Direct Expression or Indirect Transmission? An Empirical Research on the Impacts of Explicit and Implicit Appeals in Green Advertising

Abstract

Green advertising has been shown to motivate consumers to engage in green consumption behavior. However, little is known about how resource scarcity affects the efficacy of explicit and implicit appeals in green advertising. To address it, the present research investigates the differential impacts of ecological resource scarcity (vs. abundant) and personal resource scarcity (vs. abundant) on consumers’ evaluations of explicit and implicit green advertising appeals. We proposed that the relationship between resource scarcity and green advertising appeals are mediated by consumers’ perception of green products’ effectiveness. We conducted two experimental designs to examine our hypothesis. The findings show that when consumers perceive ecological resource scarcity (vs. abundant), companies that emphasize the environmental attributes of green products (e.g., explicit appeals) are more effective in conveying green messages (study 1). Conversely, when consumers experience personal resource scarcity (vs. abundant), employing the approach of green understatement (e.g., implicit appeals) to highlight the performance advantages of green products would result in favorable consequences (study 2). Furthermore, this research reveals the critical role of perceived green products’ effectiveness in improving consumers’ attitude and purchase intention (studies 1 and 2). Resource scarcity will not always decrease consumers’ pro-environmental intention. Interestingly, ecological resource scarcity and personal resource scarcity lead to opposite preferences for green advertising appeals. These findings contribute to the literature on resource scarcity in the domain of green consumption, as well as having significant practical implications for advertisers and marketers in conveying effective information for green product promotion.

1. Introduction

With the increasing intensification of climate change, water shortages, and biodiversity destruction, sustainability has emerged as a critical issue for governments, corporations, and societies worldwide. Many corporations have realized the growing trend of green consumption and have made initiatives to incorporate their environmental efforts into their business. However, because of individual and family conventional consumption values, implementing green consumption in the market may be more challenging. Despite being surrounded by numerous green products, consumers’ acceptance of green consumption varies greatly [1]. Thus, it is imperative to explore new ways to encourage consumers to develop habits of sustainable consumption.

Green advertising as a promotional strategy emphasizing the environmental attributes of products and services has gained considerable scholarly interest in terms of stimulating green consumption [2,3]. On the one hand, green advertising is critical for promoting the attributes of environmentally friendly products, minimizing promotional uncertainty, and better influencing consumers’ purchase decisions [4]. On the other hand, consumers are skeptical of green advertising claims, especially when advertisers employ vague or even deceptive environmental appeals [5]. Businesses have to develop more persuasive communication tactics to attract consumers to purchase green products. Drawing on green advertising literature, the present research identifies two distinct green advertising appeals. Explicit appeals are frequent terms that introduce the products’ environmental aspects more directly. For example, ECOVER, a laundry detergent brand, declares unequivocally that its products are environmentally friendly because its major components are derived from natural plants. Implicit appeals are another typical mode of transmission that reduce the emphasis of ecological aspects by highlighting functional information. Kao, for example, has concentrated on product performance-related features such as decontamination ability, antibacterial capability, and cost or time savings.

In the realm of green marketing, both explicit and implicit green appeals are common communication tactics to inspire customers. In general, corporations frequently utilize eco-labels or green imagery in green advertising appeals to emphasize the environmental attributes of their products [6]. Because specific information is considered more reliable and memorable than others, consumers prefer to access explicit messages presented by advertisements [7]. Prior research has documented a positive relationship between green argument strength and consumer response, with strong green arguments eliciting better consumer perceptions of credibility than weak ones [8,9]. Kronord et al. (2012) also found that green appeals that adopt assertive language are more effective with consumers who perceive the environmental issues as important [10]; that is, that explicit environmental appeals are more persuasive than implicit appeals. However, other studies documented that this strategy may backfire since consumers believe that the corporation devoted more resources away from product quality when the green enhancement is intended [11]. Implicit green advertising appeals that emphasize the functional features of green products may be more effective when consumers are more concerned with product performance than green expectations [12]. As a result, it remains uncertain which advertising appeal would more successfully convince consumers to engage in sustainable consumption, and which factors impact the persuasive effect of explicit and implicit green appeal.

To fill this gap, the present research examines the effects of resource scarcity on green advertising appeals. Resource scarcity is a pervasive and ubiquitous social phenomenon in human life [13]. Scarcity is associated with negative effects when human beings have greater wants than resources [14]. This psychological state might cause a generalized mindset that influences subsequent consumption decisions in unrelated circumstances [15,16,17]. Many researchers in the resource scarcity literature have assumed that people exposed to resource scarcity pay more attention to scarcity-related concerns and are also more motivated to improve their own welfare, leading to more selfish behavior in pro-social domains [13]. However, other studies have found that reminders of resource scarcity may lead to certain contrary behavior [18]. Drawing on these previous findings, the current research proposed that consumer responses to explicit and implicit green advertising appeals may be influenced by their perception of resource scarcity.

According to Construal Level Theory (CLT), psychological distance influences how individuals represent things or experiences [19]. Specifically, ecological resources (e.g., forests, oil, and coal) are more typically associated with other people in society; consumers may psychologically consider the ecological resource scarcity as something far away from them. Conversely, personal resources (e.g., time, money, and energy) are more commonly associated with self-benefit; consumers may regard the personal resource scarcity as something near to them. Thus, ecological resource scarcity is mostly associated with high construal level, whereas personal resource scarcity is closely connected with low construal level. Prior research has examined the relationship between green advertising appeals and construal levels for luxury and sustainable brands [20]. Given such inferences, we proposed two boundary conditions for these effects: one based on consumer perception of ecological resource scarcity, and the other on consumer perception of personal resource scarcity. Moreover, green product effectiveness is one driving factor for green consumption. Consumers are hesitant to purchase green products because they perceive green products as less effective than their conventional counterparts [21,22]. Thus, it is important to understand how to improve consumer perception of green product effectiveness through the transmission of green advertising appeals to individuals experiencing resource scarcity.

