Introduction

Environmental protection issues have become increasingly important and urgent. Individuals’ daily behaviors can profoundly impact the environment (Lin & Hsu, 2015). For instance, daily consumption behavior can exert a considerable impact, such as the pollution from plastic shopping bags. Green purchase behavior is essential for achieving a sustainable future (Kim & Schuldt, 2018). Green purchase behavior empowers consumers to impact positively, influences businesses to adopt sustainable practices, and promotes a shift towards a more environmentally conscious society (Kohlova & Urban, 2020). By incorporating pro-environmental principles into their purchasing decisions, individuals can become catalysts for positive change and contribute to a more sustainable and resilient planet (Lin & Niu, 2018). Hence, promoting green purchase behavior will significantly contribute to environmental protection (Kim & Schuldt, 2018).

In addition, while taking action to address the grant environmental challenges, more and more countries are focusing on strengthening environmental education (Lin & Niu, 2018). Environmental education can help enhance people’s environmental awareness and promote a green and low-carbon lifestyle transformation. Particularly, one of the core aspects of environmental education is enhancing individual green knowledge (i.e., environmental knowledge; Paço & Lavrador, 2017). Recently, a growing body of research has pointed to the positive impact of green knowledge (Paço & Lavrador, 2017). However, the mechanism of green knowledge still needs further exploration (Fryxell & Lo, 2003). Thus, this research explores the underlying mechanism linking green knowledge to green behaviors, especially green purchase behaviors.

To solve this research question, this study draws on trait activation theory (Tett & Guterman, 2000) and green knowledge literature (Fryxell & Lo, 2003). Trait activation theory states that an individual’s conduct results from the mutual interplay of personal traits and situational determinants (Tett & Guterman, 2000; Tett et al., 2021). Furthermore, recent progress in trait activation theory (Tett et al., 2013) has incorporated “non-trait-like” attributes as knowledge into the activation process research. As verified in recent environmental behavior research, the exhibition of environmental behaviors can be viewed as a trait-activation process (Song et al., 2023; Tian & Suo, 2021). For instance, responsible leadership can activate employees’ perceived role of ethics and social responsibility to behave pro-environmentally (Tian & Suo, 2021). Hence, the influencing process of green knowledge can be viewed as an activation process. In addition, various research findings have found that the higher level of information individuals hold on environmental issues (e.g., green knowledge), the greater their concern will be (Paço & Lavrador, 2017). Consequently, the greater concern over environmental issues, the more pro-environmental behaviors will be enacted.

Further, trait activation theory also highlights the activation effect of contextual clues (Tett & Guterman, 2000). The environment in which an individual lives can have a subtle influence on the individual’s psychology and behavior (de Groot et al., 2021). Especially, the environment will shape individuals’ pro-environmental behaviors (Ray et al., 2021). When resources are scarce, individuals are more aware of the preciousness of resources and the importance of environmental protection. Living under resource inadequacy (Pitesa & Thau, 2018), individuals will have a more profound experience and understanding of the importance of environmental protection (Schiller et al., 2022). Thus, this study points out that the scarcity of resources in the environment can strengthen the influence of green knowledge. Therefore, this study further proposes that the promoting influence of green knowledge on green purchase behavior will be strengthened by resource inadequacy (Chakravarthy & Booth, 2004). In sum, this study proposes a moderated-mediation model to reveal how and when green knowledge can foster green purchase behavior (shown in Fig. 1).

Fig. 1
figure 1

The conceptual model.

