Abstract
This research responds to challenges in promoting more sustainable responses among travelers. We posit that the commitment-and-consistency principle is a potent driver of more sustainable codes of conduct. Four experiments with more than 3,000 participants tested the impact of active (vs. passive or no) commitment on travelers’ likelihood to make sustainable choices at airports. A positive effect of active commitment emerged regarding travelers’ likelihood of making sustainable choices, with their consistency effort mediating this effect. Cultural belonging moderated this interplay, with active commitment being particularly powerful in individualistic (vs. collectivist) cultures. These findings contribute to commitment literature, offering actionable insights for airport managers, environmental NGOs, and policymakers alike. Specifically, our findings document that the cost-effective reliance on active commitment at commercial airport facilities boosts travelers’ general choice likelihood of sustainable options by roughly 50% to 75% compared to the existing (no commitment) status quo across settings and study paradigms.
Keywords
Introduction
The global travel and tourism landscape is undergoing a profound transformation, driven by pressing needs to mitigate the sector’s high environmental impact (Papatheodorou, 2021). This shift is particularly noticeable in the aviation sector, which is considered central for the travel and tourism industry (Kumar et al., 2020). The aviation sector is currently acting as a pivotal hub, leaving a substantial contribution to the world’s gross domestic product (Sebastian & Louis, 2021). Market pundits argue that demand in the aviation industry is propelled by various factors such as escalating global population, urbanization, economic growth, and the quest among travelers to explore every corner of the planet (Aguinis et al., 2023). It is also predicted that this expansion is not going to slow down anytime soon (Sebastian & Louis, 2021). The growth extends beyond aviation operations, with airports evolving from transit points into multifaceted complexes encompassing shopping centers, recreational facilities, hotels, and restaurants, thereby becoming an integral part of the broader travel and tourism experience.
Scholars argue that alongside the evident economic and logistical significance of the aviation sector, the escalating environmental footprint of its operations raises urgent concerns (Gössling et al., 2023). Specifically, issues related to waste generation and unsustainable consumption practices among passengers at airports and during flights emerge as critical points requiring immediate attention. Airline passengers contribute significantly to waste production. According to the International Air Transport Association (IATA, 2023), a typical passenger generates approximately 1.43 kg of cabin waste per flight, ranging from 0.83 to 2.5 kg, depending on flight duration and service class. Beyond in-flight waste, airports themselves generate significant amounts of waste due to retail, food and beverage sales, and operational activities. Estimates suggest that each airport passenger produces roughly 0.5 kg of waste while passing through an airport (Waste Today, 2023). This includes diverse kinds of waste at airport terminals. A recent report (Aviation Benefits Beyond Borders, 2024) estimates that passengers alone generate a staggering 6 million tons of waste at airports globally, much of it being single-use items like to-go cups, plastic cutlery, and packaging.
In response to the growing problem of waste generation at airports, aviation administration authorities have advocated for sustainability practices in airport planning, design, and operations (Sebastian & Louis, 2021). Collaborating with airlines and retailers, airport operators implement policies promoting sustainability, including the adoption of eco-friendly materials and waste reduction initiatives. These policies extend to energy-efficient practices and integrating renewable energy sources, striving for a harmonious balance between economic prosperity, environmental responsibility, and social considerations (Sebastian & Louis, 2021).
While regulatory measures address these concerns, a complementary strategy includes intentionally shaping travelers’ behavior to embrace sustainable choices (Aley et al., 2023). For example, airports actively engage in public awareness campaigns, utilizing signage, announcements, and digital media displays to educate travelers about the environmental impact of their choices and encourage sustainable behaviors (Albrecht & Raymond, 2021). Given the pivotal role of airports as gateways to diverse tourist destinations, there is an urgent need to promote sustainable choices among travelers in this context.
While some studies advocate for strategies that engage travelers in waste reduction, passenger participation is often a significant challenge for sustainable waste management at airports (Sebastian & Louis, 2021). Despite recognizing the global environmental concern of waste at airport terminals, previous literature has primarily focused on strategies for airports and authorities to reduce waste generation (Lopez-Valpuesta & Casas-Albala, 2023). Hence, there are several focal gaps in understanding how travelers can actively contribute to maintaining a clean environment through modified behaviors. First, the focus of the prior literature is on waste reduction strategies by aviation and airport authorities rather than travelers themselves. Second, there is a lack of research examining the efficacy of behavioral interventions to encourage sustainable choices among travelers at airports. Third, it remains to be investigated how diverse cultural backgrounds contribute to waste generation and sustainable practices.
Airports are critical and unique touchpoints, influencing travelers’ behavior in ways that differ from other service environments due to time scarcity, cognitive load, and heuristic-driven decision-making coupled with lacking abilities to build familiarity in these settings over time and across repeated visits (Bröder, 2003; del Campo et al., 2016). Travelers at airports often experience decision fatigue as a function of navigating security procedures, tight schedules of connecting flights, and other logistical complexities, making them more likely to default to habitual choices (DeFrank et al., 2000). Unlike stores in consumers’ immediate vicinity (e.g., local cafés), which customers might visit regularly, airports thus serve as an opportunity to study how one-time interventions influence immediate pro-environmental actions, making them a more rigorous test arena for such interventions compared to settings where repeated exposure to certain messages might reinforce sustainability-oriented responses over time. Moreover, airports serve as relatively controlled environments where millions of passengers pass through daily, but with a relatively narrow set of choice options within the terminals themselves. As a result, consumption choices may be effectively influenced in these semi-structured settings, making them ideal locations to test behavioral interventions. To this end, the current research aims to examine the active role travelers can play in reducing waste generated at airports through various interventions, with a specific emphasis on sustainable consumption choices. To achieve this main objective, we draw on the commitment-and-consistency principle (Cialdini & Goldstein, 2004), which is a well-known social influence principle positing that individuals are more prone to adhere to a given course of action if they have actively committed to it in advance.