Accordingly, the present research seeks to examine the differential effects of ecological and personal resource scarcity on consumers’ evaluations of explicit and implicit green advertising appeals. We proposed that construal level theory and value congruity can explain these results; that is, consumers’ perception of resource scarcity will influence how they evaluate green advertising appeals. Specifically, increased ecological resource scarcity will elicit high construal level and encourage consumers’ concern for others, prompting them to recognize the relevance of environmental and social repercussions. As a result, explicit green appeals with direct sustainable features will perform better than implicit green appeals. However, growing personal resource scarcity will elicit low construal level and stimulate individuals’ self-focus, urging them to rely more on the performance of green products. In this case, implicit green appeals with indirect environmental attributes will outperform explicit green appeals. We further proposed that these interaction effects are mediated by perceived green product effectiveness. If supported, these findings will not only contribute to a better understanding of scarcity-mindsets in the green marketing literature, but also provide a practical contribution for marketers in matching relevant green advertisements to scarcity-mindset consumers.

2. Literature Review and Hypothesis

2.1. Green Advertising Appeals

Green advertising was defined as communication strategies that emphasize the environmental attributes of products and services, which can satisfy the expectations of environmentalist [23,24]. Prior study found that green advertisements with more convincing arguments can encourage consumers to evaluate these green messages more positively [25].

Researchers across diverse fields have compared the influence of various advertising appeals on sustainable consumption, such as abstract and concrete appeals, other-benefit and self-benefit signals, or gain and loss message framings [26,27,28]. After collating the literature of green advertising, we found that both the content and expression of advertisements can significantly affect consumers’ attitudes and behaviors toward green consumption. In practice, there always exists a lay theory in green consumption that consumers are likely to associate sustainability with low product performance [21]. Thus, how consumers perceive the prominence of a product’s environmental characteristics through advertisements might vary greatly. Companies and marketers who provide environmentally friendly products or services are eager to figure out the effectiveness of emphasizing sustainability in green advertising appeals [29].

To solve this problem, the current article focuses on two green advertising strategies: explicit appeals and implicit appeals. The difference between explicit green appeals and implicit green appeals is whether the environmental attributes are communicated directly or indirectly [18]. Specifically, conspicuous ecolabels and prominent phrases used in explicit green appeals enable consumers to conclude that the product includes obvious sustainable advantages. By contrast, implicit appeals convey the traits of environmental more vaguely or indirectly, focusing instead on more utilitarian features.

Although previous research has found that consumers respond positively to assertive appeals in a variety of environmental circumstances [10], the sustainability or environmental advantage entails a liability that restricts the quality inference of green products [22]. Taken together, prior studies on green advertising appeals cannot definitively show which method of transmitting sustainable information may most successfully influence the evaluation of green products.

Past research has shown that consumers are inclined to draw ambivalent conclusions or even act in contradictory ways in responses to the same information [30]. The current study investigates the relative effectiveness of green advertising appeals (e.g., explicit vs. implicit) on consumers’ evaluations through a new perspective: the scarcity mindset. Our view is that advertisers should learn how to structure their message based on how consumers’ psychological processes respond to these green communication strategies.

2.2. The Scarcity Mindset

Scarcity is a “mindset” that involves “having less” [31]. This subjective sensation might drain individuals’ mental resources and make them less concerned with other duties. Researchers have explored many different types of resource scarcity, including money [32], time [33,34], products [35], and ecological [18] Scarcity, as a pervasive phenomenon, plays an important role in guiding individuals’ emotions and behavior.

Mullainathan and Shafir (2013) indicate that scarcity increases cognitive load by focusing on the shortage of resources, but they did not compare the psychological consequences induced by different scarcity types [14]. Our review of the literature suggests that consumers’ responses to various scarcity circumstances may be guided by the “other-focused” or “self-focused” attitude. Ecological resource scarcity in particular refers to a shortage of sufficient quantities of natural resources (e.g., oils, water, and forests) to fulfill humankind’s expanding demand [36]. As the world population grows and consumption rises, stemming from economic development, ecological resource scarcity is emerging as an imminent social concern on a global scale.

Another type of scarcity is related to individuals’ owns wants and needs. Everyone lacks something in their daily lives, such as money, time, or energy [37]. Personal resource scarcity can be regarded as the source that limits their intended consumption. Personal resource scarcity, like ecological resource scarcity, can influence individuals’ decision-making. For example, once personal resource scarcity cognitions are aroused, consumers are more motivated to pursue their own benefits [13]. The most notable distinction between ecological and personal resource scarcity is that the latter is more intimately tied to individuals’ own interests, implying that consumers who encountered personal resource scarcity would alter their cognitions to obtain self-benefits.

We can explain our argument from the perspective of construal level theory (CLT). According to CLT, the psychological distance between individuals and objects influences how they feel and think about them [26,38]. When individuals perceive an item to be psychologically distance, they tend to think of the object’s attributes in a more abstract manner, whereas when they consider an object to be psychologically close, they think in a more concrete manner [19]. Based on this notion, we anticipate that consumers would psychologically consider ecological resource scarcity as being far removed from their own concerns. Conversely, consumers may regard personal resource scarcity to be intimately related to them, owing to the emphasis on their own interests. Thus, the incentives to encourage individuals to adopt sustainable choices may vary depending on how different forms of resources scarcity are perceived.