Full size image

This research will make several contributions. First, this study extends the outcomes of green knowledge (Ünal et al., 2018), enriching its specific influence on individuals’ green purchase behaviors. Second, this study enriches the environmental concern (Poortinga et al., 2004; Sevillano et al., 2007) as the underlying mechanism linking green knowledge and green purchase behaviors. In this vein, the exploration of underlying mechanisms also contributes to a deeper understanding of green knowledge (Fryxell & Lo, 2003). Third, this research contributes to the antecedents of green purchase behavior (Paço & Lavrador, 2017). Green knowledge can promote more green purchase behaviors. In addition, incorporating resource inadequacy (Pitesa & Thau, 2018), this study enriches the boundary condition of green knowledge. The environment can greatly influence individuals’ psychology and behavior. Finally, this study extends the application of trait activation theory (Tett & Guterman, 2000) in pro-environmental behavior research. Integrating individuals (i.e., green knowledge in our study) and the situation (i.e., resource inadequacy) with a trait-activation perspective, this study enriches perspectives on human-environment interactions for a deeper understanding of psychology and behavior.

Theoretical background and hypotheses

Green knowledge, environmental concern, and green purchase behavior

Trait activation theory (Tett & Guterman, 2000) clarifies how external situations can activate an individual’s internal attributes and subsequently result in observable behaviors (Tett et al., 2021). According to Tett and Guterman (2000), trait activation is the process by which individual internal attributes exhibit as specific behaviors. Then, Tett and colleagues (2013) proposed an extended model of trait activation theory, incorporating more “non-trait-like” attributes, such as knowledge. Thus, from this perspective, knowledge, as individual attributes, can also be activated.

Fryxell and Lo (2003) defined environmental knowledge (green knowledge) as general knowledge about the facts, concepts, or relationships as regards the surrounding environment and its ecosystems (Fryxell & Lo, 2003; Lin & Niu, 2018). Being aware of the environment means how human behavior impacts the environment and taking corrective actions (Farrukh et al., 2022). Individuals with more green knowledge can deeply understand the profound influence of their daily behaviors on the environment (Duerden & Witt, 2010), including their consumption behaviors. They will better know which behaviors are good for environmental protection. With such a reservoir of green knowledge (Chaihanchanchai & Anantachart, 2022), individuals with more green knowledge can behave in a more clear way, since they can determine whether or not to act pro-environmentally.

Green knowledge prompts individuals to value environmental issues highly (Polonsky et al., 2012). They will act more cautiously when making purchase decisions. They might pertain to a long-term perspective and incorporate the ecological impact into consideration. Individuals with more green knowledge (Sun et al., 2018) will better understand the far-reaching adverse effects of environmentally unfriendly behaviors. For instance, they will know more about the pollution effects of plastic packaging bags. Thus, such knowledge will raise more concerns about protecting the environment (Poortinga et al., 2004; Sevillano et al., 2007). Environmental concerns are vital cognitive factors that explain individuals’ eco-friendly and responsible behavior and decision (Foroughi et al., 2022).

With environmental concerns (Bamberg, 2003; Enzler et al., 2019; Hansla et al., 2008), individuals with more green knowledge will produce a higher tendency to behave pro-environmentally (Wyss et al., 2022). When making purchase decisions, they will prefer products with minimal environmental impact. They are more likely to form environmentally friendly consuming habits (Lin & Hsu, 2015; Peattie, 2010). That is, the more individuals know, the more they will worry and the more they will act (Meinhold & Malkus, 2005). Thus, we propose that green knowledge can promote more concerns for the environment (Lou & Li, 2021; Syropoulos & Markowitz, 2021) and then encourage individuals to consume more pro-environmentally (Pawaskar et al., 2018):

H1: Environmental concern mediates the positive relationship between green knowledge and green purchase behavior.

Moderating role of resource inadequacy

Trait activation theory emphasizes that appropriate situational cues can enhance the influence of intrinsic traits and attributes (Tett & Burnett, 2003). From a unique perspective of interaction psychology, trait activation theory explores the organic link between external contexts and intrinsic attributes of individuals, and the predictive role of this organic link on individual behaviors (Tett & Burnett, 2003). Researchers also found that suitable situational factors can strengthen the activation process of individual environmental behaviors (Song et al., 2023; Tian & Suo, 2021).