We focus on cup choices at airport coffee shops, as these settings frequently offer customers the chance to choose whether to get their hot beverages either in (sustainable) reusable porcelain mugs or (unsustainable) disposable to-go cups with plastic. Unlike typical café settings, where customers might bring their own reusable cups, airport travelers often rely on disposable options as the default due to security restrictions, time constraints, or convenience. This makes the waste reduction potential particularly impactful at airports, as behavioral interventions can override such unsustainable default tendencies by prompting travelers to make sustainable choices instead. Even small shifts in travelers’ behavior in these settings (e.g., opting for a reusable cup instead of a disposable alternative) can have massive environmental benefits at the aggregate level, considering the sheer volume of passengers, amounting to 8 billion annually (Airport Council International Report, 2023). Indeed, airport cafés and coffee shops rank among the busiest retail outlets at airport terminals, with many million to-go cups sold annually and with food and beverage spending per passenger increasing significantly in recent years (Airport Industry Review, 2020). For example, Brussels airport alone sells approximately 10,000 cups of coffee daily (Brussels Airport, 2019), whereas Dublin airport reports selling a tea or coffee every 12 s, summing up to over 2.5 million cups in 2024 (RTE, 2024). Therefore, we focus on cup choices as our focal dependent variable.
Theoretical Framework and Hypotheses
Travel Behavior and Environmentally Friendly Choices
The literature on consumer behavior within the context of environmentally friendly choices has grown significantly in recent years. Among the focus areas in this stream of literature is understanding the factors that influence individuals’ decisions to engage in sustainable practices, often in travel-related contexts (Han, 2021). As illustrated in Figure 1, this body of work has mainly explored two influential factors, namely external norms and internal values (Li et al., 2019; van Riper & Kyle, 2014). To understand how individuals can be encouraged to adopt environmentally friendly practices, scholars have tried various behavioral modification strategies, with deliberate efforts to influence and guide sustainable actions (Baca-Motes et al., 2013; Li et al., 2019).
Factors influencing sustainable consumption decisions.
One prevalent approach to encourage sustainable behavior involves leveraging external norms (Wattanacharoensil et al., 2024). External norms refer to the standards, expectations, or rules of behavior that are established by a group, society, or culture. These norms guide individuals in their interactions and help maintain order within a community. For example, a study on hotel towel-reuse programs underscored the impact of social norms on hotel guests’ codes of conduct, with such norms significantly increasing towel-reusage rates compared to standard environmental messages typically found in hotel rooms (Goldstein et al., 2008).
Despite extensive research on external norms, challenges persist in translating environmental awareness into concrete behavioral change, as evidenced by hotel towel-reuse programs in the hospitality industry, where compliance rates only range between 30% and 38% (Baca-Motes et al., 2013). Attitude change, commonly targeted through environmental pleas and awareness campaigns, has been a strategy to encourage sustainable behavior. However, empirical evidence suggests that attitude change alone may not guarantee corresponding shifts in behavior (Holmes et al., 2021), especially among environmentally conscious individuals. This raises questions about the effectiveness of traditional methods focusing on altering attitudes without directly addressing conservation behavior.
The literature above underscores the need for a more nuanced understanding of the role of internal values and intrinsic motivations in driving sustainable choices and highlights the limitations of solely relying on external norms or attitudes for achieving meaningful behavior change. In contrast to external norms, internal values tap into individuals’ intrinsic motivations and internalized beliefs. For instance, personal values related to environmental consciousness play a pivotal role in guiding eco-friendly choices (Ahmad et al., 2020). These values, unique to each person, reflect core beliefs, such as commitment to environmental conservation for the well-being of future generations (Han, 2021). Despite limited prior research on the impact of internal values on behavioral modification, there is a need to explore such aspects in greater depth. This involves focusing on the commitment-and-consistency principle (Cialdini et al., 1999), which postulates that individuals are more likely to adhere to a chosen course of action if they have actively committed to it. By tapping into individuals’ internal values, this principle becomes a powerful tool to change travelers’ attitudinal and behavioral responses. The current research leverages this principle to encourage travelers to actively commit to practicing sustainable responses at airports.
The Commitment-and-Consistency Principle
Active commitment, involving explicit and voluntary agreement to adopt environmentally friendly practices, has been suggested as a powerful tool in promoting sustainable choices (Albrecht & Raymond, 2021). This aligns with the broader theoretical framework of the commitment-and-consistency principle, which posits that individuals have a psychological inclination to maintain internal consistency in their beliefs and actions, especially if the commitment is active, public, and self-selected (Cialdini et al., 1999). Active commitment is considered a potent trigger for this principle, as individuals who make explicit commitments are more likely to exhibit behavior consistent with those commitments (Backhaus et al., 2023; Dhir et al., 2024; Kamath et al., 2023). Studies within various domains have demonstrated that individuals who actively commit to a given course of action are more likely to follow through with congruent subsequent responses (Bhattacharyya et al., 2023; Cialdini et al., 1999; Majid et al., 2024). Hence, we hypothesize:
Consistency Effort as a Plausible Mediator
Consistency, as a psychological principle, suggests that individuals strive to maintain alignment between their attitudes, beliefs, and behaviors (Zollo, 2021). In the context of sustainable choices, we posit that individuals who actively commit to practicing environmentally friendly behaviors may experience increased consistency effort, driving them to align their choices with their committed stance (Li et al., 2019). Building on the commitment-and-consistency principle, we therefore predict that the effect of active commitment on travelers’ likelihood of making sustainable choices should be mediated by individuals’ consistency effort. In other words, active commitment is expected to amplify the internal drive to maintain consistency, in turn influencing the alignment between one’s commitment and subsequent choice patterns. Accordingly, we hypothesize:
Cultural Belonging as a Boundary Condition
The impact of cultural factors on consumer attitudes, intentions, and behavior is well-established. Individualistic and collectivist cultural orientations have been found to shape values, attitudes, and decision-making processes (Kim & Markus, 1999; Otterbring et al., 2024). However, cultural identities are increasingly fluid, with hybrid orientations emerging due to globalization, urbanization, and exposure to diverse cultural norms (Hamamura, 2012). This complexity underscores the need to interpret cultural differences through a nuanced perspective.