Despite the plethora of research which has separately examined how scarcity mindsets influence consumers’ behaviors, scant attention has focused on comparing the consequences of ecological resource scarcity (vs. abundant) and personal resource scarcity (vs. abundant) in the green consumption arena. Therefore, the present study attempts to examine the varying evaluations of green advertising appeals (explicit vs. implicit) under the two scarcity conditions (ecological vs. personal).

2.3. The Moderating Role of Ecological Resource Scarcity

Consumers are becoming increasingly aware of environment issues. Environmentally friendly behaviors are closely related to a society that conserves resources and future sustainable growth. The welfare of pro-environmental behaviors are external to the individual and provide benefits in the future [39]. Previous research has established that reminding people of ecological resource scarcity would improve environment friendly behavior for future-oriented individuals [18]. Individuals share ecological resources with others in the society, and the severity of ecological resource scarcity would also draw consumers’ attention to the advantages of others or groups. Sachdev and Zhao (2019) found that individuals who perceived a scarcity of natural resource (e.g., water) behave with more pro-environmental motivations [40]. Therefore, we predict that perceived ecological resource scarcity (vs. abundant) will stimulate more concern about other people in society, influencing consumer evaluations about the message of green products.

As we discussed before, when individuals are reminded of ecological resource scarcity, they will enact high construal level and an abstract mindset, focus on preserving or protecting environmental resources, and subsequently exhibit a greater interest in sustainable consumption. They may prefer to invest in improving the lives of others or societal advantages through pro-environmental measures. Conversely, people may not sacrifice their immediate benefits to obtain delayed rewards in the future if they receive messages about ecological resource abundance. Thus, consumers are willing to choose and use the products that satisfy their own wants and needs. For this reason, consumers who sense ecological resource scarcity will have greenness expectations, which means that explicit green appeals are more likely to improve their attitudes and purchase intentions toward sustainable products. In contrast, under ecological resource abundance conditions, consumers may prefer the traditional function of green products to meet their immediate requirements. Thus, implicit green appeals may more effectively improve their green attitudes and purchase intentions. Therefore, we hypothesize the following:

Hypothesis 1 (H1).

There is a relationship between ecological resource scarcity and green advertising appeals on green consumption intention. (a) When individuals perceive high (vs. low) level ecological resource scarcity, the explicit (vs. implicit) green appeals will lead to higher advertising attitudes and purchase intentions. (b) When individuals perceive low (vs. high) level ecological resource scarcity, the implicit (vs. explicit) green appeals will lead to higher advertising attitudes and purchase intentions.

2.4. The Moderating Role of Personal Resource Scarcity

Various related findings have offered convergent evidence that scarcity activated in the personal domains (e.g., money, time, or energy) might promote selfish behaviors. Roux et al. (2015) posited that reminding consumers of personal resource deficiency can stimulate a competitive orientation, which guides consumers to behave more selfishly in a subsequent task, like retaining money for themselves instead of allocating to fellows in the game [13]. When consumers experience scarcity in one domain (e.g., financial deprivation), they become more likely to engage in immoral behaviors to mitigate the negative impact of scarcity in subsequent decisions [41]. Even though there is no actual scarcity, just activating the cognitions associated with losing money can stimulate consumers’ desire to gain self-benefit regardless of others [42]. These findings are consistent with previous study on time constraints [34] and food shortages [43].

Considering this argument, consumers regard personal resources (e.g., money, time, or energy) as more intimately related to them. Low construal level and concrete mindset would be activated when scarcity conditions are psychologically close to individuals. They tend to prompt self-focused behaviors while suppressing other-focused intentions. By contrast, consumers will have more slack space to adjust for momentary failures of self-control when they perceive their personal resources to be abundant. Sufficient resources can help them to get rid of the trouble of trade-offs and become more willing to help others or behave in an environmentally friendly manner to promote well-being. In this paper, we proposed that when consumers experience personal resource scarcity, implicit green appeals that transmit pro-social benefits in an indirect way or highlight conventional functions (e.g., good quality, reduced cost, improved health) may effectively improve their attitudes and purchase intentions toward green consumption. In contrast, when consumers have substantial personal resources, they may favor green product features with prominent environmental characteristics. At this time, explicit green appeals will perform better in improving consumer attitudes and purchase intentions toward sustainable products. Therefore, we hypothesize the following:

Hypothesis 2 (H2).

There is a relationship between personal resource scarcity and green advertising appeals on green consumption intention. (a) When individuals perceive high (vs. low) level personal resource scarcity, the implicit (vs. explicit) green appeals will lead to higher advertising attitudes and purchase intentions. (b) When individuals perceive low (vs. high) level personal resource scarcity, the explicit (vs. implicit) green appeals will lead to higher advertising attitudes and purchase intentions.

2.5. The Mediating Role of Perceived Green Product Effectiveness

Product effectiveness refers to the product achieving what it purports to do. Consumers always hold ambivalent attitudes towards the effectiveness of green products. Lin and Chang (2012) indicated that consumers generally evaluate green or environmentally friendly products as less effective than regular products due to the sustainability liability. That means, sustainability may not always be an asset in the promotion of green consumption behaviors, and consumers easily infer that green product with superior sustainable attributes would be relatively inferior in other dimensions [22].

External cues can be used to make inferences about the effectiveness of green products; in particular, congruity of messaging can enhance the experience of individuals, which heightens their evaluative reactions in subsequent decisions. [44]. According to a previous study, matching the appropriate information can improve the perception of green product effectiveness, leading to positive brand attitudes [45]. Thus, it is essential to find out how to express sustainable information to improve the evaluation of green products. The current study argues that the relationship between green messages and scarcity mindsets can increase the evaluation of perceived green product effectiveness, positively affecting consumers’ attitudes and purchase intentions.

