have instituted plastic restrictions and substituted plastic cups with paper cups. However, despite this shift, a staggering 90% of paper cups are in landfills. This paradox arises because the interiors of paper cups are often coated with a thin layer of polyethylene film, which is essential for preventing leakage but renders the cups non-biodegradable [5,6,7,8,9,10]. Foteinis [8] further underscored the issue by noting that paper cups often find their way into landfills or are improperly disposed of, resulting in the generation of (micro)plastic waste. Importantly, Foteinis highlighted the inadequacy of the current life cycle impact in accurately quantifying the environmental impact of paper cup disposal. This acknowledgment prompts a critical reevaluation of existing environmental evaluation methodologies. Consequently, Foteinis suggests that prioritizing the reuse of existing cups emerges as a potentially optimal strategy for optimizing ecological protection efforts.

As such, in Taiwan, which is the source region of hand-shaken drinks, in response to these pressing environmental concerns, the government took proactive measures by instituting the returnable cup (or circular cup) loan service regulation in convenience stores and fast food restaurant chains, effective 1 January 2023. Ms. Zhang, the Director of the Greenpeace Plastic Reduction Program, as cited by Chen [11], highlighted the significant environmental benefits associated with the reuse of returnable cups, where each returnable cup reused 20 times annually can yield impressive reductions, including decreases of 25.4% in carbon emissions, 36.9% in water consumption, and 36% in suspended particulate generation. Moreover, the environmental gains would be substantial if returnable cups were to entirely replace the four billion single-use plastic (SUP) beverage cups consumed annually in Taiwan. This transition would reduce the use of 344,000 barrels of oil, which is the water consumption equivalent to 255 Olympic swimming pools, and the carbon emissions akin to those of 240,000 motorcycles. These figures underscore the potential for returnable cups to serve as a sustainable alternative with far-reaching environmental benefits. However, according to an investigation by the Greenpeace organization [12], although the awareness of returnable cup services is high, with 96% of respondents reporting familiarity, only 31% utilized the service. Moreover, it revealed that despite 103,343 returnable cups being rented out in the first half of 2023, this represents less than 1% of total beverage cup usage in Taiwan. Although the onset of the pandemic initially led to a surge in bringing personal cups due to hygiene concerns, convenience has gradually resurfaced as a dominant factor in consumer behavior as the pandemic wanes. Consequently, disposable cup usage has rebounded as people revert to familiar habits in their daily lives.

This study aimed to explore strategies to improve consumers’ use of returnable cups, thereby reducing the generation of SUPs that cause undecomposable waste. This study was bifurcated into two components, with the aim to delve into the psychological aspects surrounding using returnable cup services. First, it sought to unravel the motivations behind behavioral intentions by scrutinizing external and internal influencing factors. Second, it endeavored to categorize realistic cognition. Returnable cup services entail cup-rental services offered in conjunction with beverage purchases. As depicted in Figure 1, the consumer initiates the process by ordering a beverage and opting for a returnable cup. When the returnable cup service was first launched, some surveys showed that hygiene issues were one of the factors that prevented consumers from using it. However, soon after, companies came forward to explain and demonstrate the clearance process to eliminate the doubts. Therefore, the present study temporarily excluded considerations related to hygiene factors. As highlighted at the outset of this article, consumers exhibit a heightened awareness of the consequences and responsibilities associated with plastic waste, actively seeking solutions. To effectively advance the overarching waste and plastic reduction objective, it becomes imperative to comprehend consumers’ attitudes, challenges, and motivations concerning cup recycling.

