While interviews are commonly used in social research, the methodology carries its own important procedural and ethical implications. Inequitable power relations are unavoidable in academic research where the interaction is primarily directed by the researcher (King et al., 2018). Interactional identities are compounded by factors such as gender, ethnicity, socioeconomic status and education, which may be overt or covert (Anyan, 2013). Cultural assumptions imposed through interview protocols, questioning and instrumentation can potentially cause offense and discomfort to participants situated in other cultures; such inequitable dynamics can also diminish the value of the information obtained (Brinkmann and Kvale, 2008). It is critical that cross-cultural research teams consider ethical issues not only in terms of the interview interaction itself, but to procedural issues prior to the interview interaction (including protocol design, question wording and recruitment), and ongoing reflections following the interview (including analysis, reporting findings and dissemination of research) (Hoover et al., 2018).

In designing the interview protocol, we worked closely with in-country collaborators to ensure not only that the protocol and question wording were designed to elicit the topics in which we were interested, but to address issues of culturally imposed bias (such as making assumptions about environmental conditions, values and lifestyle practices of those within a given culture). All interview materials were double-translated into the local language(s). For balance and to reduce potential cultural and gender imbalance that might otherwise constrain trust and disclosure, particularly for female participants (Campbell and Wasco, 2000; Sikes, 2018), the interview team comprised the same male researcher (lead author) and a different female translator in each country. The female translator played an active part in the interaction as opposed to simply translating questions and responses, introducing additional questions, checking understanding and elaborating on culturally relevant issues for clarification. Having a cultural “insider” as part of the team helped facilitate trust and disclosure, while the presence of a cultural “outsider” generated greater insight into the participant’s world by rendering the familiar strange (Dwyer and Buckle, 2009). The presence of a researcher from another culture also occasionally led to a richer exploration of perspectives linked to economic globalization, resource inequities and sources of environmental harms beyond geographical borders. While a translator was present, some participants expressed a willingness to conduct interviews in English or switched between English and their native language (for example, if they were unable to explain a point in English). We acknowledge that translation imposes an additional level of interpretation on an utterance (Caretta, 2015), therefore we have tried insofar as possible, to analyze accounts based on participants’ direct speech rather than the translator’s interpretation.

As mentioned, for practical reasons it was not always possible to interview participants at the collaborating institutions. In such cases we took the pragmatic decision to stage interviews in other locations, such as workplaces and homes. In doing so, we acknowledge that space and place are active and influential factors in negotiation interactions between researcher and research participant (Gagnon et al., 2015). Before conducting an interview in an alternative location, we ensured that spaces were available in which participants could discuss issues confidentially without being in the direct gaze of, overheard by, or interrupted by others. We also applied this rubric to interviews that took place in collaborating academic institutions. Allowing participants greater flexibility to choose their preferred location also served to engender a more equitable relationship with participants (Gagnon et al., 2015). We noted that when conducting interviews in participants’ homes, the home itself sometimes served as an exemplar of lifestyle discussions in which participants illustrated their accounts with reference to their home interiors, gardens and wider surroundings. We also noted that in workplace interviews, participants sometimes referred to documents and other office procedures or apparatus (such as air conditioning systems or office recycling systems), in discussions. This enriched fieldnote records and would not have been possible if held in more neutral academic institutions.

Written, informed consent (in the local language) was sought from all participants prior to interview. Interviews took approximately 1–1.5 h to complete, in which the interview team covered a set protocol of basic questions in all three countries for meaningful comparison, but also allowing for follow-up questions and the exploration of issues that were more culturally specific to each country. Therefore, the flexibility of the semi-structured interview method was advantageous in that it could be applied to multisited cross-cultural contexts (Hagaman and Wutich, 2017), as well as allowing the generation of more detailed, culturally specific context (McIntosh and Morse, 2015). At the end of each interview, participants were provided with a verbal and written debrief (in the local language), along with researcher contact details in case of further questions.

An episodic narrative approach was used to explore participants’ lifestyles, which seeks to ground perceptions and experiences as lived narratives within the wider society and culture (Flick, 2000; Jovchelovitch and Bauer, 2000). The episodic interview method is a form of narrative interviewing that elicits snapshot descriptions of particular episodes or features in a person’s life as a way of making sense of the world. The questions in the interview protocol sought to contextualize accounts rather than to generate more abstract responses, as this risked neglecting wider socioculturally relevant issues. The preset interview question list appears in Supplementary Appendix A. While the protocol explored a range of environmentally salient issues, this paper is primarily focused on responses elicited by the question, “Can you remember in the past whether doing something that was good for the environment caused you to then do another environmentally-friendly behavior?,” though we looked for examples of spillover throughout each transcript.