Specifically, explicit (vs. implicit) green advertising appeals are particularly effective in improving the perception of green product effectiveness for individuals who are experiencing ecological resource scarcity (vs. abundant). At the same time, implicit (vs. explicit) advertising appeals are performing better in increasing the perception of green product effectiveness for consumers who are restricted in personal resource scarcity (vs. abundant). Therefore, we predict that an appropriate match between resource scarcity mindsets and green advertising appeals (explicit vs. implicit) can improve consumers’ perceptions of the effectiveness of green products, thus increasing their attitudes and purchase intentions toward green consumption. We hypothesize the following:

Hypothesis 3 (H3).

(a) Perceived green product effectiveness mediates the impact of relationship between ecological resource scarcity and green advertising appeals on their advertising attitudes and purchase intentions. (b) Perceived green product effectiveness mediates the impact of relationship between personal resource scarcity and green advertising appeals on their advertising attitudes and purchase intentions.

We conducted two experimental studies to examine our hypotheses. Study 1 sought to identify the relationship between green advertising appeals (explicit vs. implicit) and consumers’ perception of ecological resource scarcity (vs. abundant). In study 2, we introduce the concept of personal resource scarcity (vs. abundant) and examine its role in influencing the persuasiveness of green advertising appeals (explicit vs. implicit). We confirmed the role of perceived green product effectiveness as mechanisms both in study 1 and 2. The overall conceptual framework is depicted in Figure 1.

3. Study 1

Study 1 aims to examine the impact of the relationship between green advertising appeals and ecological resource scarcity on consumers’ attitudes and purchase intentions (Hypothesis 1). Moreover, we also test the mediating role of perceived green product effectiveness underlying the interaction effect (Hypothesis 3a).

3.1. Design and Participants

Study 1 used a 2 (green advertising appeal: explicit vs. implicit) × 2 (ecological resource: scarcity vs. abundant) between-subjects experiment. We recruited 201 participants from Credamo, a data collection platform in China, and they participated in this study for monetary compensation [46,47]. Five participants gave all the same answers or did not pass the attention check question. The final sample thus comprised 196 valid respondents (65.8% female; M age = 29).

Table 1. Sociodemographic information.

Studies	Study 1		Study 2
Sample size	196		229
	Frequency	Percent (%)	Frequency	Percent (%)
Gender
Male	67	34.18	81	35.37
Female	129	65.82	148	64.63
Age
20 and below	11	5.61	35	15.28
21–30	122	62.24	138	60.26
31–40	49	25	42	18.34
41 and above	14	7.15	14	6.12
Education
High school and below high school graduate	21	10.71	22	9.61
Bachelor’ degree	140	71.43	163	71.18
Postgraduate	35	17.86	44	19.21
Occupation
Student	-	-	99	43.23
Nonstudent	-	-	130	56.77

provides the sociodemographic information. Among the participants, 5.61% were below 20 years old, 62.24% were between 21 to 30 years old, 25% were 31 to 40 years old, and 7.15% were over 41 years old. All participants were randomly assigned to one of the four experimental conditions.

3.2. Procedure and Measures

Participants first read a scenario about water resource-scarcity (vs. resource-saving) in China. The two reading materials were sourced from real information and were approximately the same in length. Specifically, the content in the scarcity group is mainly about the shortage of water resources. For example, emphasizing the uneven distribution of water resources, the growing disparity between availability and demand for water resources, and the substantial wastage of water resources. In contrast, the content in the control group is related to water resource conservation measures. For example, highlighting how to fully utilize water resources, encouraging the building of sponge cities, and boosting the utilization of unconventional water resources. After the reading task, participants indicated their scarcity extent on a two-item scale [32].

Subsequently, participants were asked to imagine they intended to purchase a laundry detergent and viewed green advertisements using explicit or implicit appeals. We developed a fictitious brand to eliminate the effects of prior brand knowledge. In each condition, we held the text content constant, stating “the ingredients of laundry detergent are mild and safe, ensuring great cleaning experiences by disintegrating varieties of stains easily.” To manipulate explicit green appeals, we put an enlarged ecolabel beneath the main text to make it prominent in the advertisement. To lessen the emphasis on environmentalism, the ecolabel appears at the bottom of the ad and in a small size for implicit green appeals. To confirm our manipulations, we employed a bipolar scale with four items: “The green message in the advertisement is implicit (e.g., subtle, indirect, implicit, and imprecise) or explicit (e.g., explicit, direct, assertive, and precise)” to ensure our manipulations [12,48].

Participants then evaluated their advertising attitudes on a 3-item scale [49], indicated their product purchase intention on a 3-item scale [50], and rated their perceived green product effectiveness on a 4-item scale [44]. Finally, participants responded to some demographic questions. All items were measured on a 7-point Likert scale and summarized in

Table A1. Variables and measurement scales used in Studies 1 and 2.

