2.1. Research on Waste Separation Behavior
From the actor’s viewpoint, pro-environmental behavior is defined as behavior that is undertaken with the intention to benefit the environment [
16]. This perspective highlights individuals’ intent as the cause of pro-environmental behavior, suggesting that individuals intend to comply with environmental policy. Waste separation behavior is an environmentally significant behavior in the private sphere and one of several distinct types of pro-environmental behavior, such as non-activist behaviors in the public sphere [
17] and green practices in an organization [
18].
Waste separation is defined as a process by which waste is separated into different elements operated manually in the household [
2,
19]. The primary purpose of waste separation is to lessen environmental damage and achieve environmental sustainability [
20]. While most waste mitigation efforts are still required at the government and industry level, waste separation behavior at the household level is essential to reduce, recycle, and reuse waste [
21]. These benefits include reduced waste disposal and collection costs, reduced waste picker problems, resource conservation, prolonging the lifespans of landfills, and less carbon emission [
22].
Understanding the factors affecting individuals’ household waste separation behavior has been a research topic for many scholars in environmental literature. The literature offers various indicators that influence household waste separation behavior. These factors include the following: sociodemographic factors such as housing characteristics [
20], psychological factors, economic factors [
23], and political factors [
24,
25]. Specifically, most studies on psychological factors focus on perceived convenience and effort, state of knowledge and information, social norms, moral norms, attitude and environmental concern, habit, and system trust and community [
3]. Furthermore, previous research on waste separation behavior has largely been based on a different theoretical framework, such as the theory of planned behavior (TPB) [
26,
27], norm activation model (NAM) [
4,
28], attitude–behavior–context model (ABC) [
26,
29], and dual-factor theory (DFT) [
21].
2.2. Waste Separation Policy
With the rapid growth of the urban population, the growth of production and consumption, and improved living standards, waste generation has increased over time [
30]. Four options to tackle the issues of the rapid expansion of waste generation include the following: landfill, incineration, recovery, and waste recycling [
31]. Among these options, waste recycling has been regarded as the preferable option to tackle environmental issues [
1] because it can reduce the waste of resources and mitigate the adverse effects of waste on the environment [
32]. In fact, waste separation is a prerequisite of waste recycling [
33] and is still a popular strategy for waste management in many countries [
20].
For example, in South Korea, municipal waste disposal is divided into landfill, recycling, composting, and incineration [
34]. Most municipal wastes were reclaimed in local or metropolitan landfills, and very little was recycled in the 1980s and before. However, due to the difficulty of obtaining more land for landfill sites, finding ways to reduce waste generation and increase waste recycling was crucial. Since 1995, in an attempt to reduce the quantity of waste and increase the rate of recycling, the South Korean government has implemented solid waste management (SWM) legislation and initiatives, including a volume-based waste disposal fees (VBWF) system, a volume-based food waste disposal fees (VBFWF) system, a deposit refund system, extended producer responsibility (EPR), and bans on problematic plastic items and packaging, leading to waste reduction since the early 1990s [
6]. Since 1996, the amount of waste from Seoul going to landfill has fallen by almost 90%. In recent years, nearly 70% of Seoul’s household general waste has been recycled, with less than 10% going to landfill and the rest being processed at Seoul’s resource recovery facilities [
35].
Recent years have witnessed the appearance of mandatory environment policy as a crucial factor affecting individuals’ waste separation behavior [
4,
36,
37,
38,
39,
40]. Hence, several governments encourage people to engage in waste separation behavior [
41]. However, with the rising government regulation around the globe, household waste separation is no longer merely a voluntary behavior driven by personal attitudes. Despite municipal governments’ commitment to tackling the waste problem, only 15% of waste is recycled around the globe [
42]. To increase waste recovery from urban waste, better household waste separation is needed, and active sustainable waste management has to be taken at the individual level [
2,
21,
27,
28].
However, while the literature on household waste separation behavior abounds, few studies concern the factors affecting individuals’ compliance with the waste separation policy. Given the growth of mandatory waste separation policy, studying the determinants of compliance with waste separation policy is worthwhile.
2.3. Compliance with Waste Separation Policy
Given the similarity between municipal environmental policy violations and criminal behavior in social settings, the theoretical perspectives developed in criminology literature could be adopted as the foundations for waste separation behavior research, including, but not limited to, rational choice theory [
12,
13] and deterrence theory [
14,
15].
Two relevant theories, i.e., rational choice theory and deterrence theory, will be integrated to increase our knowledge of waste separation policy compliance. To the best knowledge, prior research has yet to use both theories in a single study on waste separation behavior.