Interviews were audio-recorded and subsequently translated and transcribed. Written field notes were also recorded throughout the interaction. An “in-interview” system of translation was employed in which questions and responses were translated to and from English by the translator (except where participants preferred to speak in English). Another layer of translation was imposed at the transcription stage. In the analysis section, quotes are labeled “Direct” if spoken in English, or “Transl.” if translated from another language (either by the translator in the interview or during transcription). The interview audio and texts were analyzed using NVivo 11, supplemented by written field notes. We then used a system of template analysis to code the texts, as template analysis is particularly suited to identifying themes in both essentialist and constructionist analyses (Brooks et al., 2015).

To address our first research question we aggregated and compared responses to the question of whether spillover had ever occurred, across countries. Table 2 summarizes the proportions of participants who were directly questioned about spillover (some were not asked due to time constraints) and the proportions of those recalling and not recalling spillover. As discussed in the previous section, accounts of spillover did not emerge spontaneously from the interviews. The majority of participants were directly questioned about spillover. Among those who were directly asked, exactly half recalled an experience they considered to be analogous to spillover.

Table 3 breaks down reports positive spillover effects into discrete categorizations based on the academic literature. Overall, the most commonly reported type of spillover effects reported were within behavioral domains (i.e., between behaviors within the same cluster). The second most commonly reported effects were those that did not fall within conventional academic definitions of spillover. The category refers to responses citing other behavioral motivations (for example, formative experiences when young, changes in personal circumstances and other experiences) as catalysts, rather than engagement in a specific behavior. A range of other spillover effects were also found but these were less commonly reported than within-domain effects. These included contextual, interpersonal and between-domain spillover effects. Finally, 4 reports of positive behavioral spillover were unclear in terms of the behaviors involved and were counted separately.

We found both differences and similarities in reports of spillover across cultures. Table 2 shows that in Brazil and China the majority of participants were directly questioned about spillover, while all participants in Denmark were directly questioned. Of these, over half of participants in China and Brazil recalled having experienced positive spillover, though less than half of Danish participants recollected spillover having happened to them. The largest proportion of spillover accounts came from China and the smallest came from Denmark.

Table 3 shows that despite the differences in sample sizes and the proportions of participants directly questioned about spillover, frequencies of recollections of within-domain spillover in each country were almost identical. Within-domain spillover effects were the most commonly reported categories in China and Denmark while in Brazil the most common type of account related to “other” motivations. Recollections of between-domain spillover were so infrequent that meaningful cultural comparisons cannot be drawn, other than to say that catalytic effects from one behavioral cluster to another were extremely rare in all three countries. Similarly, reports of other spillover effects were too uncommon to infer cultural differences. However, contextual spillovers were more frequently reported in China than in Brazil and Denmark, while interpersonal spillover effects were only reported in Brazil. In addition, while Chinese participants did not report other behavioral motivations as spillover effects, those in Brazil and Denmark reported the same numbers of accounts in which behavior was catalyzed by non-behaviors. More detailed discussion of the different types of spillover and further examples of cultural differences, along with quotes can be found in the section on “Personal Accounts of Different Types of Positive Spillover Effects”.

As shown in Table 2, accounts of behavioral spillover were far more common among environmentally engaged participants than those who were less engaged, regardless of cultural context. For both more and less engaged groups, the majority were directly questioned about spillover. Of those questioned, the highest proportion of accounts of spillover effects came from more engaged participants in China, followed by their counterparts in Brazil and Denmark, respectively. With reference to those less environmentally engaged, fewer accounts emerged from Danish participants than those in Brazil and China.

Between-domain spillovers were reported mainly by more environmentally engaged groups, while the rare examples of between-domain spillover came exclusively from the more engaged groups (in China and Denmark). All but one example of contextual spillover came from more engaged groups; similarly, all examples of interpersonal spillover came from the more engaged group in Brazil (Table 3). Of course, while the pathways to spillover bore some similarity across cultures, these accounts were also grounded within their specific cultural contexts. We now move on to discuss accounts of behavioral spillover effects in more detail.