2. Materials and Methods

First, it is necessary to define the experimental object. Various terms such as “recyclable”, “reusable”, or “returnable” are prevalent in the market. Recycling or reusing typically encompasses all containers without specifying ownership. This study adopted the term “reusable” to denote containers owned by the company, necessitating their return to complete a service cycle. This study employed the norm-activation method (NAM) to explore the physiological and psychological cognition associated with using returnable cup services. Achieving a sustainable future depends on individuals making changes to reduce environmental damage [13]. In the literature, many scholars indicate that environmental awareness or green-related products can increase consumers’ behavior change [13,14,15]. Boks [16] and Coskun et al. [15] further point out that a higher negative impact on the environment has a higher chance of influencing consumer behavior, and changing behavior through design may help to deliver greater environmental benefits. Therefore, this study applied the NAM to explore the characteristics that make consumers feel responsible for negative impacts and how environmental sustainability responsibility stimulates behavioral changes. Additionally, it applied the Kano model to categorize the quality attributes of convenience factors, aiming to identify, rectify, and enhance the usability of returnable cups. The ultimate goal was to stimulate consumption behavior and foster environmental sustainability. Figure 2 illustrates the research framework. The variables incorporated within the NAM framework are potent tools for elucidating the multifaceted nature of prosocial intentions and behaviors within social and environmental contexts [17]. Concurrently, the Kano model offers a robust methodology for assessing customers’ genuine sentiments regarding specific product or service attributes [18]. Through the synergistic application of these methodologies, this study endeavored to comprehensively understand consumer attitudes and behaviors toward returnable cup services to optimize their efficacy in promoting sustainable practices.

2.1. NAM

The NAM is often applied in studies of pro-environmental behavior [19] and is widely used to predict and investigate pro-environmental and pro-social behaviors [20,21]. It mainly explains behavioral intentions from the perspective of individual consciousness [22,23,24]. In recent years, many scholars have applied these models to study reusability and other related issues [23,25,26,27,28], indirectly illustrating the applicability of this model for predicting environmental attitudes. The norm activation model (NAM) explains the conditions within which altruistic behavior is fostered. It enhances individuals’ proclivity to engage in behaviors predicated upon a conscientious recognition of the detrimental ramifications of their actions [29,30]. Central to the NAM is the advocacy for individuals to subsume their interests to advance the collective welfare, embodying the ethos of altruism [31,32,33].

Schwartz [33] delineated a tripartite framework comprising personal norms (PNs), awareness of consequences (AC), and ascription of responsibility (AR) as pivotal determinants shaping behavioral intention (BI), as illustrated graphically in Figure 3 within the NAM. AC refers to whether someone is aware that not acting pro-socially will negatively impact other people or other important things. [17,34], while AR signifies acknowledgment of the environmental ramifications stemming from disposable cup usage [35]. PNs, conversely, encapsulate moral imperatives dictating behavioral choices. Song et al. [26] pointed out that enlightening consumers about the adverse repercussions of eschewing reusable packaging can effectively bolster their moral obligations and enhance motivational drives. The NAM demonstrates two primary interpretative paths, notably the sequence linearity model and the intermediate model, wherein AC and AR directly influence PNs. Klöckner [36] underscores the relevance of AC and AR within this context. This study adopted the intermediate model to elucidate the intricate interplay between these factors and posited the following hypotheses:

H1: 

The consumer’s AC influences AR toward using a returnable cup.

H2: 

The consumer’s AR influences PNs toward using a returnable cup.

H3: 

The consumer’s PNs influence BI toward using a returnable cup.

H4: 

The consumer’s AC influences PNs toward using a returnable cup.

2.2. Convenience of Use (CU)

High quality of life and convenience are integral aspects of daily living, and thus, the standards for service convenience are correspondingly elevated. Against this backdrop, the convenience of services has emerged as a significant factor in attracting customers. Indeed, convenience serves as a pivotal driver of positive action [38,39]. Convenience in service is intricately tied to consumers’ perceptions of the time, effort, and cost associated with utilizing a particular service. It aims to streamline the consumer experience, minimizing cognitive, emotional, and physical exertion during engagement [39,40,41]. Convenience in service provision not only enhances consumer comfort levels [42] but also revolves around the efficiency of decision-making processes regarding service utilization and selection among competing alternatives [43].

The perception of convenience throughout the service encounter stands as a key determinant of service quality. Extensive research suggests that minimizing the time and effort expended by customers correlates positively with the convenience they perceive, thereby amplifying the overall value derived from the service [44]. Furthermore, empirical evidence underscores that a dearth of convenience ranks prominently among the reasons for customer defection, emphasizing its pivotal role in nurturing enduring relationships [45,46,47]. Remarkably, service convenience directly influences consumers’ behavioral inclinations [48,49,50]. Within the purview of this study, convenience was construed as an extraneous factor that shaped consumers’ intentions to utilize returnable cups. Thus, the following hypothesis was posited:

H5: 

The consumer’s CU influences the BI toward using a returnable cup.