Limited research has delved into the interplay between cultural orientation and the effectiveness of the commitment-and-consistency principle (Cialdini et al., 1999), especially with respect to promoting sustainable responses among travelers. We predict that the effectiveness of active commitment strategies in promoting sustainable responses should vary across cultures, with culture exerting a moderating role into the link between active commitment and travelers’ likelihood of choosing sustainable options. Specifically, people in individualistic cultures, where personal autonomy and self-expression are highly valued, should be particularly affected by active commitment compared to their counterparts in collectivist cultures, where social alignment and group harmony typically exert a greater influence in decision-making (Koo, 2022; Lomas et al., 2023). Stated differently, as active commitment is internally focused (Baca-Motes et al., 2013; Cialdini et al., 1999) and people from individualistic cultures tend to be more internally focused while scoring higher in self-orientation, whereas people from collectivist cultures generally are more externally focused and score higher in other-orientation (Oyserman & Lee, 2008; Triandis, 2001), active commitment should have a more pronounced impact on individualistic (vs. collectivist) individuals. Support for this notion has been provided by Cialdini et al. (1999) using both person-specific scores in individualism and collectivism and group scores based on nationality (individualistic vs. collectivist countries). Accordingly, we hypothesize:
Further, we propose that the moderating effect of cultural belonging (individualistic vs. collectivist) on the relationship between active commitment and choice likelihood of sustainable options should be mediated by travelers’ consistency effort. Indeed, individuals who score higher in consistency effort or have a greater preference for consistency tend to be more prone to act in accordance with their prior commitment (Cialdini et al., 1995; Nichols & Webster, 2014), especially if they come from individualistic (vs. collectivist) cultures (Petrova et al., 2007; see also Cross et al., 2003). This suggests that the cultural context not only directly influences the effectiveness of active commitment but also shapes the psychological mechanism driving such choice behavior by means of the degree of consistency effort exerted by travelers in adhering to their prior commitment. Formally stated, and as depicted in our conceptual model (see Figure 2), we hypothesize:
Conceptual model.
Overview of Studies
The current research used a series of high-powered experiments to examine how active commitment causally influences travelers’ likelihood of making sustainable choices and exhibiting other pro-environmental behaviors at airports. Such experimental work, commonly referred to as randomized controlled trials, is often described as the gold standard when scholars want to demonstrate cause-effect relationships (Della Vigna & Linos, 2022). All studies were designed to balance internal and external validity, thus bridging rigor with realism and generalizability (Morales et al., 2017). In terms of internal validity, all experiments were conducted under controlled and rigorous conditions, which accounted for several potential bias sources, relied on powerful manipulations, and included outcomes discussed in previous research (H. Lin et al., 2021). In terms of external validity, we tested multiple different message types, used a variety of samples, employed several distinct key outcomes, with our experiments also consistently embedded within realistic settings (Otterbring et al., 2023). Study 1 investigates the impact of active (vs. passive or no) commitment on travelers’ inclination to make sustainable rather than unsustainable choices while awaiting their flights, such as selecting a hot beverage in a reusable porcelain cup instead of a non-reusable to-go cup with plastic. Building on the insights from this initial experiment, Studies 2A-B replicate and extend the findings to other “green” airport actions, while also providing evidence for the psychological mechanism driving our focal effects. Specifically, we identify travelers’ consistency effort as a theoretically relevant mediator through which our key findings emerge. Finally, Study 3 examines the generalizability and cross-cultural variability of the observed effects by testing whether travelers’ cultural orientation moderates the link between active commitment and our focal outcomes. Although active commitment significantly boosts choice likelihood of sustainable options and travelers’ inclination to exhibit other “green” airport actions across cultures, interventions based on this social influence principle is particularly powerful among travelers from individualistic rather than collectivist cultures, largely because the former react with stronger consistency effort than the latter following such active commitment interventions.
Study 1: The Main Effect
Study 1 sought to document the main effect of active commitment on travelers’ likelihood of choosing sustainable options and, hence, test
Participants were told to imagine themselves being at an airport, having checked in and passed the security area. As part of the scenario, they realize that they have some spare time before the boarding of their flight starts, so they decide to visit a coffee shop to get something warm to drink. Eventually, a barista asks them what they would like to get. Those in the control condition were then immediately told the following, “Before preparing your ordered drink, the barista asks whether you prefer to get it in a disposable to-go-cup or in a reusable cup of porcelain,” and were asked to make a binary choice between these options.
Participants in the passive commitment condition received additional information before being asked to make the same choice. Specifically, they were told the following prior to the binary choice: “Toward the end of the ordering process, the barista points to a sign right next to the menu stating the coffee shop’s commitment to the environment. The sign reads as follows: ‘We have long been a steward of the environment. At our coffee shop, we have a number of efforts in place to care for our planet ranging from water and energy conservation and recycling to eco-conscious options for airport guests.’”
Finally, participants in the active commitment condition received the same information as those in the passive commitment condition; however, they had to indicate whether they committed to practice environmentally friendly behavior at the coffee shop (yes vs. no) before making their binary choice. Our dependent variable has been used in previous related research (Loschelder et al., 2019) and captures whether a sustainable or unsustainable option is selected.
Once participants had made their beverage choice, they replied to a 16-item battery of binary social desirability measures from Larson (2019). These items (e.g., “I always admit my mistakes openly and face the potential negative consequences.”) were included to increase the internal validity of the study, considering that sustainable consumer behaviors are often perceived as socially desirable (Folwarczny et al., 2022). The items were averaged to form a composite social desirability index (Cronbach’s α = .75); see the Supplemental Materials for robustness checks and additional analyses across all studies.
