Pro-Environmental and Pro-Social Engagement in Sustainable Consumption: Exploratory Study

: Sustainable consumption, provision of a clean and healthy environment, as well as improve-ments to the quality of life of current and future generations, are all integral parts of the sustainable development strategy, which is understood as a compromise between the environmental, economic and social objectives of society. The pro-environmental and pro-social consumer engagement in sustainable consumption may lead to behavioral change, thus contributing to the resolution of current global challenges. Although recently the pro-environmental and pro-social engagement concept has received considerable attention, there is still no consensus on what determines it. Moreover, the recent research is limited to identifying individual factors of this phenomenon. Therefore, the purpose of this study is to explore the factors that determine pro-environmental and pro-social consumer engagement in sustainable consumption. The authors employed a qualitative method approach, conducting semi-structured interviews with consumers engaged in sustainable consumption in Lithuania. The research results reveal that these consumers were affected by cognitive, attitudinal and psychosocial factors. In terms of external factors, consumers named contextual factors for sustainable consumption, social norms and the promotion of sustainable consumption. Research results also show an additional internal factor of perceived responsibility, which means perceived duty as an individual to do good for society and the environment.


Introduction
Sustainable consumption is a practical process that involves the economy, society, and environment in reaching for sustainable development goals [1][2][3][4]. Geiger et al. [5] define sustainable consumption as a behavior associated with long-term understanding of the consequences of individual consumption. Sustainable consumption is associated with changes in consumer behavior [6], i.e., purchasing exclusive (organic, green or fair trade) products or reducing consumption [7,8]. Nonetheless, each time a consumer desires to give preference to a sustainable way of life, they find themselves in a complex decision-making process [9]. It is therefore highly important to identify the factors that could drive consumers towards sustainable consumption. Following Kaiser and Byrka [10] and Kadic-Maglajlic et al. [11], two types of engagement in sustainable consumption can be distinguished: pro-environmental and pro-social engagement. Empirical evidence supports such a classification. Engagement in sustainable consumption is expressed through participation in related events and support thereto, communication and engagement with other members of society, and a conscious focus on environmental and social issues as the key driver of behavioral change [11]. Banytė et al. [12] claim that both aspects of engagement leading to sustainable development should be analyzed in order to develop a holistic understanding of engagement as a phenomenon. In their study, Vivek et al. [13] demonstrate that consumers who care about environmental and social issues and their possible solutions are engaged in sustainable consumption to a greater degree, and this aspect of engagement could be defined as pro-environmental and pro-social engagement. Such engagement has a stronger effect than pro-environmental or pro-social behavior, as it connects consumer communities who share conscious attention to environmental and social issues [11]. To demonstrate the links between pro-environmental and pro-social engagement in sustainable consumption, several researchers [11,14,15] have conducted studies among the consumer group of young adults. Such studies were prompted by the need to analyze the behavior of the younger generation. Nonetheless, there are very few representative studies revealing the behavior of different age groups. The influence of culture on pro-environmental engagement has been studied by Milfont [16]; however, the study does not cover pro-social engagement. Researchers Loy and Reese [17] take a broader approach towards the analysis of the influence of global identity on the individual's pro-environmental and pro-social engagement. Griskevicius et al. [18] demonstrate that pro-social engagement and sacrifice for the common good encourage consumer willingness for sustainable consumption. However, though substantial research has been conducted concerning pro-environmental and pro-social consumer engagement in sustainable consumption, research on the factors determining such engagement has been sparse. An analysis of research studies that identify the determining factors of pro-environmental and pro-social engagement in sustainable consumption suggests that researchers predominantly analyze individual factors, rarely attributing them to categories of internal or external factors. For example, according to the findings of Schmitt et al. [19], the more satisfied the consumer is with life, the more inclined they are to engage in sustainable consumption. Meanwhile, a study by Milfont and Sibley [20] exploring personality traits that influence pro-environmental engagement shows that amiable, selfless and responsible individuals are more inclined to engage in sustainable consumption. The influence of personal and group values on pro-environmental engagement has also been studied by Bombiak [21], Maziriri et al. [22], and Bouman, Steg and Zawadzki [23]. Gagné [24] demonstrates that group values and norms can promote pro-social engagement. According to Johnston and Krettenauer [25], consumer self-esteem and self-identity contribute to pro-social engagement in sustainable consumption. Conversely, a study by Ali et al. [26] suggests that collectivist trends can have a greater impact, and consumers prioritizing common welfare issues over personal welfare are more inclined towards sustainable consumption. Collective wellbeing-oriented individuals prioritize group goals over personal ones, and are more inclined to collaborate and engage in sustainable consumption, such as waste sorting. Janmaimool and Denpaiboon [27], Goldman et al. [28] and Wang, Wang, Li and Yang [29] have analyzed the groups of factors determining pro-environmental engagement in sustainable consumption. Kadic-Maglajlic et al. [11] provides substantiation for the influence of consumer's self-identity and values on pro-environmental and pro-social engagement in sustainable consumption. Nonetheless, the above listed studies are confined to the analysis of only a few determinants of pro-environmental and pro-social engagement in sustainable consumption, or rest on a fragmented analysis focused on a single pro-environmental or pro-social engagement aspect. Thus, the present study addresses this research gap by exploring the factors that determine pro-environmental and pro-social consumer engagement in sustainable consumption. To reach this aim, a comprehensive literature review is provided in the article and presents the research background in the area concerned. A qualitative research method was applied to gain a deeper insight into the phenomenon. It involved semi-structured interviews with consumers engaged in sustainable consumption in Lithuania. The findings, main conclusions and limitations of the study are presented below.