2.3. Environmental Concern

Environmental concern (EC) represents an emotional attitude toward the severity of environmental issues [51,52,53]. A poignant example highlighting the urgency of environmental concerns is the Great Pacific Garbage Patch, which is an area estimated to be as expansive as a continent, littered with disposable plastic containers and other discarded materials, containing over 79 thousand tons of plastic in the Pacific Ocean [54,55]. Studies indicate that reused container systems offer a more favorable environmental footprint compared with disposable cups [56]. However, one of the foremost challenges in attaining ecological sustainability lies in encouraging consumers to adopt returnable cup systems. Globally, countries are implementing ecological protection and green policies to safeguard the environment, thereby indirectly compelling companies to assume greater social responsibility [57]. Major chain enterprises, such as Starbucks, McDonald’s, Burger King, and 7-11, have taken the lead in implementing returnable cup services, either through internal initiatives or in collaboration with other entities. Prior research demonstrated that environmental concern can significantly influence intentions toward environmentally sustainable behavior [5,26,53,58]. However, some studies indicate that environmental concern may not exert a direct influence or may serve as an intermediary variable [59,60]. Considering this, the hypotheses of this study posited that environmental concerns directly motivate the behavioral intention to use returnable cups, formulated as follows:

H6: 

The consumer’s AC influences the EC toward using a returnable cup.

H7: 

The consumer’s EC influences the BI toward using a returnable cup.

3. Research Methodology

3.1. Questionnaire Design

Data collection for this study involved utilizing a two-part structured questionnaire to understand and evaluate the impact of environmental responsibility and convenience on behavior change. The first part drew upon insights from past NAM-related literature to establish a psychological pathway structure. The questionnaire was divided into internal factors, including AC, AR, PNs, and EN, and external factors, including BI and CU. The questionnaire design mainly referred to the content of recent and high-quality journal research on environmental sustainability and product reuse issues [26,61,62,63], convening further focus groups for the question selection. The focus group members included three professors in environmental, design, and strategy design fields and three PhD students majoring in strategy design. After collecting the questions from the questionnaires, representative questions were selected by the focus group to form the questionnaire for this study. Utilizing a seven-point Likert scale, the questionnaire was designed in reverse to avoid the risk of invalid responses and facilitate subsequent validity assessment. The questionnaire was distributed in Mandarin, while the questions presented were in English to accommodate language requirements.

The second part of the data collection involved generating questions through in-depth interviews to explore realistic perspectives from consumers. Six interviewees from the beverage industry were selected (the information is shown in

Table 1. In-depth interviewee information.

Company	Gender	Title	Work Experience (y)	#
McDonald’s	F	Duty manager	3	1
McDonald’s	M	Duty manager	2	2
Starbucks	F	Duty manager	5	3
Starbucks	F	Employee	3	4
Starbucks	M	Employee	2	5
Bubble tea	F	Employee	2	6

) comprising employees from establishments such as Starbucks and McDonald’s, individuals deeply engaged in the hand-shaken drinks sector, and consumers with prior experience using returnable cups. The criteria for selecting interviewees were confined to individuals who had served the company for at least two years. This stipulation was intended to ensure that they had engaged with sufficient consumers and possessed a comprehensive understanding of the consumption ecology related to returnable cups. The beverage industry interviewees were asked about usage status, difficulties encountered during promotion, and possible factors that may cause promotion difficulties; interviewees with experience using returnable cups were prompted to articulate their sentiments regarding the service and elucidate the reasons behind their decision not to use it. The result of the in-depth interview, which is shown in

Table 2. Results of in-depth interview.

Mentions Times	Factors
4	There are too few return points, which is inconvenient.
3	The overall return process is very inconvenient.
3	Returnable cups are easier to carry than to-go paper cups, so I would like to use them.
3	Customers find the service process troublesome.
3	Do not want to run back to the store just to return the cup for a special occasion.
2	Customers are worried about hygiene issues.
2	They do not want to use it because if they forget or do not have the time to return, the deposit will be deducted.
1	We can return the cups at 7–11, but not all of them. It depends on whether the store is a franchise or directly operated. Two stores also have membership requirements, so consumers feel it is complicated.