Reliability
Variables	Measures	Study 1	Study 2
Scarcity Manipulation (Tully et al., 2015) [32]	I think about the current ecological/personal resource scarcity situation while the reading task; My feeling about the current ecological/personal resource scarcity is obviously	α = 0.92	α = 0.92
Appeals Manipulation (Gu et al., 2020) [18]	The green message in the advertisement is (1 = subtle/indirect/implicit/imprecise; 7 = assertive/direct/explicit /precise)	α = 0.88	α = 0.93
Ad Attitude (Mackenzie & Lutz, 1989) [49]	I feel this advertisement is good; I feel pleasant with this advertisement; I feel this advertisement is favorable (1 = totally disagree; 7 = totally agree)	α = 0.90	α = 0.89
Purchase Intention (Dodds et al., 1991) [50]	My willingness to buy the product is very high; The probability that I would consider buying the product is very high; The likelihood of purchasing this product is very high (1 = totally disagree; 7 = totally agree)	α = 0.91	α = 0.93
Perceived Green Product Effectiveness (Chen & Chiu, 2016) [45]	The laundry detergent/notebook has good cleaning results/ has good writing results; The laundry detergent/notebook is an effective product; The laundry detergent/notebook has good quality; A laundry detergent/notebook that is environmentally friendly is rarely effective (R) (1 = totally disagree; 7 = totally agree)	α = 0.84	α = 0.80

.

3.3. Results and Discussion

Manipulation checks: A 2 (green advertising strategy: explicit vs. implicit) × 2 (ecological resource: scarcity vs. abundant) analysis of variance (ANOVA) showed that the extent of scarcity perceived in the high condition (M_scarcity = 6.34, SD = 0.60) was significantly higher than that in the low condition (M_abundant = 4.22, SD = 1.67; F(1, 194) = 139.79, p < 0.001, η² = 0.42). In addition, we found that our manipulations of explicit (M_explicit = 5.69, SD = 1.08) and implicit appeals (M_implicit = 4.94, SD = 1.50) were also successful (F(1, 194) = 16.29, p < 0.001, η² = 0.08).

Advertising attitude (Ad attitude): A 2 × 2 ANOVA on advertising attitude (α = 0.90) showed that the interplay effect between green advertising appeals and ecological resource scarcity was significant (F(1, 192) = 15.70, p < 0.001, η² = 0.08; see Figure 2). Neither the main effect of green advertising appeals nor resource scarcity were significant (p > 0.33). Specifically, participants in the abundant condition demonstrate higher advertising attitudes to implicit appeals than explicit appeals (M_implicit = 5.55, SD = 0.95, M_explicit = 5.03, SD = 1.22; F(1, 96) = 5.57, p = 0.02, η² = 0.06). While participants in the scarcity condition show higher advertising attitudes to explicit appeals than implicit appeals (M_explicit = 5.50, SD = 0.97; M_implicit = 4.77, SD = 1.25; F(1, 96) = 10.45, p = 0.002, η² = 0.10).

Purchase intention: Next, we ran a 2× 2 ANOVA on purchase intention (α = 0.91) to reveal the significant interplay effect between green advertising appeal and ecological resource scarcity (F(1, 192) = 10.80, p = 0.001, η²= 0.05; see Figure 3). Neither the main effect of green advertising appeals nor resource scarcity were significant (p > 0.66). Specifically, participants in the abundant condition indicate higher advertising attitudes to implicit appeals than explicit appeals (M_implicit = 5.65, SD = 0.87; M_explicit = 5.10, SD = 1.35; F(1, 96) = 5.59, p = 0.02, η² = 0.06), while participants in the scarcity condition indicate higher advertising attitudes to explicit appeals than implicit appeals (M_explicit = 5.57, SD = 0.88; M_implicit = 5.03, SD = 1.38; F(1, 96) = 5.21, p = 0.025, η² = 0.05).

Mediation analysis: We conducted bootstrapping analyses with 5000 samples to test the interactive effect on advertising attitude through perceived green product effectiveness (PROCESS model 8) [51]. With Ad attitude as the dependent variable, we examined the interactive effect of green advertising (implicit appeal = 1, explicit appeal = 2) and ecological resource scarcity (low level = 1, high level = 2) with perceived green product effectiveness as the mediator. A 95% confidence interval (CI) for the indirect effect was significant and excluded zero (β = 0.76, 95% CI: [0.32, 1.25]), and the interaction effect was also significant and excluded zero (β = 0.49, 95% CI: [0.03, 0.96]). That is, perceived green product effectiveness partially mediated the interaction effects of green advertising appeals and resource scarcity on advertising attitude (see Figure 4a).

The mediating effect of perceived green product effectiveness on purchase intention was analyzed in the same way. A 95% confidence interval (CI) for the indirect effect was significant and excluded zero (β = 0.90, 95% CI: [0.40, 1.45]); however, the interaction effect was not significant and included zero (β = 0.18, 95% CI: [−0.23, 0.59]). That is, perceived green product effectiveness fully mediated the interaction effects of green advertising appeal and resource scarcity on purchase intention (see Figure 4b).

Across study 1, we found that consumers’ attitudes and purchase intentions toward explicit (vs. implicit) green advertising appeals are higher when they perceive high-level (vs. low-level) ecological resource scarcity, consistent with Hypothesis 1. That is, reminding consumers of ecological resource scarcity will elicit their high construal level, leading them to contemplate the global ecological environment’s future. Explicit green advertising appeals that are aligned with prominent pro-environmental attributes will increase consumers’ attitudes and purchase intentions for green products. Conversely, when consumer perceive low-level of ecological resource scarcity, implicit green advertising appeals with understatements of green products’ environmental features will perform better. Study 1 further offers evidence that consumers’ perceived green products effectiveness mediates the relationship between green advertising appeals and the extent of ecological resources scarcity, supporting Hypothesis 3a.

4. Study 2

Study 2 was designed to further examine the relationship between personal resource scarcity and green advertising appeals (Hypothesis 2). Consumers use personal resources (e.g., current income or wealth) to maintain their own and their family’s normal life [52]. In contrast to scarcity of ecological resources, consumers may regard personal resources as something closely related to their own interests, and so focus on self-related constraints concerns. Following this logic, we predict that when consumers are confronted with personal resource scarcity, they would perform low construal level and prefer to obtain self-benefit, which will lead to less sustainable consumption behavior.