2.3.1. Perceived Benefit and Perceived Effectiveness of Waste Separation Behavior
Rational choice theory, one of the criminological theories, is essentially a subjective expected utility theory, suggesting that an individual’s decision calculus to offend is based on the perceived or personal expectations of cost and benefit [
43]. Thus, individuals are sensitive to the consequences of their behaviors and make reasoned decisions based on the cost–benefit analysis of the intended behaviors [
12].
In the context of waste separation, individuals only participate in waste separation if the expected utility of waste separation exceeds that of conventional waste disposal [
23]. This model identifies two considerations in an individual’s decision to adopt waste separation behavior in response to cost–benefit analysis, i.e., perceived benefit of waste separation behavior and perceived effectiveness of waste separation behavior. Perceived benefit (PB) refers to individuals’ personal belief in the positive impact of waste separation behavior on the environment [
44]. Previous studies suggest that an individual aware of the benefit of waste separation behavior will engage in it [
10,
45]. Perceived effectiveness (PE) refers to individuals’ perceptions about the effectiveness of their ecological efforts in reducing environmental harms through waste separation behavior [
46]. If an individual perceives more effective external motivation, the intention to perform a certain behavior will become stronger. Previous studies show that if an individual has a higher level of awareness of the positive consequences of waste separation behavior, the intention to perform such behavior would be higher [
7,
47]. Thus, higher perceived benefit and perceived effectiveness will likely lead to greater intention to comply with the waste separation policy. This study proposes the following research hypotheses:
Hypothesis (H1). Perceived benefit of waste separation behavior positively influences intention to comply with the waste separation policy.
Hypothesis (H2). Perceived effectiveness of waste separation behavior positively influences intention to comply with the waste separation policy.
2.3.2. Perceived Deterrent Severity and Perceived Deterrent Certainty
Deterrence theory argues that criminal behavior results from a rational calculation of costs and benefits [
12,
48]. When individuals perceive that the costs of deviant behaviors outweigh the benefits, they will choose to comply with the law rather than engage in crime. The theory proposes that deterrence against certain deviant behaviors can prevent individuals from engaging in violations, suggesting the effect of formal sanctions in motivating individuals to follow public policies [
4].
The theory assumes that individuals calculate the disutility of sanctions and try to minimize it by considering perceived deterrent severity and certainty [
11,
49]. Perceived deterrent severity (DS) refers to the deterrence’s harshness or the price to be paid for the crime [
4,
38]. Perceived deterrent certainty (DC) refers to the possibility that the deviant behavior will be discovered and a penalty imposed [
4,
38]. Individuals are expected to comply with public policies as the level of deterrent severity and certainty increases [
49].
In the context of waste separation, deviant behaviors include inadequate separation, wrong location or container placement, and midnight dumping [
4]. The corresponding deterrence includes fines, detention, and imprisonment. In this case, the benefits of not complying with waste separation policy are only time-saving and reducing daily chores. In contrast, the cost of violating the waste separation policy is much higher than the benefit. For example, illegal waste disposal in Seoul could result in a fine of up to KRW 300,000 (or approximately USD 250). Moreover, a surveillance camera on a power pole monitors illegal waste dumping. This deterrent effect will increase compliance with the waste separation policy. Thus, higher perceived deterrent severity and perceived deterrent certainty will likely lead to greater intention to comply with the waste separation policy. This study proposes the following research hypotheses:
Hypothesis (H3). Perceived deterrent severity positively influences intention to comply with the waste separation policy.
Hypothesis (H4). Perceived deterrent certainty positively influences intention to comply with the waste separation policy.
2.3.3. Antecedents of Waste Separation Behavior
The theory of planned behavior assumes that individuals’ behaviors are influenced by intentions [
50]. In the context of waste separation, previous studies provided empirical evidence that the intention of waste separation behavior forces waste separation behavior [
19,
51]. Thus, this study proposes the following research hypotheses:
Hypothesis (H5). Intention to comply with waste separation policy positively influences waste separation behavior (i.e., compliance behavior).
This study also included moral belief as a control variable positively affecting waste separation behavior. Moral belief is based on the perspective that what individuals regard as morally right or wrong affects their behavior [
48]. In our context, moral belief refers to the degree to which individuals perceive a violation of the waste separation policy as morally unacceptable [
27,
52]. Previous studies indicate that moral belief is crucial to waste separation behavior [
53,
54].
Collectively, the literature review led us to propose the research model in
Figure 1.