Reports of positive spillover in the interviews emerged from participants in all three countries studied. Where spillover effects were reported, they most commonly involved relationships between two related actions, or an increase in the frequency or range of a single behavior. Behaviors reported in accounts of spillover in the interviews were mainly in the private sphere and drew on a limited range of behavioral clusters. In all three countries, spillover relationships principally drew on clusters comprising waste (for example, littering, recycling and composting) and resource conservation (such as reducing energy or water use) practices practiced domestically. In Denmark, in addition to waste and resource conservation, some participants also referred to spillovers involving organic consumption and the occasional public-sphere action, such as volunteering for an environmental organization or community litter-pick (see below). These spillover effects typically involved an extension of the initial behavior, such as buying more organic products, reusing more items or picking up litter elsewhere, as opposed to catalyzing different behaviors. The following extract gives a flavor of within-domain spillover from Brazil. In the account the participant describes how consciously reflecting on existing efforts to limit paper towel use was attributed to a motivation to subsequently reduce paper waste by storing documents on the computer rather than printing them:

In reflecting on the shift from saving paper towels to avoiding printing on the computer, the speaker explains that the initial behavior was personally important. The account also suggests that the initial behavior was consciously (as opposed to habitually) performed, which is used to explain the process by which they came to adopt a new behavior with the same goal. Stating that it was possible to use an alternative form of storage (i.e., storing documents on the computer rather than as hard copies), suggests that aligning behavior consistently depends to some degree on the availability of viable alternatives in switching to more sustainable practices.

As mentioned above, in addition to the adoption of a new behavior, within-domain spillover effects not only involved situations where engaging in one action catalyzed another discrete behavior within the same cluster, but also an increase in the frequency or range of an existing behavior over time. In the next extract from Denmark, the speaker talks about organic shopping practices and a spillover effect in which organic consumption had expanded over time to include an increasing array of products:

Like the previous account, the speaker constructs organic purchasing as a conscious and deliberate activity that centers on a personally salient goal. Accounting for the spillover effect relies on both awareness and the increasing availability of viable organic alternatives to conventional products.

In addition to reports of spillover effects from one behavior to another within the same cluster, examples emerged where performing a behavior catalyzed the motivation to engage with others and discuss environmental issues or encourage other people to engage in actions with the same goal. However, such examples were limited and came only from participants in Brazil and China and only from the more environmentally engaged groups in those countries. In the following example from Brazil, the speaker explains how engaging in a collection of unspecified pro-environmental actions had led them to engage more with others:

Within the above account, in discussing engaging others on environmental issues, the speaker stresses that they do not wish to instruct other people, but to gain an insight into why other people are less conscious in reflecting on the environmental relevance of their behavioral decision-making. This is linked to a concern that trying to teach others will drive them away from the issue rather than draw them in. We highlight this type of example because this type of spillover effect offers significant potential as a means of generating wider engagement beyond that of the adoption of one behavior on the strength of another, for a single given individual. We now move on to discuss some rarer examples of behavioral spillover between different behavioral clusters.

If behavioral spillover generates wider lifestyle shifts through spreading activation, one might expect to observe catalytic effects between environmentally responsible actions in different behavioral clusters. However, only a couple of examples of between-domain spillover were recorded in the interviews. Both came from more environmentally engaged participants in China and Denmark (see Table 3). In the first extract from Shanghai, the speaker explains how walking catalyzed the motivation to increase consumption of vegetables; though both actions were driven not by pro-environmental goals, but by goals linked to health outcomes:

In trying to become a healthier person, engagement in an initial action aligned with a personally salient goal is constructed as generating a greater conscious awareness of other health-related actions while engaged in that behavior. This, in turn, motivated the intention to make dietary changes. In addition, toward the end the speaker explains that progress toward the desired goal (becoming healthier) increases motivations to think about doing more (exercise). The extract shows how pro-environmental behaviors can have co-benefits such as improving health. Essentially, consciously focusing on a non-environmental goal (with environmental co-benefits) may lead to between-domain spillover effects in pursuing that goal.

The other example of between-domain spillover bore a similarity to the previous example in that the manifest process governing the spillover effect was attributed to a non-environmental goal; having a simpler and less expensive lifestyle:

The environmentally friendly behaviors that formed the focus of the spillover relationship (an energy-efficient home and an electric vehicle) remain undefined in terms of their causal direction (i.e., which behavior was the catalyst, and which behavior was catalyzed), though the speaker acknowledges the difficulty in recollecting a clear example in line with the expressed difficulty in recalling spillover more generally.