Factors in the gray area were eliminated due to too few mentions and were eliminated through focus groups.

, clearly stated that convenience affected consumers’ willingness to use the service, and we included more than half of the jointly presented results as questions in the questionnaire, which were portability, the convenience of the returns process, and whether the cup collection station was located close to home. Please refer to

Table 3. Measurements variables in the questionnaire.

Category	Item	Factor	References
Awareness of consequences (AC)	AC1	Using returnable cups can improve the environment.	[26]
	AC2	Using returnable cups is environmentally friendly.
	AC3	Using returnable cups can reduce pollution.
Ascription of responsibility (AR)	AR1	I feel partly responsible for the environmental problems caused by using single-use plastic (SUP) cups.	[26,64]
	AR2	I believe that consumers share some responsibility for the environmental problems associated with SUP cups.
	AR3	Because I do not use returnable cups, I feel jointly responsible for the environment’s pollution and ecological damage.
Personal norms (PNs)	PN1	I feel it is my moral obligation to use returnable cups.	[26,63,65]
	PN2	Even if other people do not use returnable cups, I feel obligated to do so.
Environmental concern (EC)	EC1	Environmental problems are of great importance to me.	[26,66]
	EC2	There is no way we can ignore the problems associated with the environment.
	EC3	It is important that we take care of the environment.
Convenience of use (CU)	CU1	I think the current service model of returnable cups is convenient.	[61,62]
	CU2	I think location where you can rent returnable cups are quite common.	[63]
	CU3	I think the portability of the returnable cup is convenient.	Interview
	CU4	I think the return process of the returnable cup service is convenient.
	CU5	I thought it would be easy to take the rental returnable cups to a returning point.	[63]
	CU6	There are many returnable cup collection sites near my home.	Interview
Behavioral intention (BI)	BI1	I will use the returnable cups.	[26,29]
	BI2	I like the idea of returnable cups
	BI3	I plan to use the service of returnable cups in the future.

for the consolidated questionnaire.

3.2. Participants

The data were collected in Taiwan, the birthplace of hand-shaken beverages, which boasts one of the highest consumption densities globally. Participants were recruited via Tator, which is an online questionnaire distribution platform, in collaboration with Surveycake. Interviewees who completed the online survey received a nominal monetary reward to incentivize participation. A total of 600 questionnaires were gathered, and subsequent screening led to excluding 29 invalid responses, finally producing 571 valid questionnaires. The initial analysis involved conducting preliminary descriptive statistics on the returned questionnaires. Responses that violated the reverse question format or exhibited insufficient data (e.g., consistently selecting the same or predominantly similar scores) were rigorously screened and omitted from this study. Ultimately, the analysis was based on 571 valid samples.

3.3. Data Analysis

The collected data were subjected to analysis using both SPSS 29 and Smart PLS 4.0 software to compute the relevant paths. Structural equation modeling (SEM) and confirmatory factor analysis (CFA) were employed, which integrates both structural and measurement models, allowing for the simultaneous simulation of multiple regression equations [29,67]. SEM facilitates the examination of intercorrelations between a series of constructs represented by multiple variables, enabling the assessment of the statistical significance of construct weights and path coefficients [68,69]. Previous studies within the field of reusable containers and sustainability successfully applied PLS-SEM [53,69,70,71]. CFA is frequently employed to assess the structural integrity of observed variables [72,73], which is a widely recognized method for substantiating the construct validity in the development of instruments grounded in theoretical frameworks [74]. It is different from EFA, where CFA is mostly used for theoretical verification after the completion of a developed scale, and the NAM is a mature and widely used theoretical model. Therefore, PLS-SEM and CFA were deemed the most appropriate methodologies for this study, allowing for a comprehensive examination of the relationships between various constructs and variables of interest.