Pro-Environmental and Pro-Social Engagement
Consumers are increasingly concerned about environmental, social and economic issues, and are willing to act on these concerns. According to the findings by Milfont and Schultz [30], consumers not only take interest in these issues, but become personally involved, and aspire to contribute to the implementation of the respective solutions. Crane [31] supports this view, and emphasizes that consumers who turn their attention to ethical and environmental issues demonstrate their concern by adapting their consumption habits. Pro-environmental and pro-social consumer engagement starts with changes to personal behavior that are expressed through consumption. This substantiates own participation (e.g., in events related to pro-environmental and pro-social issues); the creation of social connections (by interacting and engaging others), and the conscious focusing of attention (interest in pro-environmental and pro-social issues) [11]. According to Bowden [32], Jaakkola and Alexander [33] and Brodie et al. [34], consumer engagement is construed as a psychological state expressed through the consumer's interactive experience with an object. This psychological state defines the dimensional character of this concept and its dependence on the engagement object and context. This may include not only the consumer's actions in relation to the purchase of goods [35], but also the consumer's influence on other consumers [36].
A literature review shows that various authors have conceptualized consumer engagement as a single unitary construct [33,35,37] as well as a multi-dimensional phenomenon that includes cognitive, emotional, behavioral [32,34] and social aspects [38,39]. According to Kuvykaitė and Tarutė [40], the cognitive dimension is the state of consumer cognition that manifests itself through the focus on and interest in a certain object (company, brand, virtual social network, brand community), while the emotional dimension includes the inner pleasure caused by the engagement object, enthusiasm, inspiration, and sense of pride. The behavior dimension includes participation, vigor, and activation [41]. Vivek et al. [13] describe the dimensions of engagement as conscious attention, enthusiastic participation, and social connection. Jaakkola and Alexander [33] and Brodie et al. [34] define the pro-social engagement as a psychological state that reveals a willingness to act for the benefit of society. This engagement is linked to the willingness to support, comfort, share, and collaborate, and brings greater benefit to others than to oneself [42]. De Groot and Steg [43] support this by claiming that pro-social engagement promotes consumers' needs to explore issues related to society, such as fair trade and labor rights, charity or social conditions.
In view of the above definition of engagement [33,34], pro-environmental engagement could also be referred to as the consumer's psychological state that expresses the willingness to act for the benefit of environmental protection. Pro-environmental engagement may reveal itself in a private domain (as precepts and desires associated with the purchase and use of sustainable products, choice of mobility or energy consumption habits) and a public domain (willingness to support policy aimed at improvement of the environmental condition [44]). According to De Groot and Steg [43], pro-environmental engagement may also be construed as a case of pro-social engagement, as the engaged consumers do not gain individual benefit for themselves, with the greatest efforts being directed towards other people's benefit. Consumer engagement is considered to be one of the priorities in marketing research [45]. Such research analyzes various engagement objects, engagement antecedents and consequences, etc. There also are attempts to investigate measures and methods which could help motivate consumers to engage. According to Pronello and Gaborieau [46], all consumers are different, and understanding the factors behind their intentions is highly important. Based on Kollmuss and Agyeman [47], the factors influencing pro-environmental and pro-social engagement are further grouped into external and internal factors.