At the end of the study, participants replied to two manipulation checks, with the first asking whether their assigned scenario stated something about the coffee shop’s commitment to the environment (yes vs. no) and the latter asking whether participants were asked to actively commit themselves to practice environmentally friendly behavior at the coffee shop (yes vs. no). Note that these manipulation checks and those used across all other studies relied on binary outcomes. Such binary manipulation checks are common in experimental research (e.g., Cheng & Mukhopadhyay, 2024; Lagowska et al., 2024). We deliberately included these manipulation checks at the end of the experiment to avoid demand effects such as hypothesis guessing and to ensure that our manipulation in and of itself influenced participants’ subsequent responses. This cannot be ascertained if manipulation checks are placed before the focal dependent variable (Hauser et al., 2018; Kühnen, 2010). All manipulations were effective across studies and were verified by our manipulation checks. For brevity, we report the manipulation check analyses in the Supplemental Materials.
Results
To test our main hypothesis, we performed a 2 (condition: active commitment vs. control and passive combined) × 2 (cup choice: sustainable vs. unsustainable) chi-square analysis using orthogonal contrasts. This distribution-free test examines whether expected frequencies differ significantly from the observed frequencies in one or more categories of a contingency table using a nominal variable, and do not have the same strict assumptions as those existing for parametric tests (McHugh, 2013). The chi-square analysis revealed a significant effect, χ2(1, N = 422) = 24.03, p < .001, V = 0.24. Consistent with
Discussion
Study 1 provides initial evidence for the powerful potential of the commitment-and-consistency principle. Reliance on this principle led to a significant increase in the proportion of travelers who made a sustainable rather than unsustainable cup choice in an airport coffee shop setting. Importantly, however, the commitment had to be active to carry clear downstream effects on travelers’ sustainable choice likelihood. Indeed, travelers in the active commitment condition made substantially more sustainable choices than those in the passive commitment condition, whereas those in latter condition did not make significantly more sustainable choices than participants in the control condition. Further, some of the obtained effect sizes were considerably greater than the typical effect sizes in consumer research, marketing, and psychological science, thus implying that our findings should be highly practically relevant (Funder & Ozer, 2019). However, we have yet to demonstrate the psychological mechanism behind our focal effect. Moreover, it remains to be examined how generalizable the results from Study 2 are. Accordingly, we address these points in Studies 2A-B.
Study 2A: Extension and Mediation
Study 2A sought to extend our initial findings by (1) replicating our focal effect (as per
Participants were randomly allocated to one of the four experimental conditions, with scenarios mirroring those used in Study 1 for active and passive commitment. However, to also manipulate which message participants received, some were provided with specific information about the airport coffee shop, while others were instead provided with more generic information. More precisely, the information on the sign that stated the coffee shop’s environmental commitment was manipulated, with the text outside the brackets representing the specific conditions and the text inside the brackets representing the generic conditions: We have long been a steward of the environment. At this specific coffee shop [At our coffee shops around the globe], we have a number of efforts in place to care for our planet, ranging from water and energy conservation and recycling to eco-conscious options for the guests of this very airport [airports throughout the entire world].
Having read their assigned scenario and, for participants in the active commitment conditions, having decided whether to practice environmentally friendly behavior (yes vs. no), all participants then made the same binary choice between a disposable to-go-cup or a reusable cup of porcelain, which served as our main dependent variable.
To test our proposed psychological mechanism of consistency effort, participants also indicated on a 9-point scale the extent to which they agreed with the statement, “I make an effort to appear consistent to others” (1 = strongly disagree; 9 = strongly agree; Nichols & Webster, 2014). Such single-item measures are valid if they capture clear and unambiguous constructs (Bergkvist & Rossiter, 2007), as in the current case. Moreover, to examine potential spillover effects of our commitment manipulation on other sustainable responses, participants indicated their agreement on seven items that measured other “green” actions in an airport travel context using the same 9-point response format (e.g., order vegan or vegetarian dishes at airport restaurants to limit agriculture greenhouse gas emissions; reuse towels in your next airport hotel room to conserve water and electricity). These items were author-constructed but closely mimicked similar measures used in previous related research (e.g., Goldstein et al., 2008; Otterbring & Folwarczny, 2024). We averaged all seven items into a composite index of “green” airport actions (Cronbach’s α = .69).
Participants also replied to the same social desirability scale used in Study 1 (Cronbach’s α = .72). Finally, at the end of the experiment, they completed two binary manipulation checks related to whether their assigned condition (1) asked them to actively commit to practicing environmentally friendly behavior (yes vs. no), and (2) included specific or generic information about the coffee shop (specific vs. generic).
Results
Choice Behavior
Message type did not influence participants’ sustainable choice likelihood and did not interact with commitment; see the Supplemental Materials for details. Therefore, we performed a Pearson’s chi-square analysis using 2 (commitment condition: active vs. passive) × 2 (cup choice: unsustainable vs. sustainable) crosstabs. This analysis found a significant association effect, χ2(1, N = 1,050) = 30.22, p < .001, V = 0.17, with this finding approaching a moderate effect size despite the conservative approach of only comparing the two conditions that differed the least in Study 1 (i.e., active vs. passive commitment instead of active commitment vs. control). In line with
Mediation
To test
Discussion
Study 2A replicates and extends the findings from Study 1 by documenting that several distinct settings in which active commitment is implemented increase travelers’ sustainable choice likelihood and their willingness to perform other “green” actions. As such, we document that our focal effect is externally valid and hence generalizes across a variety of contexts, as called for by several scholars (e.g., Fabrigar et al., 2020; Otterbring & Folwarczny, 2024). This is notable, as we deliberately relied on a severe testing approach (Mayo, 2018) by only comparing the two conditions that differed the least in our initial study, making it more difficult to find differences between conditions. Despite this conservative approach, the obtained effect size on our focal choice-based outcome still translated to an effect comparable to the typical effect sizes in the published literature in consumer behavior, marketing, and psychology, with such effects frequently described as carrying important practical implications (Funder & Ozer, 2019). In addition, we provide empirical evidence for the notion that travelers’ consistency effort acts as a psychological mechanism driving our active commitment effect. As in Study 1, these results are robust to the inclusion of a theoretically relevant control variable (social desirability), ensuring that our studied causal chain applies in study designs with high rigor, control, and internal validity. However, it remains to be examined whether our internal focus on active personal commitment interacts with external social norms to shape travelers’ sustainability-oriented responses. This possibility is particularly relevant to address given that a manifestation of social norms represents another influential social influence principle. Specifically, social proof messages that communicate how most others behave in a certain situation (e.g., “75% of other travelers act sustainably”) have been shown to effectively influence human judgment and decision-making in a way mirroring such majority-based messages, because people often assume that others’ behavior serves as a valid cue to what is desirable and normatively the right thing to do (Cialdini & Goldstein, 2004).