3.4. Kano Model

The Kano model represents a well-established framework utilized for identifying attribute quality and enhancing corresponding services. Rooted in customer-driven principles, the model is centered on addressing customer concerns [75]. Traditionally, discussions surrounding consumer satisfaction have been based on a one-dimensional function, wherein service quality directly correlates with satisfaction levels. However, Kano et al. [76] introduced the Kano model to overcome the limitations of linear assumptions by incorporating psychological qualities. This two-dimensional model demonstrates the nuanced relationship between quality attributes and satisfaction levels. Within the Kano model, five quality categories are delineated: attractive, one-dimensional, must-be, indifferent, and reversal, as depicted in Figure 4. To capture actual issues and discern effective factors, this study conducted a questionnaire survey aimed at investigating the attributes that influenced behavioral intention to use returnable cups. Subsequently, the Kano model was applied to classify the attributes of each convenience factor and assess their existing quality. This approach serves to provide insights into the quality of attributes and guide improvements in service delivery.

In the Kano model, attributes (qualities) are classified into three main observation indicators, each exerting a distinct influence on consumer satisfaction. Additionally, indifference and reversal qualities constitute two further types of quality, providing a comprehensive framework for understanding customer preferences and satisfaction. These classifications provide a structured approach for assessing and managing customer expectations, thereby guiding product and service development efforts to enhance customer satisfaction and loyalty. Here is an explanation of the five types of qualities:

• Attractive qualities (A): These attributes are initially perceived as insignificant, meaning their presence or absence does not notably affect satisfaction. However, when the performance of these attributes becomes significant, satisfaction is greatly enhanced. Essentially, these qualities have the potential to delight customers when present.
• Must-be qualities (M): Must-be qualities represent fundamental attributes that customers expect as a minimum requirement. When these qualities perform at a satisfactory level, satisfaction remains unchanged, but failure to meet expectations can lead to significant dissatisfaction.
• One-dimensional qualities (O): One-dimensional qualities exhibit a linear relationship with satisfaction. Higher performance levels lead to increased satisfaction, while lower performance levels result in decreased satisfaction. These qualities typically align with customer expectations and form the basis of competitive advantage.
• Indifference: Indifference signifies that the quality attribute is unaffected by changes in performance. Whether the attribute performs well or poorly, it has little to no impact on overall satisfaction.
• Reversal: Reversal qualities represent a unique scenario where high performance actually diminishes satisfaction. In other words, exceeding expectations in these areas can lead to reduced satisfaction levels.

4. Results

Descriptive demographic information pertaining to the participants is presented in

Table 4. Descriptive statistics of questionnaire participants.

Variable	Category	Frequency	Percent
Gender	Male	293	51.3%
	Female	278	48.7%
Age	18–24	98	17.2%
	25–34	159	27.9%
	35–45	175	30.6%
	More than 45	139	24.3%
Education	High school or under	148	25.9%
	Bachelor’s	346	60.6%
	Master’s or higher	77	13.5%
Experience of using returnable cups	Yes	334	58.5%
	No	237	41.5%
Frequency of drinking beverages (cups/week)	1–3 times	404	70.8%
	4–7 times	119	20.8%
	More than 8 times	48	8.4%

. Table 4 indicates a balanced distribution between male (51.3%) and female (48.7%) participants. The majority of participants within the age range of 25 to 45 years (58.5%), suggesting a predominant representation of individuals who were already established in their careers, likely holding bachelor’s degrees. Notably, more than half of the participants reported having prior experience with returnable cup services.

4.1. Measurement Model Analysis

Confirmatory factor analysis (CFA) was conducted on the overall questionnaire to evaluate the fitness, reliability, and validity of the measurement model prior to commencing the analysis process. The inner model is depicted in Figure 5, while detailed fitness metrics obtained from this analysis are presented in

Table 5. Structure fitness metrics.