Internal Antecedents of Pro-Environmental and Pro-Social Engagement
Researchers employ various theories and models to define consumers' sustainable behavior [28]. Nonetheless, Kollmuss and Agyeman [47] have suggested that, due to its complexity, the question of what forms environmentally friendly behavior is impossible to visualize using a single system or framework, as it might be too complicated or lose its applicability or meaning. There are, however, certain common points shared by different models. Kollmuss and Agyeman [47] identify the following internal factors determining consumer pro-environmental engagement: motivation, environmental knowledge, understanding, values, attitude, emotions, control, responsibility, and priorities. A study by Wang, Wang, Li and Yang [29] demonstrates that pro-environmental self-identity and pro-environmental commitment influenced by altruism and the sense of guilt are the factors that most contribute to pro-environmental engagement. According to the study by Janmaimool and Denpaiboon [27], the internal factors could be grouped into three categories: cognitive, attitudinal, and psychosocial (see Table 1).
Cognitive factors. Cognitive factors are associated with the consumers' level of consciousness, knowledge, beliefs, thoughts, and environmental awareness [48]. These cognitive processes include thinking, knowledge, memory, judgement, and problem solving. Responsibility felt by the consumers for the global condition and the need to change this condition are other highly important factors [49]. According to researchers [50][51][52][53][54], having gained respective environmental knowledge, consumers often become more aware and more motivated to consume sustainably. Environmental knowledge determines how consumers perceive the environmental consequences of their consumption choices [55]. On the other hand, according to Kullmuss and Agyeman [47], it is very important to differentiate between environmental knowledge about facts and knowledge about actions. Knowledge about facts relates to information about issues, and their causes and effects, while knowledge about actions relates to actions that should be taken for sustainable consumption. According to Tanner and Kast [56], knowledge about actions has a greater effect on sustainable consumption. Scientific background analysis [14,27,[57][58][59] enables the identification of environmental knowledge as the factor that contributes to pro-environmental and pro-social engagement.
Self-efficacy is construed as a person's individual ability to make judgements about a prospective situation and, having mobilized the motivation, to correct the behavior enabling them to deal with the challenges. In other words, it is the consumer's belief that their personal contribution may help solve global issues [60]. Lauren et al. [61], Janmaimool and Denpaiboon [27], and Jugert et al. [62] agree that self-efficacy promotes pro-environmental and pro-social engagement in sustainable consumption, which is characterized by such sustainable consumption behavior as waste sorting [63], lower energy consumption [64] or the use of reusable shopping bags [65].
Pro-environmental self-identity demonstrates what the consumer thinks about themselves in terms of being an environment-friendly person [66]. The consumer who identifies oneself as a person who engages in sustainable behavior would be more inclined to engage in sustainable consumption. Such a consumer tends to sort waste more often [67,68], use sustainable transport [66], prioritize organic products [69], and engage in pro-environmental action [67]. According to researchers [11,29,67,[70][71][72], pro-environmental self-identity positively influences consumer pro-environmental and pro-social engagement in sustainable consumption.
Pro-environmental commitment is another important factor that determines proenvironmental and pro-social engagement in sustainable consumption. Committed consumers make an effort to engage in sustainable behavior [70], even if this requires sacrifice [71], for example, paying a higher price for organic food [72]. Pro-environmental commitment determines greater motivation [73] and the desire to correct one's own behavior for the sake of the preservation of the environment [70]. Studies confirm [29,71,74,75] that pro-environmental commitment is positively related to pro-environmental and prosocial consumer engagement in sustainable consumption.
Attitudinal factors. These factors are associated with the attitude towards and care about the environment. Researchers analyzing this group of factors [27,76] have identified four key factors that determine pro-environmental and pro-social engagement in sustainable consumption: values, personal norms, environmental attitude, and place attachment. Consumers who are characterized by environmental values are more inclined to engage in sustainable consumption and not only intend to, but also do consume in a more sustainable way [43]. According to Schwartz [77], two groups of values must be mentioned in an analysis thereof. The self-transcendence group includes consumers who have strong inner motivation, are helpful, responsible, honest, friendly, open, and advocate social justice. Meanwhile, consumers who possess values that are based on self-enhancement care about other members of society and allocate relatively less time to personal needs [78]. Several investigations [11,35,76,79,80] have confirmed that a stronger manifestation of these values relates to pro-environmental and pro-social engagement and more sustainable consumption.
Authors also identify personal norms as an internal factor influencing pro-environmental and pro-social engagement. These norms are defined as an individual's perception of the appropriate behavior in a respective situation [81]. According to Stern [43] and Onel [82], personal norms are one of the key factors determining pro-environmental engagement. By following personal norms, the consumer becomes morally committed to behave in a certain environment-friendly way. This may, in turn, help develop the desire to engage in sustainable consumption [82]. Doran and Larsen [83], Hidaya and Agustin [84] and Bouman and Steg [79] support the links between personal norms and pro-environmental and pro-social engagement in sustainable consumption.
Environmental attitude is defined as a favorable or unfavorable judgement and reaction to objects, people and situations [85]. Positive environmental attitude can be associated with greater engagement in sustainable consumption [86]. According to the value-beliefnorm (VBN) theory [43], environmental attitude is one of the key drivers of sustainable consumption. On the other hand, although environmental attitude determines greater engagement, a gap between environmental attitude and actual sustainable consumption behavior is often observed [87]. According to researchers [10,27,47,80,86], pro-environmental self-identity positively influences consumer pro-environmental and pro-social engagement in sustainable consumption.
Researchers [88,89] also reveal a positive relation between place attachment and pro-environmental engagement in sustainable consumption. Place attachment could be associated with positive emotions [89,90]. Such consumers seek to preserve the place they live in, as they are emotionally connected to it. Research studies by Song and Soopramanien [74], Fang et al. [86], and Janmaimool and Denpaiboon [27] provide substantiation for the links between place attachment and pro-environmental and pro-social engagement in sustainable consumption.
Psychosocial factors. Research studies [91,92] have demonstrated that optimistic consumers are capable of solving problems, while less optimistic consumers are inclined to avoid or ignore them [93]. According to Schmitt et al. [19], consumers experience greater subjective good when they behave according to how they understand their worth in the eyes of others (e.g., volunteer, donate to charity, or engage in other acts of goodness). Research studies by Weber [94] and Schmitt et al. [19] reveal that consumers who are optimistic and satisfied with their lives are more engaged in sustainable consumption. Binder and Blankenberg [95] and Schmitt et al. [19] have determined that pro-environmental and pro-social engagement is associated with one's satisfaction with life. The link between these factors could be construed as a mutual cause-and-effect relationship: if the consumer feels happy, vitally important and satisfied, they tend to become more engaged in sustainable consumption. By engaging in sustainable consumption, they, in turn, feel more satisfied with their life [96]. Table 1. Internal factors determining pro-environmental and pro-social engagement in sustainable consumption.