Study 2B: Active Commitment and Social Proof
The primary purpose of Study 2B was to further test the replicability and generalizability of
Participants were randomly assigned to one of the four experimental conditions, with scenarios mirroring those used in Study 1 for the active commitment and control conditions. However, to also manipulate social proof, some were provided with a majority-based message acting as descriptive social norms of how most others behave at the airport coffee shop. As such, some participants received the additional information that, “75% of our current customers make sustainable choices at our coffee shop. This large proportion likely reflects that most people believe acting sustainably is the right thing to do.” The scenario closely mimicked other social proof manipulations used in existing research (Goldstein et al., 2008; Loschelder et al., 2019; Otterbring & Folwarczny, 2024).
Next, participants made the same binary choice between a disposable to-go-cup or a reusable cup of porcelain as our focal dependent variable, after which they replied to the consistency effort item from Study 2A using the same 9-point scale format. The study concluded with participants replying to two binary manipulation checks, which focused on whether their assigned condition (1) asked them to actively commit to practicing environmentally friendly behavior (yes vs. no), and (2) stated that 75% of the coffee shop’s current customers make sustainable choices (yes vs. no).
Results
Choice Behavior
Social proof interacted with commitment to influence participants’ choice behavior; see the Supplemental Materials for details. Therefore, to decompose the interaction, we ran separate chi-square analyses with and without social proof. These analyses showed a moderate-to-large effect size in the presence (vs. absence) of active commitment without social proof, χ2(1, N = 392) = 21.57, p < .001, V = 0.24. Thus, the majority of participants (67.3%) in the active commitment conditions selected the sustainable option, whereas only a minority (44.0%) did so otherwise. However, with social proof, the presence (vs. absence) of active commitment yielded a non-significant and negligible effect, χ2(1, N = 390) = 1.38, p = .240, V = 0.06. Here, most travelers selected the sustainable option both with (69.5%) and without (63.9%) active commitment. Thus, active commitment was sufficient to significantly boost travelers’ sustainable choice behavior, and adding social proof did not further increase effectiveness.
Mediation
To test
Discussion
Study 2B further underscores the robustness, replicability, and generality of active commitment when it comes to steering travelers in a sustainable direction. It also provides additional empirical evidence for the psychological mechanism responsible for this effect by means of travelers’ greater consistency effort under conditions of active commitment. Although both active commitment and social proof separately increased travelers’ inclination to choose sustainably, adding social proof to active commitment did not further increase effectiveness. Further, the effect size of active commitment was greater than the effect size of social proof. Together, these results support
Study 3: Testing the Entire Moderated Mediation Model
In our final study, we sought to test whether the main effect of active commitment on travelers’ choice likelihood of sustainable options would be moderated by the travelers’ cultural belonging, such that the effects hitherto demonstrated are stronger in individualistic (vs. collectivist) cultures (
Participants were randomly allocated to one of the experimental conditions (active commitment vs. control), with scenarios that mirrored those used in Study 1 for active commitment and control. We prescreened participants such that we only included people whose stated ethnicity was White as individualistic, whereas only people whose stated ethnicity was Asian were categorized as collectivist. While cultural identity is fluid and shaped by multiple factors, we used ethnicity as a proxy for individualism (vs. collectivism) for pragmatic reasons. Although this approach has certain limitations, it remains a widely accepted method in cross-cultural research when direct measurement of cultural orientation is not feasible (Markus & Kitayama, 1991; Taras et al., 2010). Extensive meta-analyses have demonstrated that ethnic groups tend to exhibit consistent cultural tendencies in terms of individualism-collectivism. For example, research has repeatedly shown that Western European and North American populations score significantly higher on individualism, whereas East Asian, South Asian, and Latin American populations score higher on collectivism (Oyserman et al., 2002; Triandis, 2018). These findings provide strong justification for using ethnicity as a grouping variable in experimental research. Furthermore, given the large sample size required for the current study, directly measuring individualism-collectivism through validated psychometric scales (e.g., Triandis & Gelfand, 1998) would have added considerable time, complexity, and potential survey fatigue. In addition, self-reported cultural orientation measures have been shown to exhibit a considerable degree of overlap with country-level proxies for individualism-collectivism in prior work on the commitment-and-consistency principle (Cialdini et al., 1999).
Having read their assigned scenario and, for participants in the active commitment conditions, having decided whether to practice environmentally friendly behavior at the described coffee shop (yes vs. no), all participants made the same binary choice between a disposable to-go-cup or a reusable cup of porcelain, which yet again served as our main dependent variable. Participants also indicated, on the same 9-point scale used in Study 2, the extent to which they agreed with the statement, “I make an effort to appear consistent to others” (1 = strongly disagree; 9 = strongly agree), which served as our mediator. Moreover, they replied to the same seven items measuring their willingness to exhibit other “green” actions in an airport travel context using the same scale format as in Study 2. These items were averaged to create a composite index of “green” airport actions (Cronbach’s α = .70). Finally, participants replied to the same manipulation check item used in Study 1, which asked whether their assigned scenario stated something about the coffee shop’s commitment to the environment (yes vs. no).