Another variant of behavioral spillover, termed contextual (Nilsson et al., 2017), or situational spillover in the gray literature (Austin et al., 2011), was reported in all three countries, albeit rarely. We found limited evidence for two kinds of contextual spillover in the interviews (where a behavior is performed by an individual in one context and then another, and where a behavior is transfered between different individuals across contexts). The few examples of contextual spillover that came up in the interviews were reported almost exclusively by more environmentally engaged participants. Two types of context came up in these accounts. One involved the transfer of behavior between work and home. Here a Danish participant explains how working in the environmental transportation sector had influenced more sustainable travel decisions outside of work:

The speaker describes how working on projects to reduce carbon emissions from transportation at work, had crossed a focal boundary between work and private life, leading to them questioning their private-sphere travel-mode choices and being more aware of the merits of using more “intelligent” travel modes such as public transport, car-pooling schemes, as well as not owning a car. Central to the account is the idea of consistency in behavior between one context and another.

Another type of contextual spillover involved exposure to wider cultural contexts beyond the workplace where pro-environmental behaviors were more socially normative than at home. With reference to contextual spillover effects from exposure to other cultures with contrasting pro-environmental behavioral norms, participants who had traveled, studied or worked overseas in countries with higher standards of environmentally responsible behavior reported a need to act consistently after returning home:

Perhaps unsurprisingly, examples of this kind of contextual spillover were only found in Brazil and China, where infrastructure conducive to facilitating behaviors such as recycling was less widespread than in countries such as Denmark. This kind of example suggests that exposure to supportive pro-environmental norms and infrastructure for engagement can, at least in some cases, be internalized in ways that predispose an individual to perform that behavior in other cultural contexts, including those contexts where engagement is markedly more difficult. Processes related to behavioral consistency are central to the contextual spillover effects described in the second extract. The speaker explains how reverting to a system where waste was not recycled sparked a visceral sensation of cognitive dissonance that underpinned the spillover effect. Therefore, if behavior is internalized then it may persist in contexts where it is neither the norm, nor easy to do.

There was also very limited evidence for the second type of contextual spillover involving the transfer of behavior between different individuals across contexts. This type of spillover was reported exclusively by participants in the more environmentally engaged group in Brazil. Such accounts constructed the spillover of behaviors through social diffusion. For example, participants discussed how making changes to their homes to make them more energy-efficient had served as an exemplar for friends and neighbors, who borrowed ideas for making changes to their own homes. In addition, participants who worked in the environmental sector also spoke of how their work influenced people outside of work to become more pro-environmental as a result. In the following extract the speaker illustrates the latter kind by discussing the way in which their work potentially caused their partner to make substantial lifestyle changes without being directly influenced:

While the partner’s motivation to change their lifestyle is not unequivocally attributed to the speaker’s influence, an interest in the identity and role of the speaker as a WWF employee constitute the catalyst rather than behavior. The idea that the effect was not catalyzed in other ways (for example by the partner observing the speaker) is questioned in the account where the speaker suggests that it is “only” because of the speaker’s role and that their behavior was more sustainable than their own.

There was some evidence that narrow pro-environmental behavioral repertoires may be another reason for limited spillover effects, as a scarcity of potential catalyzing actions reduces the chance of one behavior leading to another. In the following extract with a less engaged participant in Brazil, the speaker attributes their inability to recollect behavioral spillover to a lack of experience of performing pro-environmental behaviors and a lack of intrinsic motivation:

In addition to having a very narrow range of simple behaviors that, nonetheless confer a positive sense of wellbeing, the kinds of behaviors performed do not lead to others because they lack the necessary “stimulation” or “reward.” This suggests a lack of intrinsic motivation, which precludes the possibility of adopting more committed actions.

When asked about whether they could recall any personal experience of spillover, participants also spoke about how they never consciously reflected on their behaviors, nor discussed them with others. Instead pro-environmental behaviors were constructed as having a routine, habitual character:

Whereas accounts of behavioral spillover tended to highlight the salience of conscious awareness of behavior (including environmental impacts, alignment with broader goals and consistency with other behaviors), accounts such as the above that attempt to account for a lack of recollection of spillover provide a counterpoint. In contrast, they describe how spillover may have been impeded by a lack of conscious reflection on the perfunctory action being performed, particularly in terms of that action’s relationship to other behaviors. This is also suggested in terms of the character of the behavior itself, in which pro-environmental actions are “just things that I do” as opposed to practices with the intention of reducing one’s environmental impact.

The relative frequency of within-domain spillover supports previous work proposing that behavioral spillover is likelier when behaviors are similar (Thøgersen, 2004), or share the same routines or resources (Littleford et al., 2014; Margetts and Kashima, 2017). Within-domain spillovers may also require less effort. This parallels other research measuring a gradual expansion of organic food purchasing using supermarket loyalty card and scanner data (as opposed to less robust self-report measures) (Juhl et al., 2017).