Factor Groups Factors Authors
Cognitive factors

External Factors of Pro-Environmental and Pro-Social Engagement
Consumer pro-environmental and pro-social engagement in sustainable consumption is influenced not only by internal, but also external factors. Identification and exploration of the latter could help change consumer behavior towards greater sustainability (see Table 2). Kollmuss and Agyeman [47] identify the following external factors: institutional [98,99], economic, and social and cultural factors. Meanwhile, in their research study, Piligrimienė et al. [100] identify such external factors as conditions, social environment, and promotion.
Based on the analysis of academics [101,102], the contextual factors that include specific conditions and opportunities are among the external factors that influence proenvironmental and pro-social consumer engagement in sustainable consumption. External conditions range from various phases of sustainable consumption of products or services (acquisition, usage, and disposal) [5], to public transport and wastewater infrastructure, recycling, etc. [103]. Inadequate conditions may interfere with consumer engagement in sustainable consumption irrespective of their attitude to environmental issues [29]. According to Maki et al. [104], who analyzed energy conservation behavior, it could be claimed that the price of certain objects or services stands as an external condition which has a positive or negative effect on the engagement in sustainable consumption.
Promotion is another external factor that influences pro-environmental and pro-social consumer engagement in sustainable consumption. According to Thøgersen [105], creation of favorable external drivers may function as effective promotion for the consumers to consume in a more sustainable way. Political interventions should be directed towards consumer promotion, empowerment, engagement, and setting an example [106] or giving a nudge [107] to promote and cultivate sustainable consumption. Product safety surveillance and labeling performed by the state authorities are among the external promotion actions helping the consumer track and consume in a more sustainable way [56]. According to researchers [108], behavioral changes could be promoted by local authorities increasing public awareness in the area of sustainable food consumption. Such contribution could come in the form of activities related to promotion of organic food (including TV advertisements, information leaflets, regional symposiums, seminars, etc.). Piligrimienė et al. [100] have found that promotion has a positive effect on consumer engagement in sustainable consumption. Social norms Abusafieh and Razem [109]; Huber et al. [110]; Lubell et al. [111]; Fritsche et al. [112]; Janmaimool and Denpaiboon [27]; Ojala [14] Social factors are among the key factors of sustainable consumption [109]. Consumers are often influenced by other peoples' presence, behavior and expectations, which manifest themselves through social norms. Social norms cover informal general rules, expectations or beliefs of people's social groups related to the behavior that would be expected of an individual or a community member [81]. Social norms are a strong force influencing individual behavior in relation to certain actions [113]. Huber et al. [110] note that social norms are in fact one of the determining factors that have considerable influence on proenvironmental and pro-social engagement, and the more consumers become engaged, the more the individual would observe the informal rules of the group behavior culture and become engaged in sustainable consumption. Scientific literature analysis suggests that there is a positive relation between norms and pro-environmental [112,114] and prosocial consumer engagement [111]. If there is a community norm related to environmental protection and social norms, the norm is recognized by the community members, and they are expected to engage in sustainable consumption [27], in particular when the norm is demonstrated to children by their parents [14].
Recent research suggests that pro-environmental and pro-social engagement could be driven by various internal and external factors, which have been analyzed separately. Nevertheless, the pro-environmental and pro-social engagement, as well as factors that determine this phenomenon, is relatively new in consumer behavior research and needs to be further investigated. In addition, the already existing literature provides a foundation on which we based our empirical study.