The environment individuals live in can subtly influence individuals’ feelings and behaviors (Chang et al., 2022). Resources in the ecosystem, such as food and water, are essential environmental factors that affect every species’ existence, including humans (Chakravarthy & Booth, 2004). Human survival is drastically affected by the availability of resources in the environment (Pitesa & Thau, 2018). Notably, resource inadequacy in the environment can profoundly affect individuals’ psychology and behaviors. For instance, researchers have found that resource scarcity promotes competition among residents for resources from an insufficient pool (Chang et al., 2022).

When resources are scarce, individuals are more aware of the preciousness of resources and the importance of environmental protection (Sachdeva, Zhao (2021)). Living in a place without enough resources, individuals will feel a stronger sense of uncertainty and danger (Gu et al., 2020; Pitesa & Thau, 2018), worrying more about the shortage of resources. Thus, individuals facing resource inadequacy will be more sensitive to environmental issues. They will devote more effort to protecting the environment and limited resources (Pitesa & Thau, 2018). With the knowledge about the environment, people living in resource inadequacy will have more concerns about environmental development. Thus, resource inadequacy will strengthen the influence of green knowledge on environmental concerns:

H2: Resource inadequacy moderates the positive relationship between green knowledge and environmental concern, such that the positive relationship will be stronger when resource inadequacy is high.

Taken together, the environment will influence both individuals’ feelings and behaviors (Chang et al., 2022). Under resource inadequacy, individuals with more green knowledge will have more environmental concerns and then take more actions to overcome their concerns, as greener consuming behaviors:

H3: Resource inadequacy moderates the indirect positive relationship between green knowledge and green purchase behavior, such that the positive relationship will be stronger when resource inadequacy is high.

Methods

Participants and procedure

We collected survey data from a Chinese university during the summer vacation, at which time students were staying at their homes. We issued 800 surveys and finally obtained 606 valid university students’ responses. Common method variance (i.e., variance that is attributable to the measurement method rather than to the constructs the measures represent) is a potential problem in behavioral research (Podsakoff et al., 2003). Hence, to reduce the common method bias, we followed suggestions from previous studies (Podsakoff et al., 2003) and collected data at three time points with a two-week interval. We used student ID as the match code for students’ multiple responses. At Time 1, university students reported their basic information (i.e., age, gender, their major), green knowledge, and resource inadequacy. At Time 2, students reported their environmental concerns. Finally, at Time 3, they reported their green purchase behavior. Among our final valid sample, 315 (52.00%) students are male, with an average age of 20.27 (SD = 1.88). Furthermore, 128 (21.12%) students major in social science.

Measures

All the responses were rated on a five-point Likert scale, ranging from 1 (not at all, totally disagree, never) to 5 (completely, totally agree, always). We followed Brislin’s (1980) translation-back-translation procedure to translate English scales into Chinese versions.

Green knowledge

This study measured green knowledge with four items from Ellen (1994). Items include “Trying to figure out the best packaging in terms of the effects on the environment is very confusing (reversed); I am very confident that 1 buy products in packages which are environmentally safe; I know more about recycling than the average person; Every time I turn around, the “experts” are changing their minds about what are the “best” products or packages to buy (reversed)” (α = 0.87).

Resource inadequacy

This study measured resource inadequacy with five items from Pitesa and colleagues (2018). Items include “There is not enough resources for everyone; Essential resources (food, water) are scarce; I worry that acquiring all the necessary resources will become increasingly difficult; Shortages of essential resources are possible; I am concerned about my long-term ability to acquire essential resources” (α = 0.89).

Environmental concern

This study measured environmental concern with four items from Lee et al. (2014). Items include “If things continue on their present course, we will soon experience a major ecological catastrophe; Humans are severely abusing the environment; The balance of nature is very delicate and easily upset; Despite our special abilities, humans are still subject to the laws of nature” (α = 0.87).

Green purchase behavior

This study measured green purchase behavior with six items from Lee et al. (2014). Items include “I purchase products that are less environmentally harmful; I purchase organically grown produce; I purchase products that are made by an eco-friendly business; I buy a green version of a product; I switch to a different brand for ecological reasons; I avoid purchasing foods containing chemicals such as preservatives” (α = 0.93).