While there was some commonality of behavioral clusters leading to reported spillover effects, there was little clarity as to which specific behaviors catalyzed others. It appears unlikely that specific behaviors function as entry points to adopting other actions. There was also little evidence that easier behaviors lead to more committed ones. While unsupported by our analysis, this may be due to a lack of self-efficacy. Increased self-efficacy has been demonstrated not only as a motivator of environmentally responsible action, but as a mediator of further engagement in wider behaviors (Lauren et al., 2018) and warrants further study. There was also some evidence that engaging in one behavior catalyzed wider interpersonal engagement. This might be more effective in generating wider culture change than focusing on spillovers involving the adoption of individual behaviors. This also parallels other work in which it is argued that engagement in green behavior catalyzing pro-environmental policy support has greater potential impact than conventional spillovers between behaviors (Thøgersen and Noblet, 2012).

Behavioral interventions potentially risk marginal returns if behavioral repertoires are limited to “simple and painless” actions (Thøgersen and Crompton, 2009). It is also evident from everyday life that if we engage in one environmentally responsible action then this does not guarantee that we will then engage in other behaviors, akin to ascending a “virtuous escalator” (Thøgersen and Crompton, 2009). We found very little evidence across cultures where a behavior from one cluster catalyzed another behavior from a different cluster. If spillover is to fulfill its potential in generating wider lifestyle change, interventions must find ways to transcend these boundaries and catalyze the voluntary adoption of wider, more committed practices beyond existing behavioral repertoires.

From our isolated examples of between-domain spillover, an initial step could lie in highlighting the co-benefits of pro-environmental engagement (such as promoting health or voluntary simplicity). This is not to say that environmental justifications for engagement are less important, as without some degree of intrinsic pro-environmental motivation, spillover may be undermined if a perceived benefit or incentive disappears (Evans et al., 2013). Nonetheless, some individuals will value the environment more than others and so strengthening pro-environmental salience in decision-making across the board is likely to be extremely difficult. Research has shown that certain types of co-benefits (for example, the creation of more benevolent and caring communities) can motivate sustainable behavior change for those who are environmentally committed to varying degrees (Bain et al., 2016). This could create the initial momentum for change. Further to the above, catalyzing wider interpersonal engagement might also be an effective way of generating wider culture change.

We also found evidence for contextual spillover effects. Previous studies have also documented the transfer of behavior between different contexts including work and home (Lee et al., 1995; Tudor et al., 2007; Andersson et al., 2012). This opens the possibility that promoting pro-environmental practices at work could be spread to other life spheres. However, as the examples from the interviews came from participants who worked in the environmental sector, it is possible that pre-existing values could have facilitated consistency (Thøgersen, 2012). Other work has found contextual spillover mediated via identification with the pro-environmental ethos or values within non-environmental organizations (Rashid and Mohammad, 2011; Loverock et al., 2015). Workplace coercion might also lead to behavioral transfer from the workplace to the home, which could influence less environmentally engaged employees. Andersson et al. (2012) report increases in home waste separation practices following the introduction of an environmental management system at work.

Interpersonal spillover effects were also reported that operated along processes of social diffusion (McKenzie-Mohr and Schultz, 2014). Taken together, the evidence suggests that if behavior can be transferred between contexts then it might also then be spread via social diffusion to multiple people within the household under the right conditions. There is also the possibility of a reversal of direction from home to work, though differences in roles, levels of responsibility and control in the workplace might constrain the degree to which household practices could transfer to the workplace (Maki et al., 2016).

Following the lead of CBSM, rather than attempting to identify and promote the adoption of what are judged to be the most potent behavioral catalysts, it may be more productive to tailor interventions based on the receptiveness of different audiences. It may be that in some situations different kinds of spillover pathways will be open or closed. A better understanding of the ways in which different types of spillover operate would be a suitable target for CBSM interventions. In particular, CBSM strategies could utilize community connections and block leaders to create small-scale cultural shifts that can grow and spread through society (McKenzie-Mohr et al., 2011). Small-scale community approaches might also be more successful in reaching those who feel that they lack the capacity to engage in more committed pro-environmental actions, as indicated in the interviews. Community initiatives that foster supportive environments in which more sustainable behaviors can develop, may also be more impactful than individual private-sphere initiatives that ignore the relevance of the social context.