Materials and Methods
This study aims to uncover the factors that determine pro-environmental and prosocial consumer engagement in sustainable consumption. In its design, the research study is dedicated to exploring a new phenomenon by identifying new factors, or factors which have been conceptually proven in scientific literature to determine such engagement. For this purpose, an individual semi-structured interview method was employed. We built our interview guide based on prior findings on factors of pro-environmental and pro-social engagement in sustainable consumption. Thereby, semi-structured interviews enabled additional questions, so that additional factors could be found and constantly used in consumer behavior studies [115].
In order to explore the research subject more comprehensively, the interviewees were sampled according to them possessing traits relevant to the research context. The interviewees were selected on the basis of the following criteria: (1) the respondent is active and engaged in environmental and social activity; (2) the activity is associated with sustainable consumption, (3) active engagement in the activity has lasted for no less than five years. The sample size was 9 interviewees. We followed the approach that sample size in qualitative content analysis research should focus on uncovering phenomena in context and situation [116]. Researchers indicate [117,118] that for the research where the aim is to understand and confirm commonalities in within a fairly homogenous sample like ours (i.e., consumers highly engaged in sustainable consumption), 4-12 is likely to be sufficient. In summary, this was dictated by the research aim to collect data within the defined research limits and, upon reaching the moment where no new data were obtained, to reasonably conclude that the mentioned attributes existed, and complete the research at that point.
The research used a mixed sample based on purposive sampling and snowball sampling methods. The first interviewee was selected based on the above three criteria. Contact details for other respondents were received at the end of the every interview under the snowball sampling principle. The snowball technique is commonly used when it is difficult to identify members of the desired population, i.e., zero waste consumers.
The individual semi-structured interview was based on a pre-established plan (Appendix A) that provided the interview topics and guidelines. It was subject to certain changes and corrections, but the general interview structure was maintained. Prior to each interview, the respondents were informed that the purpose of the research was to gain an understanding about their experiences relating to their engagement in sustainable consumption. The researcher encouraged the participants to describe actual experiences. All interviews began with a general question running along the lines of, "Could you begin by telling me about some of the things that you are doing in order to live more sustainably?" and "Why is it important for you?" This opening question began the dialogue in an open-ended manner and the participants were encouraged to describe actual experiences related to their general perceptions. The interview outline covered several key topics: (1) understanding of sustainable consumption; (2) forms of consumer engagement; (3) identification of the internal and external factors determining pro-environmental and pro-social engagement in sustainable consumption. At the end of the interview, the respondents were asked closed-ended questions, to determine the social-demographic characteristics (gender, age, highest level of education achieved, income level and how long participant has been actively engaged in environmental and social activity associated with sustainable consumption). In line with Jaakkola and Alexander, and Brodie et al. [33,34], to be actively engaged in environmental and social activity associated with sustainable consumption means the consumer's psychological state expresses the willingness to act for the benefit of environmental and social protection. This may include not only the consumer's actions in relation to the purchase of goods [35], but also the consumer's influence on other consumers [36]. That means how long the respondents have been trying to live more sustainably and trying to influence other consumers through different activities. Each individual interview was recorded by the researcher using voice recording applications or devices in order to provide reliable research findings. The length of the interviews ranged from 50 min to 70 min and each interview was audiotaped. The interview texts were then transcribed and put into a computer file. The interviewees' details were coded for confidentiality purposes. In the present research, the data were analyzed using the qualitative content analysis method. According to Elo and Kyngäs [119], qualitative content analysis may be defined as empirical, methodological text analysis within the framework of the texts, based on the methodologically reasonable steps of analysis. In our study we used directed content analysis [119] as the existing theory on factors of pro-environmental and pro-social engagement in sustainable consumption has been used. The content of the transcribed interview text was subject to consistent analysis and divided into analytical units. The categories and subcategories were then formulated in order to interpret and answer research questions. This study aims to provide substantiation for analytical generalization. Theoretical concepts serve as templates that can then be compared to empirical results.

Results
All nine research participants satisfied the personality trait criteria set in the process of criterion selection and could therefore provide the information needed. We conducted interviews until we reached theoretical saturation-that is, the last few interviews did not provide new insights-making the sample size appropriate for this study.
The research findings are presented as follows: first, consumers' general understanding of engagement in sustainable consumption; second, main forms of consumer engagement; finally, internal and external factors determining greater pro-environmental and pro-social engagement in sustainable consumption. At the beginning of the interview, the interviewees were asked about their actions and experiences, gradually moving to questions regarding their opinions and feelings. Thereby, speaking about their experiences, the respondent would find it easier to present the relevant context and explore the topic in depth, which facilitates the understanding of their own feelings and expression of opinion [120]. The participants' age ranged from 25 to 45 years. Three males and six females participated in the study. Five interviewees were actively engaged in environmental and social activity associated with sustainable consumption for more than 5 years, three interviewees, for more than 10 years, and one respondent, for more than 15 years. The social-demographic characteristics of the sample are summarized in Table 3. Actively engaged in environmental and social activity associated with sustainable consumption more than 5 years 5 more than 10 years 3 more than 15 years 1

Income level
Significantly worse than most Lithuanian people 0 Worse than most Lithuanian people 0 Like most Lithuanian people 7 Slightly better than most Lithuanian people 2 Significantly better than most Lithuanian people 0 The first objective of the qualitative research was to reveal the participants' understanding of sustainable consumption. During the interviews, the interviewees were consequently asked what they thought about its relation to their lives. All the interviewees stated that it was an important part of their lives, and that they would contemplate about it at work, home, and during their leisure time. However, when asked to describe and name it, the interviewees emphasized different aspects of sustainable consumption. Four of the nine representatives associated sustainable consumption with conscious choice, critical thinking, and environmental buying behavior. In their description of sustainable consumption, certain interviewees noted that it was strongly related to the reconsideration of their own needs, limitation of buying and sparing behavior, i.e., actions that involve daily minimized consumption choices. Interviews revealed respondents' strong connection with nature, and concern about its preservation and environmental aspects, which could be associated with consumer behavior related to the preservation of their social and physical environment (see Table 4). The conducted study demonstrated what forms of engagement (see Table 5) were expressed in the interviewees' daily activities. The majority of the interviewees thought that the main way to engage consumers in environmental activities would be through their own engagement to the degree that would enable the person to coach others. According to the interviewees' opinions, it is important to share their acquired knowledge in an attempt to find an individual path and approach to another person, as for some people it is the information that encourages them to take action, while for others it is the sanctioning of some action. The interviews also clearly showed that setting a personal example and consuming sustainably in daily life are viewed as having the most powerful impact in encouraging other consumers to change their behavior. When asked how knowledge could be shared or examples set to the people around them, the majority of the interviewees claimed that social networks and blogs were a great tool to achieve that goal. A few interviewees insisted that it is not only very important to spread the message on social networks and other media, but focus strongly on the educational system in order to start educating the younger generation as early as possible as well. It should be emphasized that when speaking of their personal experience of active engagement, such as participation in various communities and processes related to sustainable consumption, the majority of interviewees did not think of this as exceptional behavior. The majority claimed that this should be a norm of behavior for all consumers and could be associated with different aspects of consumer engagement, including not only actions, but also participants' behavior, psychological state, mood, and strong moral principles and values.