Results

Preliminary analysis

Methodically, the item loading between a construct and its indicators indicated that all indicators (higher than 0.6) are valid, which implied that the convergent validity is accepted. The results of item loading can be seen in Table 1.

Table 1 Psychometric characteristics of measures.
Full size table

The hypothesized four-factor model fitted well (χ2(146) = 467.27, χ2/df = 3.20, CFI = 0.96, TLI = 0.95, SRMR = 0.04, RMSEA = 0.06) and was significantly better than other alternative models (see Table 2), showing good discrimination validity. These results showed that there are no severe common method biases.

Table 2 Confirmatory factor analysis (N = 606).
Full size table

Table 3 presented the descriptive analysis results of all variables. As shown in Table 3, green knowledge was positively correlated with environmental concern (r = 0.34, p < 0.01). Environmental concern was positively correlated with green purchase behavior (r = 0.48, p < 0.01). The correlation results provided initial support for our hypotheses.

Table 3 Means, SD, correlations among variables (N = 606).
Full size table

Hypotheses test

To test our hypotheses, we conducted a series of regression analyses by Mplus. First, we regressed green purchase behavior on green knowledge and environmental concern. The mediation test indicated that environmental concern significantly mediated the positive relationship between green knowledge and green purchase behavior (Estimate = 0.11, SE = 0.02, 95%CI = [0.08, 0.15], didn’t include 0), supporting H1.

Then, we conducted hierarchy regression analyses to test the moderating effects of resource inadequacy. As shown in Table 4, resource inadequacy significantly moderated the positive relationship between green knowledge and environmental concern (Estimate = 0.09, SE = 0.03, p = 0.005), supporting H2. Then, we conducted a simple slope analysis to explore the specific moderation pattern. Results of simple slope analysis (shown in Fig. 2) indicated that the positive relationship between green knowledge and environmental concern was stronger when resource inadequacy was higher (b = 0.23, t = 4.14, p < 0.001; 1 SD above mean) than lower (b = 0.10, t = 1.81, p = 0.071; 1 SD below mean).

Table 4 Regression results (N = 606).
Full size table
Fig. 2
figure 2

The moderating role of resource inadequacy.

Full size image

Further, the overall moderated mediation test indicated that resource inadequacy significantly moderated the indirect influence of green knowledge on green purchase behavior via environmental concern, supporting H3. Specifically, the indirect influence of green knowledge on green purchase behavior via environmental concern was stronger when resource inadequacy was higher (effect = 0.20, SE = 0.06, 95%CI = [0.09, 0.31], 1 SD above the mean) than lower (effect = 0.15, SE = 0.04, 95%CI = [0.08, 0.23], 1 SD below the mean; Estimated difference = 0.05, SE = 0.02, 95%CI = [0.01, 0.08]).

Discussion

Based on trait activation theory, this study proposes that individuals with more green knowledge will have more concerns about environmental protection and act more pro-environmentally (i.e., green purchase behavior in our study). Meanwhile, aligning trait activation theory to incorporate the environment people live in, this study further proposes that resource inadequacy will strengthen the positive effects of green knowledge. Results from a multi-time survey study verified the hypotheses.

Theoretical implications

This research makes several theoretical contributions. First, this study contributes to green knowledge research by enriching its outcomes (Lin & Niu, 2018). Specifically, this study revealed how and when green knowledge could foster green purchase behavior (Peattie, 2010). Individuals with more green knowledge can obtain a deeper understanding of their daily behaviors’ environmental impact and thus act more pro-environmentally.