Results
Choice Behavior
Culture interacted with commitment to influence participants’ choice behavior; see the Supplemental Materials for details. Therefore, to decompose the interaction, we ran separate chi-square analyses for individualistic and collectivist participants using 2 (commitment condition: active vs. control) ×2 (cup choice: sustainable vs. unsustainable) crosstabs. These analyses found the same significant effect across cultures, but with the effect size being considerably larger in the individualistic sample (χ2(1, N = 382) = 37.71, p < .001, V = 0.31; active commitment: 77.4% sustainable choices vs. control: 46.9% sustainable choices) relative to the collectivist sample (χ2(1, N = 373) = 8.96, p = .003, V = 0.16; active commitment: 61.5% sustainable choices vs. control: 46.1% sustainable choices). In fact, the key comparison for the individualistic sample corresponds to a large effect size, whereas the same comparison only yields a small-to-moderate effect size for the collectivist sample about half the size of the effect for the individualistic sample.
Moderated Mediation
To test our entire chain of events, we conducted two moderated mediation analyses (PROCESS Model 8; Hayes, 2017), in which commitment condition (passive = 0; active = 1) served as the predictor, participants’ consistency effort (continuous) acted as the mediator, and culture (collectivist = 0; individualistic = 1) served as the moderator. In our primary analysis, participants’ cup choice (unsustainable = 0; sustainable = 1) served as our focal outcome. As a supplementary analysis, participants’ willingness to exhibit other “green” airport actions served as our secondary outcome.
Regarding our primary analysis, the index of moderated mediation was statistically significant, as evidenced by the 95% [CI] that did not contain zero (95% CI [0.02, 0.26]), thus supporting
For our secondary analysis, the index of moderated mediation was yet again significant (95% CI [0.01, 0.19]). Mirroring the primary analysis, the indirect effect of experimental condition on the inclination to exhibit other “green” airport actions through participants’ consistency effort was significant and positive among individualistic participants (β = .15, 95% CI [0.08, 0.23]), thus replicating the findings from Study 2. In other words, individualistic participants in the active commitment (vs. control) condition were more inclined to score high on the “green” airport actions index because this condition boosted their consistency effort. By contrast, the indirect effect of experimental condition on the inclination to exhibit “green” airport actions through participants’ consistency effort was non-significant among collectivist participants (β = .05, 95% CI [−0.005, 0.11]). Again, however, this latter indirect effect was significant when using 90% CI (b = 0.05, 90% CI [0.01, 0.11]), suggesting that active commitment prompted “greener” airport actions through increased consistency effort also among collectivist participants, albeit to a weaker extent than the effect for individualistic participants.
Finally, to further demonstrate robustness of our main findings and counter concerns regarding our proxy variable of individualism and collectivism, we performed additional analyses on a constrained sample comprising (1) people who categorized themselves as White and who were simultaneously born in an English-speaking country or (2) people who categorized themselves as Asian and who were simultaneously born in an Asian country (N = 535; 71% of the sample used in our main analyses). This classification aligns with recent research (Gómez-Corona & Otterbring, 2025), in which people from English-speaking Western, educated, industrialized, rich, and democratic (WEIRD; Henrich et al., 2010) countries are frequently compared with people from other world regions, such as Asia. The hypothesized results also emerged in this more conservative analytic approach, despite the smaller sample size; see the Supplemental Materials for details.
Discussion
Study 3 replicates the main effect of active commitment on travelers’ choice likelihood of sustainable options as well as their greater consistency effort under such circumstances. However, these effects are contingent on the travelers’ cultural belongings, such that the effect of active commitment (vs. control) on choice likelihood of sustainable options is stronger among those from individualistic (vs. collectivist) cultures, with a large effect size tied to clear practical relevance for travelers from individualistic cultures and a more modest and but still ultimately consequential effect size for travelers from collectivist cultures (Funder & Ozer, 2019). As such, culture emerges as an important boundary condition for our focal effect. Most central for Study 3, our proposed moderated mediation model received empirical support not only in our primary analysis focused on travelers’ choice likelihood of a sustainable option but also in our secondary analysis regarding their inclination to exhibit additional “green” airport actions. Thus, although travelers across both individualistic and collectivist cultures indicated higher consistency effort, made more sustainable choices, and were more inclined to exhibit other “green” airport actions in the active commitment condition relative to the control condition, the links between active commitment and (a) choice likelihood of a sustainable option and (b) willingness to perform other “green” airport actions were only robustly mediated by higher consistency effort among travelers from individualistic but not collectivist cultures.
General Discussion
Across four experimental studies and a total sample of over 3,000 travelers, we find consistent support for the role of active commitment in influencing travelers’ likelihood of making sustainable choices. Study 1 revealed that participants who actively commit to practicing environmentally friendly behavior at an airport coffee shop show a markedly higher propensity to make sustainable choices compared to those in a passive commitment condition and a control condition. Studies 2A-B then documented that the active commitment effect is mediated by travelers’ consistency efforts. In other words, by actively committing to practicing environmentally friendly behavior, travelers’ effort to be consistent increases, ultimately resulting in a greater likelihood of making sustainable choices. Study 3 introduced travelers’ cultural belonging as a theoretically meaningful moderator, illustrating that the effectiveness of active commitment is more pronounced for individuals from individualistic rather than collectivist cultures, thus explaining why active (vs. no) commitment carries stronger downstream effects on individualistic travelers’ consistency effort and sustainable choice likelihood. Notably, this final study verified our proposed moderated mediation model linking active commitment to an interplay between travelers’ consistency effort, cultural belonging, and their likelihood of making sustainable choices as well as their willingness to exhibit other “green” airport actions, offering a holistic understanding of the cultural boundaries in our proposed chain of events; see Table 1 for an overview of the results obtained across studies.
Study Findings.
Contributions to Theory
The results reported herein contribute theoretically in four distinct ways. First, we advance research on the commitment-and-consistency principle by extending its applicability to high-stakes, transient service environments in studies with large sample sizes and high statistical power, showcasing a considerable generalizability of active commitment across message types, outcomes, and study paradigms. Prior related research has primarily examined habit formation in commercial settings (e.g., sales and marketing; Burger, 1999) or goal-driven contexts (e.g., health and financial behaviors; Gollwitzer, 1999). However, such studies largely assume that individuals have time for repeated exposure to commitment interventions, allowing consistency to emerge gradually over time. Our work challenges this assumption by demonstrating that even in highly transient settings such as airports, a single commitment act can significantly influence sustainable behavior among travelers. This finding underscores the robustness of commitment effects beyond commonly investigated settings, showing that one-time interventions can effectively lead to desirable behavior change also in these travel environments.