Media/radio
And this engagement is everywhere, and the radio show is engaging, because when I talk about the best practices how people can build businesses based on this, this should inspire young people to try it out, and that also works.
Educational system < . . . > the emphasis in the educational system should be mostly placed on teaching children to live, to put the knowledge to practice < . . . > how to save energy resources, water, electricity, and so on. < . . . > ecology became an important part of my life when I was at school, when I started to think for myself in my senior year. < . . . > but my dream is environmental education in general terms.
The study also identified the factors determining pro-environmental and pro-social engagement in sustainable consumption. The internal factors identified through the scientific literature analysis (environmental knowledge, self-efficacy, pro-environmental self-identity, environmental values, environmental attitude, personal norms, place attachment, and satisfaction with life) were also recognized during the interviews (see Table 6).
It should be noted that all the participants demonstrated a high level of self-efficacy, having no doubt that their actions could contribute to solving global issues. They clearly realized their connection to nature and felt a responsibility to take care of it. The majority of the participants revealed a strong attachment to their residential location. Meanwhile, satisfaction with life manifested itself as a bi-directional factor. Nevertheless, it is difficult to clearly state whether satisfaction with life determines engagement in sustainable consumption, or whether engagement in sustainable consumption determines satisfaction with life. Table 6. Internal factors of pro-environmental and pro-social engagement in sustainable consumption.

Category Quotes
Environmental knowledge < . . . > the knowledge, the work, getting the information < . . . >. < . . . > The consumers of the new generation are very well educated in this respect, they act very responsibly when choosing brands, as they wish to know the brand, its essence, the narrative of the objects they use, and they find this important. < . . . > I highly encouraged them to sort certain plastics as we work only with certain kinds of it, and they know a lot now < . . . > < . . . > then you try to surprise them with the facts saying that only this small percentage of plastic is recycled, so that the person would think about the alternatives, about how they could avoid the resulting plastic.
Self-efficacy < . . . > to empower yourself primarily to make change, to believe that I can embrace change and make use of my own abilities, say, communication, socialization abilities and engage people < . . . >. < . . . > Sometimes I like to send a letter to someone, to a company, saying: "Hey, it would be cool if you could change something at your company. < . . . > Motivation also comes from knowing that if I'm not going to do something, then probably others won't do it too, nothing will happen then, it's just this inner desire to seek change and contribute to it.
Pro-environmental self-identity < . . . > I associate nature with our survival as a species, the survival of those closest to me and my own survival < . . . >. < . . . > we live on this planet, not somewhere else, but here, and we walk on it. And if we don't take care of it, it means we don't take care of ourselves, it's as simple as that < . . . > < . . . > it's strange and illogical to not pay attention to what's going on in nature, and how we treat it, because this actually means we don't pay attention to ourselves, we are doing something bad to ourselves.
Pro-environmental commitment < . . . > the sense of duty that I live on this planet and I depend on the environment < . . . >. I probably feel responsible for this and even guilty, if I do not encourage others. < . . . > we cannot continue living like this, this is unsustainable, we have to feel a responsibility < . . . >. Air quality, water quality are the things we need to care about, and I am encouraged by this. < . . . > here, look at the beauty that we live in, but we find a candy wrap in this beauty, and it doesn't fit, but then think about how we could work together to make sure this doesn't happen < . . . >. < . . . > I think this is related to mutual relationships and our relationship with nature, the way we treat each other is the way we treat nature, and we find inspiration in nature and, having taken the inspiration, we share it among ourselves and become better to each other.
Personal norms < . . . > you have to not lose yourself, follow the path, and not really mind what is done out of fear, out of fear to change probably, well, just to not take the negative emotions and rules too seriously, and to listen to what the person inside of you is telling you. < . . . > this is quite a big part of my life, this is how I make a difference then. < . . . > my moral values are telling me that we have to respect the environment. < . . . > This came to me naturally, it is now in my blood, this is normal, but when it is destroyed, the man goes against nature and his own natural existence.

Place attachment
It is important for me to do this in Lithuania, because I was born here, I grew up here, this is my land, and it probably is important to do this here < . . . >. < . . . > I like it very much, and I find this meaningful to identify the territory of your actions, and the fact that this is in Lithuania makes it an additional benefit, aspect. The conducted research demonstrated that the external factors (see Table 7), which were also mentioned during the interviews, were not motivating enough to engage interviewees in sustainable consumption. The interviewees claimed that the contextual factors, lack of accessibility, or economic factors neither stopped nor encouraged them to engage in sustainable consumption. The majority of the interviewees claimed that they would always find ways to consume in a sustainable manner, irrespective of the contextual factors. The factor of promotion raised a lot of doubts. The scientific literature analysis predicted that promotion would function as an important factor. Nonetheless, the question received diverging opinions, and a few interviewees expressed the lack of existence of this factor to be able to make appropriate judgements in relation to it: < . . . > this requires political leadership, certain discounts, and promotions for people to do this. Finally, in reports, speeches, which I lack the most, some official position < . . . > Table 7. External factors of pro-environmental and pro-social engagement in sustainable consumption.