Second, this study enriches environmental concerns as to how green knowledge exhibits its influence. Enriching environmental concern (Poortinga et al., 2004; Sevillano et al., 2007) as the underlying mechanism, this study establishes the linkage between green knowledge (Fryxell & Lo, 2003) and green behaviors (Ünal et al., 2018). Third, this study also helps to expand the antecedents of green purchase behavior (Paço & Lavrador, 2017). Green knowledge can promote individuals’ green purchase behavior (Riva et al., 2022) by eliciting concerns about environmental protection (Wu & Yang, 2018). Meanwhile, this study revealed the mechanism role of individual environmental concerns (Poortinga et al., 2004).

In addition, by incorporating the environment (i.e., resource inadequacy in our study) into research, this study also extends the subtle influence of the environment on individuals’ feelings and behaviors (Chang et al., 2022). This study highlights the strengthening influence of resource inadequacy in the green knowledge-green purchase behavior activation process. Finally, this study contributes to environmental research by applying a trait activation perspective (Tett & Guterman, 2000), which can help enlighten more theoretical perspectives. This study extends perspectives on human-environment interactions by integrating individuals (i.e., green knowledge in our study) and situations (i.e., resource deficiency in our study) with a trait-activation (Tett et al., 20) viewpoint for a fuller understanding of psychology and behaviors in environment protection.

Practical implications

This research also has several practical implications. First, this research highlights the importance of green knowledge (Ünal et al., 2018). The results enlighten us to strengthen the implementation of environmental protection knowledge education. Educators could design more training for green knowledge (Lin & Niu, 2018). Teachers should take an active role as role models in the classroom and promote the dissemination of green knowledge (Sun et al., 2018). For the government, this research inspires policymakers to formulate corresponding policies to promote environmental education (Fryxell & Lo, 2003). For instance, strengthening environmental laws and systems will be highly effective.

Moreover, this research inspires us to understand the significance of green purchase behaviors in environmental protection. Green consumption is also a crucial aspect of environmental protection. Small actions can make a big difference (Kohlova & Urban, 2020). The great impact of green consumption also highlights that manufacturers should practice corporate social responsibility and perform their duties regarding environmental protection (Yang et al., 2015). For instance, producers can use more environmental protection materials to limit the environmental damage caused by production.

Limitations and future directions

First, this study only conducted one survey study, which is insufficient to make causal conclusions. Future researchers could supplement more experiments (Podsakoff & Podsakoff, 2019) to help draw causal conclusions. For instance, future studies may apply green knowledge training interventions. Second, this research only collected data from Chinese university students. However, there might be some cultural differences (Sun et al., 2018) in environmental protection awareness. In addition, university students may not be the primary purchasers of products in the summer and in their parent’s household, which is limiting our generability. Hence, future researchers may supplement more general consumer samples to replicate our findings, enhancing external validity and robustness. Third, this research only focuses on green purchase behaviors for pro-environmental behaviors (Kohlova & Urban, 2020).

In addition, future research can enrich more theoretical perspectives and supplement more underlying mechanisms. For instance, the potential influence of emotional responses in shaping green consumption behaviors may provide new avenues for research and allow for new approaches to influencing consumer behavior (Peattie, 2010). The influence of expectations and a sense of responsibility on consumption behaviors also remains under-researched, and the potential for expectations management to motivate pro-environmental behaviors is worth exploring (Peattie, 2010).

Meanwhile, future research could expand other pro-environmental behaviors, such as environmental appeals, environmental volunteering, and other behaviors. Future research could focus not only on specific environmental behaviors, but also on the development of environmental behavior habits. The long-term positive development of environmental behavior is also worth exploring (Peattie, 2010). Moreover, the potential influences of group norms and collective consumption initiatives and behaviors are likely to emerge as a significant field for future research (Peattie, 2010), such as the influence of environmental climate.

Conclusion

From a trait activation perspective, this study explored how green knowledge shapes green behaviors. Specifically, this study proposed that green knowledge can elicit higher environmental concern and further promote green purchase behaviors, further strengthened by resource inadequacy. Results from a multi-time survey study with Chinese university students supported the hypotheses and achieved the research objectives. We hope this study can inspire more studies on green knowledge and purchase behaviors, further promoting research on environmental protection.