Factor	Item	Λ	VIF	AVE	CR (rho_a)	CR (rho_c)	Cronbach’s α
Awareness of consequences (AC)	AC1	0.907	2.598	0.804	0.879	0.925	0.878
	AC2	0.907	2.686
	AC3	0.875	2.129
Ascription of responsibility (AR)	AR1	0.855	1.924	0.739	0.826	0.895	0.824
	AR2	0.887	2.091
	AR3	0.838	1.69
Personal norms (PNs)	PN1	0.903	1.637	0.812	0.768	0.896	0.768
	PN2	0.9	1.637
Convenience of use (CU)	CU1	0.791	1.736	0.64	0.905	0.924	0.889
	CU2	0.798	2.245
	CU3	0.786	1.912
	CU4	0.829	2.476
	CU5	0.815	2.544
	CU6	0.778	2.371
Environmental concern (EC)	EC1	0.872	1.993	0.727	0.812	0.889	0.812
	EC2	0.849	1.764
	EC3	0.836	1.684
Behavioral intention (BI)	BI1	0.899	2.456	0.743	0.828	0.896	0.826
	BI2	0.806	1.534
	BI3	0.879	2.303

. All factors demonstrated satisfactory reliability, with Cronbach’s α values exceeding the recommended threshold of 0.7, as suggested by previous studies [77,78,79]. Additionally, all factor loadings surpassed the acceptable level of 0.5 [80], indicating strong relationships between the observed variables and their respective latent constructs. As a precautionary measure, a multicollinearity examination was conducted. All variance inflation factor (VIF) values were found to be smaller than the threshold of 3.3 suggested by Kock and Lynn [81], signifying the absence of multicollinearity issues. Lastly, the standardized root-mean-squared residual (SRMR) and normed-fit index (NFI) were assessed. The SRMR value of 0.063 and NFI value of 0.818, as suggested by Hair et al. [82], indicated a good fit for the measurement structure utilized in this study, further confirming its suitability for subsequent analysis.

The hypotheses were rigorously tested through bootstrapping with 5000 iterations to assess the r-square values, parameter coefficients, and t-statistics. The results of these analyses are presented in

Table 6. Direct effect of bootstrapping PLS-SEM.

Direct Effects	β	M	SD	t	p
H1: AC → AR	0.511	0.511	0.043	11.863	0
H2: AR → PNs	0.554	0.554	0.036	15.603	0
H3: PNs → BI	0.404	0.403	0.042	9.605	0
H4: AC → PNs	0.186	0.187	0.039	4.724	0
H5: CU → BI	0.257	0.259	0.037	6.957	0
H6: AC → EC	0.495	0.495	0.036	13.741	0
H7: EC → BI	0.201	0.201	0.041	4.894	0
Indirect Effects
AC → AR → PNs → BI	0.114	0.114	0.017	6.704	0
AC → PNs → BI	0.075	0.075	0.018	4.079	0
AC → EC → BI	0.099	0.099	0.021	4.654	0

. The significance of the correlation between constructs, as indicated by the t-statistics and p-values, serves as a crucial determinant in accepting or rejecting hypotheses [83]. By scrutinizing these statistical measures, researchers can ascertain the strength and direction of relationships between variables and determine the validity of proposed hypotheses.

The structural equation modeling (SEM) analysis of this study yielded several noteworthy findings. First, it was confirmed that both paths of the norm activation method (NAM), namely, the sequence linearity model and the intermediate model, exerted significant effects on behavioral intention. However, the influence of the sequence linearity model (β = 0.114, t = 6.704, p < 0.01) was found to be considerably greater than that of the intermediate model (β = 0.075, t = 4.079, p < 0.01). Specifically, the direct paths exhibited strong coefficients (H1: AC → AR: β = 0.511, t = 11.863, p < 0.01; H2: AR → PNs: β = 0.554, t = 15.603, p < 0.01) compared with H4 (AC → PNs: β = 0.186, t = 4.724, p < 0.01), indicating that the ascription of responsibility played a crucial role in influencing behavioral intention. This finding was further consistent with the intermediate model proposed by Schwartz (1977), thus affirming the acceptance of H1 to H4 with excellent explanatory power. Second, the convenience of use was found to have a significant effect on behavioral intention (β = 0.257, t = 6.957, p < 0.01), indicating that the convenience of using returnable cup services did indeed influence consumer behavior intention, thereby confirming the acceptance of H5. Lastly, awareness of consequences was found to exert a significant indirect effect on behavioral intention through its impact on environmental concerns. Specifically, awareness of consequences positively affected environmental concern (β = 0.495, t = 13.741, p < 0.01), which, in turn, influenced behavioral intention (β = 0.201, t = 4.894, p < 0.01) with an indirect effect of β = 0.099, t = 4.654, p < 0.01. Thus, both H6 and H7 were accepted. It is noteworthy that while the comprehensive path (AC → EC → BI) did not exhibit as significant an influence as environmental concern alone, it was observed that awareness of consequences positively affected consumers’ environmental concerns.