Category Quotes
Conditions < . . . > it is quite difficult to find food without packaging or organic food in other towns. < . . . .> we go to the farmers' market, and we are quite successful in finding food without package, this makes us happy, but you need time; you need to find time, your spots, get to know them, visit them, because they are not as popular or very convenient to reach < . . . >. < . . . > does it really require money, isn't there any other way, could it be possible to just go to your friend and ask them to sew you a piece of clothing in exchange for something else < . . . > < . . . > but an ordinary person cannot afford organic products. People often don't think that the simple seasonal potato, Lithuanian-grown carrot is more organic than the carrot imported from Spain, carrying the organic labeling, and brought from far away < . . . >.
Promotion < . . . > I think that the large businesses and policy makers have the power and can form society, being at this level, they can launch a product line, they can shape people's mindsets < . . . >. < . . . > promotion to sort waste brings us to the point where you see that 70% is plastic. Then you start seeing and thinking that you probably shouldn't buy these amounts of food in packaging. < . . . > because we have already solved the container deposit < . . . > but there was considerable economic pressure to do so, not consciousness for sure.
Social norms < . . . > people started showing support to me, and the support helped me develop the whole project. < . . . > I have found people who want to join, and when we met, we united and enhanced the desire, so this is the success of development of the project. < . . . > being with the people who share your ideas < . . . > it is a great pleasure to socialize with people who have the same level of passion, then you become charged with their energy, and can start turning the wheel even stronger. < . . . > one of the key drivers is the sense of making a difference in the community, and I also enjoy the connection with people when we are doing something together, when we are not apart by ourselves, but together. Unity is what motivates.
It was noticed during the study that the more the respondent was engaged, the less they were subject to emerging disturbances: < . . . > I addressed the Ministry of Environment having just started the activity, I wrote them a letter asking about any existing programs, explained my idea. The response I received could actually make a person not want to do anything. < . . . > all the changes regarding non-labeling of certain types of plastic, non-labeling of the packages have disappointed me, this is a step back < . . . > It is actually a bit sad, but encourages you to not give up < . . . >.
The conducted research has suggested social norms as the strongest prevailing external factor that encourages pro-environmental and pro-social engagement in sustainable consumption. Support from the participants' environment (community), following unwritten rules, and meeting expectations were important factors for all the research participants.
During the interviews, an additional internal factor was identified. It could potentially determine pro-environmental and pro-social consumer engagement in sustainable behavior (see Table 8). Perceived responsibility is the factor which, in case of its growth, encourages consumers to engage in altruistic behavior without sparing their own efforts. Consumers' perceived responsibility may determine respective consumption choices and sustainable consumption actions [121]. Eight out of the nine research participants claimed that they have started their activity having perceived their own responsibility not only for the present moment, but also for the quality of life of the future generations. Table 8. Interviewees' internal factor of pro-environmental and pro-social engagement in sustainable consumption.

Category Quotes
Perceived responsibility < . . . > we must start doing it now, there's no other way, we must talk a lot < . . . > convey this to our children and bring them up this way.
There's this sense of duty, the sense that we are leaving something for the future generations, and this is something that we have been given to preserve.
I probably feel responsible for this and even guilty, if I do not encourage others.
< . . . > we cannot continue living like this, this is unsustainable, we have to feel the responsibility < . . . > for others. < . . . > because we are using our finite resources without thinking about the future, about how our children will live, and how our grandchildren will live < . . . >. < . . . > well, I've asked myself whether there's something I can do personally for my children to grow up in a cleaner, more beautiful environment. < . . . > speaking globally, what would be left after me for the future generation, but the fact is that you always think about your own children, and you want to make a difference for your own children < . . . >.
Research shows that sustainable consumption is understood as the control of one's own desires and goals, or the correction of the desires and goals in view of the changing conditions. Environmental values and morals comprise a strong foundation. The critical thinking that emerges in the decision-making process leads to a conscious choice, which is strongly associated with the aspects of reconsideration of one's own needs, limitation of buying, and sparing behavior. The goal behind sustainable consumption could be associated with environmental goals and concern about nature.
The aspect of engagement as a psychological state was indicated by the respondents' expressed desire to share pro-environmental knowledge and set an example of sustainable consumption, thereby encouraging other consumers to follow suit. The main engagement tools utilized by Lithuanian consumers are social networks, websites, and other media, as well as communication within various communities, in particular focusing on the educational system and the younger generation.
Internal factors (environmental knowledge, self-efficacy, pro-environmental selfidentity, pro-environmental commitment, environmental values, environmental attitude, personal norms, place attachment, and satisfaction with life) influencing the pro-environmental and pro-social engagement were expressed more strongly than the external factors, but the latter also influenced engagement in sustainable consumption. On the other hand, the interviewees were particularly engaged in this activity, and it cannot be definitely claimed that majority of the Lithuanians would do the same, or that they would not find such external factors as contextual factors, promotions and social norms important.
During the research, the interviewees were also found to consider the feeling of being responsible, and the perception thereof, as important. The perceived responsibility means recognition of the consequences of one's own actions without blaming others, but by assuming one's own liability. The importance of this factor is substantiated by the data analysis results of the qualitative research. Nonetheless, the degree of influence of all the factors revealed could be substantiated only by conducting quantitative research.