Second, this research differentiates between active and passive commitment, offering novel insights into why active commitment is superior in driving behavior change. Our findings demonstrate that active commitment—where individuals explicitly affirm their pro-environmental stance—results in significantly stronger behavioral adherence than passive commitment, where individuals just acknowledge the presence of certain sustainability cues. As such, travelers need to be active agents rather than passive patients for behavior change to occur. This is probably particularly pertinent in settings where external distractions and time pressure may otherwise weaken commitment adherence, such as in airports.
Third, we identify travelers’ consistency effort as a key driver of sustainable choices and the inclination to exhibit other “green” airport actions, offering a deeper understanding of the psychological mechanism explaining why active commitment interventions work. Prior theoretical explanations for commitment-based interventions have often attributed their effectiveness to cognitive dissonance reduction, although such attributions have rarely been tested in empirical research (Harmon-Jones & Harmon-Jones, 2008; Proulx, 2012; Randles et al., 2015). According to such largely untested conceptualizations, individuals align their behavior with prior commitments to maintain internal consistency. Our research adds to this perspective by identifying consistency effort—an individual’s cognitive effort to uphold their commitment—as the driving force behind commitment-induced behavior change. Rather than merely adjusting attitudes to reduce dissonance, individuals exert effort to maintain their commitments, making them more likely to engage in sustainable behavior. This insight refines the psychological understanding of commitment-based interventions by demonstrating that it is not just the presence of commitment, but the effort invested in maintaining it, that determines behavioral change.
Fourth, the introduction of cultural orientation as a theoretically relevant boundary condition advances conceptualizations regarding the applicability of the commitment-and-consistency principle across cultures, thereby painting a more complete picture of when and under what circumstances our theorizing holds. The fact that this principle is more influential among travelers from individualistic rather than collectivist cultures suggests that cultural factors need to be considered when designing interventions aimed at promoting sustainable choices and similar responses.
In sum, this research contributes to the existing body of knowledge by (1) establishing the generalizability of the commitment-and-consistency principle in guiding sustainable airport actions, (2) clearly showcasing the superiority of active, as opposed to passive, commitment, (3) unraveling the psychological mechanism driving our focal effect, and (4) recognizing contextual sensitivity in the effectiveness of active commitment from a travel-related sustainability perspective, by documenting travelers’ cultural orientation (individualistic vs. collectivist) as a meaningful moderator.
Managerial Implications
The current findings offer actionable insights for airport managers, environmental NGOs, policymakers, and sustainability-focused businesses. First, the generalizable impact of active commitment across diverse samples and settings suggests that the implementation of the commitment-and-consistency principle in travel contexts can be a powerful tool for encouraging sustainable choices. Accordingly, practitioners can design interventions that leverage active commitment, ensuring they are adaptable to various environmental circumstances. Doing so appears to increase travelers’ general choice likelihood of sustainable options by approximately 50% to 75% when compared with the existing (no commitment) status quo according to our findings.
Beyond eliciting active commitment, reinforcement mechanisms must be strategically deployed to sustain travelers’ consistency effort. This can be accomplished through digital feedback loops, periodic reminders, and incentive structures that encourage travelers to uphold their commitments over time. For instance, airport mobile applications and digital signage can display real-time updates on collective sustainability efforts, potentially combined with social proof messages, such as “50,000 travelers this month have chosen reusable cups—join the movement!” Personalized messaging, based on prior consumption behaviors, can further strengthen consistency effort, as seen in AI-driven app notifications reminding travelers of their past sustainable choices, which can be leveraged to ensure continued efforts in sticking to one’s commitments. The use of gamification elements, such as sustainability leaderboards or recognition-based rewards, can also incentivize repeat engagement with sustainability-oriented actions.
At the policy level, airport authorities and managers should integrate sustainability nudges as part of their communication with travelers, ensuring that commitment-based prompts are embedded within various service touchpoints. Considering the verified effectiveness of defaults according to field experiments and meta-analytic evidence (Hansen et al., 2021; Jachimowicz et al., 2019; Mertens et al., 2022), moving toward default opt-in models for sustainable choices, such as making reusable cups the salient standard with an opt-out feature for disposable alternatives, can leverage the commitment-and-consistency principle while maintaining consumer autonomy.
Given the observed cultural moderation effects, commitment-based interventions should also be customized to align with travelers’ cultural orientation, values, and norms. Our findings imply that travelers from individualistic cultures may respond more favorably to identity-signaling messages (e.g., “Make a choice that reflects your personal values”), whereas their counterparts from collectivist cultures may rather be influenced by group-based messages (e.g., “Join others in making a sustainable impact”). To ensure global applicability, commitment messages should be tailored across different cultural segments through geotargeted content, multilingual digital prompts, and adaptive message framing. A/B testing of different commitment strategies across diverse demographics can further refine these interventions, ensuring maximum effectiveness in international airport settings.
Limitations and Future Research
The current research has certain limitations that can serve as future research directions. For instance, our empirical focus on airports limits the generalizability of our findings to other travel contexts. Travelers’ decision-making differs significantly across contexts, and factors such as consumer engagement duration, frequency of interactions, situational constraints (e.g., time, money, etc.), and external incentives may influence commitment effectiveness. While airports represent transient environments where travelers make quick, convenience-driven choices, other sectors—such as hospitality, retail, and public transportation—involve different psychological and structural conditions that might differentially shape the effectiveness of commitment-based interventions. Therefore, future research will benefit from carrying out cross-sector comparisons to shed light on the specific conditions and service settings in which commitment-based interventions are particularly effectively. If commitment interventions prove more effective in sectors with habitual consumer engagement (e.g., retail, hospitality) but less so in one-time settings like airports, this would imply that commitment effects sometimes require reinforcement through repeated interactions. Conversely, if interventions are effective even in highly transient sectors like public transport, this would indicate a broader applicability of the commitment-and-consistency principle across settings and sectors.