4.2. The Kano Model Subjective Quality Attributes

Furthermore, this study delved into consumers’ attitudes regarding the convenience of using returnable cups by conducting the Kano model for data analysis. The analysis aimed to comprehend perceptions and attitudes toward returnable cup convenience among two distinct groups: those with no prior experience (novices) and those with experience. This division facilitated a nuanced understanding and informed strategies for future improvements.

Table 7. Summary of the Kano model results.

	Experienced Consumer					Novice
	β2 (+)	β2 Sig.	β1 (−)	β1 Sig.	Kano Category	β2 (+)	β2 Sig.	β1 (−)	β1 Sig.	Kano Category
CU1	0.197	*	−0.321	*	O	0.154	*	−0.207	*	O
CU2	0.127	*	−0.118	NS	A	0.156	*	−0.087	NS	A
CU3	0.193	*	−0.213	*	O	0.186	*	−0.141	*	O
CU4	0.200	*	−0.210	*	O	0.198	*	−0.051	NS	A
CU5	0.127	*	−0.196	*	O	0.263	*	−0.020	NS	A
CU6	0.159	*	−0.065	NS	A	0.213	*	−0.016	NS	A

O = one-dimensional quality; A = attractive quality; * = significant; NS = non-significant.

delineates the results of this analysis. For both groups of consumers, the convenience of the returnable cup service and its portability exhibited one-dimensional attributes, indicating a linear relationship between service quality and consumer satisfaction. The prevalence of rental stations and return sites emerged as an attractive attribute for both consumer segments. Interestingly, the attitude toward the convenience of returning returnable cups differed between experienced consumers and novices. While experienced consumers perceived this aspect as a one-dimensional attribute, novices viewed it as an attractive attribute. This disparity may serve as an entry point for novices to initiate their engagement with returnable cups.

5. Discussion

Services and interactions have escaped the impact of the epidemic and returned to people’s real lives. Three aspects influence the behavioral intention to use returnable cups: passively acquired awareness, autonomous consciousness, and real-life perception. Passively acquired awareness means awareness generated through the stimulation of negative consequences from the outside world, and autonomous consciousness means positive environmental awareness that is originally generated from the consumer. The results from the PLS-SEM indicated that the NAM in the sequence linearity model offered better interpretability than in the intermediate model. This path suggests that consumers generated a sense of responsibility by recognizing the consequences of using single-use plastic cups, which drove behavioral intention through moral obligation. If consumers failed to feel this responsibility, the consequences had a relatively minor impact on their moral obligation. Second, subjective environmental concerns arose from consequences that affected behavioral intention, which was more positive and consciously different from the NAM and was likely the result of self-blame, indicating that the environmental concerns may require individuals with a higher ecological awareness to change the behavior. These results also echo previous scholars’ mentions of the impact of environmental awareness on behavior change [13,14,15]. Lastly, the life perspective on convenience directly impacted behavioral intentions. Compared with the three factors influencing behavior, convenience had the strongest impact, followed by individual consciousness and environmental concern. Among these, convenience had the most immediate impact on daily life. Furthermore, the perceived damage had a greater impact and stronger incentive to make consumers aware of its environmental impact than autonomous consciousness.