Discussion
This paper explores pro-environmental and pro-social engagement in sustainable consumption. It contributes to the literature by revealing the reasons, forms and factors behind it. Previous research on pro-environmental and pro-social engagement has been sparse, namely regarding factors that drive this kind of engagement. The research participants' experience and formed attitude towards sustainable consumption demonstrates their understanding of sustainable consumption and the forms thereof used by them. The study also identifies the internal and external factors that determine pro-environmental and pro-social engagement in sustainable consumption. This is the first study in which all factors of pro-environmental and pro-social engagement in sustainable consumption have been investigated.
The research results reveal that, for the majority of participants, sustainable consumption does not equal subjecting oneself and one's own desires to limitations. On the contrary, the participants demonstrating sparing behavior consider this to be more a result of a conscious choice rather than self-limitation. These results are in line with previous studies [122] which have revealed frugality to be a fundamental behavioral attribute of sustainable consumption, signaling a reduced level of consumption. This study also reveals key forms used to demonstrate engagement in sustainable consumption. These are primarily virtual tools that can serve as sources of information, can be shared, and provide the possibility for connection. Social networks and virtual communities are particularly relevant. Previous research also reveals the role of virtual communities and social media in the context of engagement in sustainable consumption [123].
Further, as expected, it has been found [58,59,61,70,71,75,80] that the internal factors (environmental knowledge, self-efficacy, pro-environmental self-identity, pro-environmental commitment, environmental values, environmental attitude, personal norms, place attachment, and satisfaction with life) determining their engagement in sustainable consumption, are important. This is in line with the research by Kadic-Maglajlic et al. [11], Janmaimool and Denpaiboon [27], Wang, Wang, Li and Yang [29] and Piligrimienė et al. [100]. In addition, this study identifies new factors, such as perceived responsibility, the effect of which on sustainable consumption has been revealed by Luchs et al. [121]. Nonetheless, this factor has not been analyzed as a factor determining pro-environmental and pro-social engagement.

Conclusions and Further Directions
Active zero waste and other community members who participated in the study claimed that such factors as promotion, social norms or conditions are not very important. The influence of internal factors is essential in the formation of sustainable consumption, and they are easier to control or manipulate in order to achieve behavioral changes [100]. Nevertheless, the results of this study may be inexact as the participants sampled for the study were truly motivated people, capable of controlling their behavior and signaling environmental values. Their inner state and resolution could be considered solid to the degree that the external factors have a weaker effect on them. Meanwhile, people who are less motivated may be more subject to the influence of external factors.
The conclusions of this study cannot be regarded as representing the opinion and attitude of all consumers in the country, in particular given that the interviews intended to explore the phenomenon were conducted with the participants who were truly engaged in pro-environmental and pro-social behavior, and demonstrated the actions of sustainable consumption. The empirical study confirmed the existence of the proposed factors. Nonetheless, from a methodological perspective, the character of qualitative research requires further verification of pro-environmental and pro-social consumer engagement in sustainable consumption in order to reveal its influence on sustainable consumption behavior. Further research could involve the analysis of the magnitude of the effect of each individual factor or groups of factors (internal or external) on pro-environmental and pro-social engagement in sustainable consumption. Developing the descriptive or causal research design based on findings of the current research will provide valuable data related with the investigated phenomena.
Researchers encountered the challenge of finding male participants when searching for the interviewees and performing the analysis of persons engaged in pro-environmental or pro-social behavior. It would therefore be reasonable to conduct a factor analysis for pro-environmental and pro-social engagement in sustainable consumption in terms of different genders. Having analyzed pro-environmental engagement, Ojala [14] also determined different a frequency of engagement by gender. It should also be noted that the results of the present study are geographically limited to reflect the specific situation in Lithuania only. Similar studies could be conducted in other countries as well, taking into consideration economic and cultural differences. However, regardless of these limitations, the present research is believed to provide a deeper understanding of pro-environmental and pro-social consumer engagement in sustainable consumption.  Are you a member of any environmental organization? If so, how are you actively involved in this organization (s)?
Can you tell me about your motives to consume sustainably? What is your emotional state when you engage in such activities? Can you describe it. Tell us, how do you encourage others to be more sustainable?
Identification of the pro-environmental and pro-social engagement in sustainable consumption (internal factors) Why is it important for you to protect the environment? Can you tell me more? What do you think are the causes of environmental/social problems? Does concern for the environment/community affect your buying and consumption habits? How? When you think about all the pro-environmental behaviors that you do/did, do you see them as similar or different? Comment.
Identification of the pro-environmental and pro-social engagement in sustainable consumption (external factors) Are your neighbors and friends trying to act responsibly and ecologically? How do they do that? What challenges do you face in consuming organic, sustainable products? Do you think people in our country understand environmental problems properly? What initiatives would increase their engagement in sustainable consumption? What do you think about Lithuanian government's environmental policy?

Social-demographic characteristics
The respondents were asked closed-ended questions (gender, age, highest level of education achieved, income level and how long participant are actively engaged in environmental and social activity associated with sustainable consumption).