Given that active commitment was examined in typical one-time travel contexts herein (e.g., people going on a vacation trip with the airport and flight acting as a bridge between their everyday life and an exotic vacation), future sustainability strategies should explore whether the current findings generalize to other service environments. The transient nature of airports implies that the effectiveness of commitment interventions might well work differently here compared to, for instance, settings that consumers visit more regularly (e.g., hotels, retail stores, or urban transportation systems). Practitioners should consider sector-specific factors, such as decision urgency, economic trade-offs, and social influence dynamics, when designing interventions beyond airport settings. By leveraging these insights, industry leaders can craft more effective sustainability initiatives, embedding commitment strategies into consumer decision-making processes and driving long-term behavioral change across service contexts.
The use of a single-item measure for the psychological mechanism assumed to drive our focal effect might introduce measurement issues. Although we relied on a doubly-concrete construct when measuring travelers’ consistency effort, with such clear and unambiguous single-item measures being at least as valid as multi-item scales (Ang & Eisend, 2018; Wanous et al., 1997), we acknowledge that the opinions diverge regarding the appropriateness of such single-item measures (Diamantopoulos et al., 2012; Sarstedt et al., 2016). Future studies might benefit from more robust and multifaceted measurement approaches to capture the complexity of our studied constructs, such as the preference for consistency scale (Cialdini et al., 1995).
As the main goal of the current research was to isolate effects and, hence, test the causal relationship between active commitment and travelers’ likelihood of making sustainable choices, we sought to maximize internal validity while sacrificing a certain level of ecological validity. Indeed, one of the main ideas behind controlled experimental studies like ours is that such studies enable scholars to draw causal inferences. If the main objective is to test theory, as in the case of the current research, powerful manipulations are crucial, as they increase the probability that an experimental manipulation is strong enough to exert an influence on the key variables of interest. Weak effects on a manipulation check typically makes it much more difficult and many times impossible to show that a manipulation had a causal impact on one’s key variables. As such, we followed best practices in experimental research, as further underscored by our measurement of several potential confounding factors, such as social desirability, and blinding participants to the specific purpose of the current studies, although all participants received a generic study description at the outset of each study. That said, we willingly acknowledge that our studies are not equally strong in terms of their ecological validity. Although we were cautious in not overselling our findings, our hypothetical choice paradigm means that data on travelers’ naturalistic choice behavior are needed before our results have been fully verified in real-world contexts (Baumeister et al., 2007; Gidlöf et al., 2021), preferably collected in actual field settings (e.g., real airports). Therefore, while our selected study approach maximized measurement, statistical conclusion, and internal validity, future research would benefit from trying our experimental setup in actual field settings to further test the robustness, replicability, and generalizability of our obtained results.
Another limitation is our binary classification of cultural orientation. While this approach aligns with established cross-cultural research practices, it does not fully capture the complexity and fluidity of cultural identities, particularly in an increasingly globalized world where hybrid cultural influences are common (Taras et al., 2010). That said, self-reported cultural orientation measures of individualism and collectivism—as captured at the individual level—have been shown to yield virtually identical results as comparable nation-level categories of individualistic and collectivist countries in previous research on the commitment-and-consistency principle (Cialdini et al., 1999). Nevertheless, future research might still get a more fine-grained understanding of our tested relationships if individualism and collectivism is measured at the level of individual travelers instead of categorizing them based on their cultural belonging. Furthermore, our work implicitly assumes that people from collectivist cultures prioritize externally oriented group harmony over internally oriented consistency. However, there may still be certain contexts where commitment strengthens consistency effort rather than diminishes it among collectivist individuals. For instance, prior research suggests that people from collectivist cultures may exhibit stronger behavioral adherence when a commitment is framed as a group-driven responsibility rather than as a personal pledge (Triandis, 2018). As such, future research should explore how commitment-based interventions function when aligned with socially embedded obligations in collectivist cultures.
We measured and controlled for social desirability bias across Study 1 and Study 2A, finding that social desirability was linked to a slightly greater likelihood of choosing the sustainable option, although this effect was small by conventional standards and much weaker than the effect of active commitment on participants’ choice behavior. More importantly, our active commitment results remained unchanged even after controlling for social desirability. Further, we did not measure social desirability in Study 2B and Study 3 but still replicated our focal active commitment effect, implying that our results hold irrespective of whether participants read about and replied to questions regarding social desirability. Of course, these results do not preclude the possibility that certain social desirability issues are still at play in our studies. Nevertheless, we admittedly did much more than most other studies to control for various bias sources, including social desirability.
Finally, the focus on immediate outcomes leaves a gap in understanding the long-term effects of active commitment strategies on travelers’ likelihood of making sustainable choices. Future research could investigate the sustainability of our observed effects over more extended periods, providing insights into the enduring impact of commitment interventions.
Supplemental Material
sj-docx-1-jtr-10.1177_00472875251346930 – Supplemental material for Activating Green Airport Actions: Promoting Eco-Friendly Choices for Sustainable Travel Through Commitment and Consistency
Supplemental material, sj-docx-1-jtr-10.1177_00472875251346930 for Activating Green Airport Actions: Promoting Eco-Friendly Choices for Sustainable Travel Through Commitment and Consistency by Tobias Otterbring, Suresh Malodia, Babak Taheri and Amandeep Dhir in Journal of Travel Research
Footnotes
Author Contributions
Tobias Otterbring: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Validation, Visualization, Writing - original draft, Writing—review & editing. Suresh Malodia: Conceptualization, Data curation, Investigation, Resources, Visualization, Writing—original draft, Writing—review & editing. Babak Taheri: Resources, Writing—review & editing. Amandeep Dhir: Conceptualization, Investigation, Resources, Writing—review & editing.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
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