4.1. Design and Participants

Study 2 used a 2 (green advertising appeal: explicit vs. implicit) × 2 (personal resource: scarcity vs. abundant) between-subjects experiment. We recruited 245 participants from Credamo, sixteen of which gave identical answers or failed to pass the attention check question. The final sample thus comprised 229 valid respondents (64.6% female; M age = 27). The sociodemographic information can be found in Table 1. Among the participants, 15.28% were below 20 years old, 60.26% were between 21 to 30 years old, 18.34% were 31 to 40 years old, and 6.12% were over 41 years old. All participants were randomly assigned to one of the four experimental conditions.

4.2. Procedure and Measures

Firstly, to manipulate personal resource scarcity, we ask participants to complete an episodic recall task [13]. Specifically, all participants should describe three episodes in detail about “they didn’t have enough of something (e.g., money, time, or energy)” or “they did have enough of something (e.g., money, time, or energy)”, explaining what was lacking or abundant and what they experienced. We then used the scale adapted from study 1 to measure their scarcity extent.

Next, all participants were instructed to imagine they were going to purchase a notebook. We designed two kinds of green advertisements, making either environmental-related (explicit) or functional-related (implicit) attributes more prominent [12]. In the explicit green appeals condition, respondents were told the superior environmental attributes of the notebook in a more directly way; specifically, at the bottom of the advertisement, there was a subheading that detailed the product’s nonenvironmental characteristics in reduced font size. For the implicit green appeals, we reversed the order to underline the product’s functional features and downplay the pro-environmental aspects. We also measured the manipulations whether they have the desired effect or not. Finally, we collect advertising attitude and purchase intention, as well as perceived green product effectiveness, and participants reported their demographic questions. The structure and content of the questionnaires in study 2 were similar to those in study 1.

4.3. Results and Discussion

Manipulation checks: Participants report higher scarcity extent in the scarcity condition (M_scarcity = 5.75, SD = 1.09) than the abundant group (M_abundant = 3.59, SD = 1.53; F(1, 227) = 149.49, p < 0.001, η² = 0.40). Additionally, participants perceived that the explicit appeals transform green messages more directly than the implicit appeals (M_explicit = 6.15, SD = 0.76, M_implicit = 3.93, SD = 1.65; F(1, 227) = 171.74, p < 0.001, η² = 0.43).

Advertising attitude. A 2 × 2 ANOVA showed a significant interaction between green advertising appeals and personal resource scarcity on advertising attitude (α = 0.89), (F(1, 225) = 17.84, p < 0.001, η² = 0.07; see Figure 5). Neither the main effect of green advertising appeals nor resource scarcity was significant (p > 0.48). Specifically, participants in the scarcity condition indicate higher advertising attitudes to implicit appeals than explicit appeals (M_implicit = 5.15, SD = 0.84; M_explicit = 4.62, SD = 1.16; F(1, 109) = 7.49, p = 0.007, η² = 0.07), while participants in the abundant condition indicate higher advertising attitudes to explicit appeals than implicit appeals (M_explicit = 5.14, SD = 1.10, M_implicit = 4.42, SD = 1.29; F(1, 116) = 10.54, p = 0.002, η² = 0.08).

Purchase intention: Next, we ran a 2 × 2 ANOVA to reveal the interplay effect between green advertising appeal and personal resource scarcity on purchase intention (α = 0.93), (F(1, 125) = 10.20, p = 0.002, η² = 0.04; see Figure 6). Neither the main effect of green advertising appeals nor resource scarcity were significant (p > 0.50). Specifically, participants in the scarcity condition indicate higher advertising attitudes to implicit appeals than explicit appeals (M_implicit = 5.33, SD = 1.09, M_explicit = 4.83, SD = 1.35); (F(1, 109) = 4.47, p = 0.037, η² = 0.04), while participants in the abundant condition indicate higher advertising attitudes to explicit appeals than implicit appeals (M_explicit = 5.27, SD = 1.31, SD = 0.88, M_implicit = 4.65, SD = 1.49; F(1, 116) = 5.82, p = 0.017, η² = 0.05).

Mediation analysis: We also conducted a mediating analysis (PROCESS model 8) to test the interactive effect on advertising attitude through perceived green product effectiveness. A 95% confidence interval (CI) for the indirect effect was significant and excluded zero (β = −0.61, 95% CI: [−1.05, −0.17]), and the interaction effect was also significant and excluded zero (β = −0.64, 95% CI: [−1.05, −0.24]). That is, perceived green product effectiveness partially mediated the interaction effects of advertisement appeals and resource scarcity on advertising attitudes (see Figure 7a).

The mediating effect of perceived green product effectiveness on purchase intention was analyzed in the same way. A 95% confidence interval (CI) for the indirect effect was significant and excluded zero (β = −0.64, 95% CI: [−1.12, −0.20]); however, the interaction effect was not significant and included zero (β = −0.47, 95% CI: [−1.01, 0.56]). That is, perceived green product effectiveness fully mediated the interaction effects of advertisements strategy and resource scarcity on purchase intention (see Figure 7b).