Continuing from the previous conclusion, this study further explored areas for service improvement. It demonstrated that human thought patterns were not linear but complex, and the Kano model was employed to observe and define product attributes from multiple perspectives, revealing insights often overlooked in one-dimensional analysis. The Kano model deconstructed service convenience into three parts based on their qualities: service and portability, physical recycling points, and the cup return process. First, this study suggests that enhancing service convenience could further increase consumer willingness to use such services. Service and portability exhibited a one-dimensional quality, directly reflecting performance and correlating with changes in behavioral intention based on feelings of service satisfaction, which is also consistent with the results of past studies by scholars [38,39]. Second, the presence and improvement of physical recycling points can enhance convenience for consumers during returns. This aligned with the peak-end rule proposed by Kahneman [84], suggesting that consumers are profoundly influenced by their final experience, which may overshadow any negative aspects encountered during the service. Lastly, the cup return method significantly impacted the behavioral intention to start using returnable cups. The distinction between novices and experienced consumers lay in their participation in the service. Experienced consumers understood the convenience of the return process, resulting in a one-dimensional quality in the analysis. Novices, on the other hand, who had not experienced the service, still perceived the importance of return methods. In the past, the relevant processes and the current returnable cup service focused on attracting consumers, but the chain loop was not completely closed when the service ended the cycle. Despite potential variances in lifestyle preferences between Eastern and Western cultures, the ultimate determinant remains the consumer’s decision and choice. Therefore, in large cities with extremely high living convenience and population density, such as Taipei, Tokyo, and New York, it is important to form links through cooperation between industries and companies to achieve return convenience on the service’s back end. Convenience stores, chain fast food restaurants, and coffee shops everywhere can become universal return points, like convenience stores in Taiwan, which provide many different services, such as sending letters and picking up goods for online shopping. The benefits of such a business chain may be far more significant than those implemented independently by each company. For example, Loop, which is a worldwide returnable container company, uses similar methods to cooperate with various brands to implement systematic recycling. However, the influence of private enterprises often involves multiple vested interests, and the most effective approach lies in the intervention of governmental forces. When government subsidies intervene without compromising the profitability of enterprises, the entire cycle can be interconnected and chained. When government and corporate services are interconnected, enterprises can fulfill their social responsibilities, while the nation can serve as a global exemplar.

6. Conclusions

Sustainable progress indeed hinges on addressing both physical and psychological aspects in consumers’ lives, with this study revealing the fulfillment of both physical and psychological needs, which are both important to the consumers. Consumers with a higher level of environmental consciousness were willing to sacrifice some convenience to contribute to environmental protection. However, consumers with lower environmental awareness who met environmental needs may require passive satisfaction through service design. Therefore, this study suggests that while the majority of advertisements or public campaigns tend to inform consumers with a positive attitude, the actual processes of waste management and their environmental impacts are often overlooked by the average consumer. If the concrete impacts of disposable cups on the living environment could be effectively conveyed, it would further stimulate consumers’ sense of responsibility, thereby promoting the adoption of returnable cup systems. Furthermore, this study underscores the importance of the service experience, particularly the cup return process, in promoting returnable cups. It emphasizes the need to close the loop by ensuring a seamless and convenient return process, which is crucial for novice and experienced consumers. While many services focus on attracting consumers at the outset, this study underscores the significance of the endpoint in engaging the target audience.

The important characteristic of the returnable cups in this study lay in their integration into consumers’ daily lives through service provision, unlike returnable cups commonly utilized in events or catering, which are often constrained by activities and scope of use, and consumer convenience needs to be considered. This research helps the government to intervene in consumers’ passively acquired awareness through services at the publicity and education levels. It is also recommended that the government intervene to help private enterprises connect this huge service system and improve service convenience, thereby increasing consumers’ willingness to use the returnable cup service, hoping that this service can bring sustainable recycling and plastic reduction into people’s lives and contribute to the sustainable development of the environment.

7. Limitations and Future Studies

This study had several notable limitations that offer opportunities for future research and a more comprehensive understanding of sustainable beverage consumption practices. First, the focus on returnable cup services without considering the increasing trend of individuals bringing their own cups represents a significant gap. Exploring both returnable cup services and personal cup usage could provide valuable insights into the most effective sustainability solutions for the Taiwanese population. Second, this study highlights the popularity of returnable cup services in Europe, suggesting potential cultural differences in adoption rates and attitudes toward sustainability. Further exploration of these cultural factors could shed light on strategies to promote sustainable practices in Taiwan and other regions. Additionally, this study could benefit from including more social factors in its analysis. Factors such as social norms, peer influence, and cultural attitudes toward sustainability play crucial roles in shaping consumer behavior and warrant further investigation. By addressing these limitations and incorporating a broader range of factors into future research, we can gain a deeper understanding of sustainable beverage consumption practices and work toward the widespread adoption of environmentally friendly alternatives to disposable cups.