Study 2 provided further support for the effect of the relationship between resource scarcity and green advertising appeals on green consumption, demonstrating that consumers’ attitudes and purchase intentions toward implicit (vs. explicit) green advertising appeals are higher when they perceive high-level (vs. low-level) personal resource scarcity, supporting Hypothesis 2. Unlike ecological resource scarcity, the perception of personal resource scarcity would stimulate consumers’ low construal level, motivating them to prioritize self-related benefits. Implicit green advertising appeals that highlight advanced functional features are more effective in improving consumers’ attitudes and purchase intentions toward green products. Conversely, when consumers perceive low levels of personal resource scarcity, explicit green advertising appeals with an emphasis on green products’ environmental characteristics will obtain a higher response. Moreover, study 2 confirmed the mediating effect of consumers’ perceived green products’ effectiveness underlying the relationship between green advertising appeals and the extent of personal resources scarcity, supporting Hypothesis 3b. As discussed in the Conclusions and Implications sections, these findings have significant implications for improving consumers’ green consumption intentions.

5. Conclusions and Implications

5.1. Discussion

The present research examined the impact of explicit and implicit green advertising appeals on consumers’ attitudes and purchase intentions, and how this effect varies depending on the extent of ecological resource scarcity (high vs. low) and personal resource scarcity (high vs. low). Across two experiments, we found that individuals’ green consumption intentions were promoted by explicit (vs. implicit) green advertising appeals when they were primed with a high (vs. low) level of ecological resource scarcity (study 1). To extend the relationship between resource scarcity and green consumption behavior, we further examined the boundary condition of personal resource scarcity. Different from the ecological resource scarcity condition, we showed that when consumers were exposed to a high (vs. low) level of personal resource scarcity, implicit (vs. explicit) green advertising appeals promoted their green consumption intentions more effectively (study 2). More importantly, we explored how the relationship between resource scarcity and green advertising appeals can be explained by consumers’ perceived green products’ effectiveness (studies 1 and 2); that is, when green messages expressed through advertisements align with consumers’ psychological states, such as the extent of perceived resource scarcity, they will perceive the green products as highly effective, leading to a positive attitude and purchase intention. By linking resource scarcity to the effect of green advertising appeals and revealing the driving factor of perceived green products effectiveness, the findings yield novel insights into green consumption, and have significant theoretical and practical implications.

5.2. Theoretical Implications

Our research has several theoretical implications.

First, we contribute to the advertising literature by demonstrating how explicit and implicit appeals can be utilized to construct effective advertising strategies. According to previous studies, the prominence of products’ environmental attributes is an important component of green advertising [53]. However, more direct communication of sustainable claims may not be consistently effective in encouraging pro-environmental intentions [54]. This is owing to the fact that consumers frequently associate green products with less effective performance [21]. To extend the literature, our research proposed that the effect of explicit and implicit green appeals is determined by two important factors: the extent of ecological resource scarcity and personal resource scarcity. Specifically, individuals would be encouraged to prioritize the welfare of external entities such as other people in group, the entire society, and even future generations if they were reminded of the high-level ecological resource scarcity. As a result, explicit green advertising that emphasizes environmental features will outperform implicit green appeals. Conversely, when confronted with high-level personal resource scarcity, consumers stick to self-focused viewpoints and are motivated to promote their own benefits, resulting in a preference for implicit green advertising appeals in the context of consumption. In this vein, the current study reveals that consumers’ perceived congruence with green advertising appeals and resource scarcity can effectively improve their attitudes and purchase intentions of green products, which contributes to the resolution of such conflict issues caused by the trade-off between sustainable benefit and traditional function.

Second, drawing on construal level theory, we divided resource scarcity into two categories, namely ecological and personal resource scarcity, and documented two psychological conditions influencing the effect of green advertising strategies. As we reviewed before, when individuals have a high (vs. low) level of future orientation, reminders of ecological resource scarcity have a favorable influence on promoting pro-environmental behaviors [18]. Based on this notion, our research further documented that ecological resource-related cues can stimulate consumers’ concern for the future living environment. Thus, explicit green advertising appeals are best served for consumers who perceived high-level ecological resource scarcity. We integrated the information of ecological resource scarcity to extend the existing research on how to improve green consumption behavior. In addition, personal resource scarcity would increase self-benefit and welfare, which are always patterns congruent with egoism. Previous research indicated that being exposed to personal resource scarcity impedes consumers from engaging in pro-social behaviors [13]. Unlike the existing literature, our study revealed that incorporating prominent function features of green products into advertising appeals can improve consumers’ attitudes and purchase intentions when they are suffering high-level personal resource scarcity, providing a novel perspective on how to persuade consumers to behave in a more pro-environmental manner to mitigate the negative effect of personal resource scarcity. Taken together, our findings illustrate the difference in attitude towards ecological and personal resource scarcity in the green consumption arena, expanding the concept of scarcity mindset to further green consumption research.

Third, we also extend the notion of green product effectiveness. We show that the relationship between green advertising appeals and resource scarcity are mediated by the perception of green product effectiveness. Prior research has provided sufficient evidence that processing fluency plays an important role in information processing and persuasion [55,56]. The effect of advertising appeals can be explained by processing fluency [20]. However, the current research offers a new viewpoint on the concept of green products effectiveness. Previous assumptions of sustainability suggested that green products were associated with low performance, poor quality, and short lifespan [29]. We find that improving consumers’ perception of green products’ effectiveness can lead to more favorable evaluations. In this respect, the current research proposed that the congruence of green messages and scarcity can powerfully facilitate the perception of green product effectiveness, which eventually leads to positive advertising attitudes and purchase intentions. This finding extends previous research and provides a more comprehensive understanding for exploring the psychological mechanism of consumers’ green consumption decision-making.

5.3. Practical Implications

The results of this article also have some practical implications. It would be prudent for marketers and firms to match advertisements with their appeal to consumers with different mental motivations. Extending this, firms would do well to emphasize the environmental attributes or functional features of green products in advertisements to satisfy the various expected consumer benefits. The current research suggests that the scarcity mindset may impact consumers’ evaluations of green advertising appeals. Specifically, when individuals perceive a high-level scarcity of ecological resources, companies can develop explicit green advertising to highlight sustainable benefits (e.g., low-carbon emission, saving energy, or environmental protection) of green products. For example, highlighting the severity of water resource shortage in the introduction of environmentally friendly laundry detergent, or emphasizing the preciousness of forest resources in the promotion of green paper pumping, chopsticks, and notebooks. At the same time, companies must emphasize the benefits of conventional functional aspects of products and convey environmental characteristics more indirectly to consumers who have no obvious perception of scarcity or are difficult to manipulate in the short term. For example, by emphasizing the cleaning capabilities of laundry detergent and the flexibility and water absorption properties of pumping paper, consumers are less likely to conclude that the product has sacrificed its conventional performance benefits in order to improve its environmental properties. Furthermore, marketers can combine the signals of ecological resource scarcity (vs. abundant) with explicit (vs. implicit) green appeals in product marketing to successfully match with target customers and increase the persuasiveness of green advertising. According to our findings, environmental organizations should consider using social media (e.g., Twitter, Facebook, and YouTube) to remind individuals of ecological resource scarcity and raise public awareness of environmental issues, combining explicit appeals (e.g., protect the environment, no delay) to encourage consumers to conserve ecological resources and protect the environment.

Moreover, when consumers perceive a scarcity of personal resources, they will pay more attention to the quality of goods, the cost, and the welfare of themselves and their family members. Therefore, emphasizing environmental attributes in green communication may have some detrimental effects. Marketers can use implicit green signals to downplay pro-environmental advantages while emphasizing conventional functional qualities (e.g., low cost, high quality, health, and safety) to ensure consumers’ self-interest in green consumption behavior. In contrast, it is better to use external clues for environmental consumption behavior once consumers perceive their personal resource scarcity as not apparent. That is, if companies use explicit green advertising for product promotion, they should avoid scarce personal resource cues, like reminding consumers time and money are exhausted in the marketing process, and should strive to create a phenomenon with abundant consumption resource cues. When consumers perceived high-level personal resource scarcity, conveying implicit signals to empathize the benefit for individuals (e.g., more green, more health) is effective. However, as resource depletion becomes more common, consumers may be unwilling to purchase environmental products as a consequence of being financially impacted by the COVID-19 pandemic. Marketers and policy makers can increase consumer preference for green products and recycling habits by satisfying their resource desires. For example, providing some presents as souvenirs, cash discounts, or E-coupons online might mitigate the negative impact of personal resource scarcity, which can assist in raising consumer preference for environmentally friendly behaviors.

More importantly, our findings suggest that a high level of perceived green product effectiveness is more helpful in promoting consumers’ attitudes and purchase intentions. Therefore, to overcome consumers’ skepticism regarding the effectiveness of green products, companies could give more credible messages (e.g., green authentication, credible endorsement, or consumer reports). In addition, advertisers need to focus on the perception of product performance in green consumption, especially the consistency between the benefits of green advertising appeals and consumers’ scarcity mindset.

5.4. Limitations and Future Research

The present research has several limitations for further research to explore. First, future research could replicate our experiments in an actual scenario to provide external validation. For example, researchers can select two stores with comparable business modes, emphasizing ecological/personal resource scarcity and abundance by using visual cues (e.g., slogan, promotional video, or space design), and record the actual sales data for green products promoted by explicit or implicit appeals to further test the credibility of the findings. Moreover, the current research focuses on regularly purchased products (e.g., laundry detergent and notebooks), but future research can extend to high involvement services (e.g., hotels, restaurants, and tourism), examining the robustness of the findings.

In addition, there are many types of resource scarcity. The current research mainly discusses the scarcity of ecological and personal resources from the perspective of construal level and benefit focus (self vs. other). In fact, consumers respond to scarcity through many psychological mechanisms. For example, temporary financial constraints are significantly different from chronic poverty. Future research can divide the forms of scarcity mindset more clearly and continue to focus on the impact of scarcity on consumers’ green consumption behavior from multiple angles.

Finally, we analyzed the mediating role of perceived green product effectiveness in demonstrating the interaction effect of green advertising appeals and resource scarcity. Further research could explore other boundary conditions and mechanisms underlying these impacts. For example, investigating the influence of explicit and implicit green advertising in the context of hedonic and practical products, or high-value and low-value green products, from the perspective of product types. In addition, examining other possible intermediary mechanisms, such as perceived green advertising content credibility, processing fluency, or perceived diagnosability, would contribute to a more comprehensive understanding of process psychology, and enrich relevant green advertising research.

5.5. Conclusions

Companies often struggle to find an effective strategy to communicate environmental messages through green advertisements. Previous research has found that the effectiveness of green advertisements is mostly determined by the form of advertising appeal. The current study proposed and examined when and how explicit and implicit green appeals might lead to a favorable evaluation of green products. Drawing on construal level theory and value congruity, we further identified the boundary condition of ecological resource scarcity and personal resource scarcity in the context of green consumption, assisting in reconciling previous contradictory findings in the trade-off between green products’ environmental attributes and their performance advantages. Moreover, we explored perceived green product effectiveness as a mechanism underlying the relationship between green advertising appeals and resource scarcity. This research provides strong support for the importance of the congruence between green advertising appeals and resource scarcity. Marketers and advertisers should pay more attention to matching consumers with the appropriate advertising appeals to fulfill their various needs and desires. Future studies can explore other mediators for improving pro-environmental behavior through green advertising appeals.