The ‘Concept-As-a-Tool’ Strategy for Familiarizing Young Children with the Idea of Sustainability

Abstract

This paper concerns a three-cycle design research that explores the feasibility of designing a learning environment that could support preschoolers to (a) build basic ecological knowledge and (b) develop familiarity with the concept of sustainability and other socio-environmental concepts that might contribute to their socio-environmental awareness. We focus on the third research cycle, emphasizing the implementation of the learning environment and the resulting ‘design theory’ for combining biology and sustainability education at young ages. Grounded in constructivism, our design utilizes approaches like ‘problem-posing,’ ‘possible futures,’ and ‘problem seekers–problem solvers–action takers’ as design principles. Qualitative and quantitative analysis of the pre-/post-interviews with the 30 participating preschoolers indicated improvements in their ecological understanding as well as in their familiarity with sustainability-related concepts. Moreover, the iterative design process led to the articulation of the ‘Concept-As-a-Tool’ (CAT) strategy, a design theory that conceptualizes sustainability as a decision-making tool connecting ecological knowledge and socio-environmental action-oriented thinking in early childhood education. The findings provide initial support for this design theory within the context of the present study.

1. Introduction

1.1. Rationale of the Study

During their journey on Earth, humans have influenced the ecosystems maintained on it in various ways. Climate change, resource depletion, and the ongoing extinction of species are just a few examples of the impact of human activity on the environment (Caniglia et al., 2021; Lam et al., 2020). Human health and survival, which are inextricably linked to the overall well-being of ecosystems, are increasingly endangered by modern lifestyles (Debrah et al., 2021; J. Elliott, 2012; Griggs et al., 2013; Robert et al., 2005; Saviano et al., 2017). Thus, the shift in modern societies towards sustainable development is not a choice but an absolute necessity (Fien & Tilbury, 2002; Salvia et al., 2019; Spiteri, 2018).

Considering this, it seems imperative to consistently provide children with educational experiences that will familiarize them with urgent socio-environmental issues and facilitate them in developing the solid socio-environmental awareness they need to be able to act in favor of the environment and other people’s well-being (Ardoin & Bowers, 2020; J. Davis & Elliott, 2023; David, 2007; J. Davis, 2009; Iliopoulou, 2016; Mackey, 2012; Pramling Samuelsson & Kaga, 2008). Early childhood constitutes a critical period for shaping knowledge- and value-based attitudes toward the environment and society that may facilitate the development of lifelong, responsible behaviors (Collado et al., 2020; Huggins & Evans, 2018; Iskos & Karakosta, 2015). In other words, it appears that now more than ever, the so-called education for sustainability (EfS) should be an educational priority and begin as early as preschool for the welfare of everyone (S. Elliott et al., 2020; Ferguson et al., 2021; Kahriman-Ozturk et al., 2012; Pramling Samuelsson, 2011; Pramling Samuelsson & Kaga, 2008; Somerville & Williams, 2015; Spiteri, 2018; Zguir et al., 2021).

However, this is not always the case. The educational agenda of Greece, for instance, has lagged behind in systematically embedding EfS in early childhood, although the country is facing serious environmental challenges like waste management inefficiencies, pollution, unsustainable urban expansion, or fires (Sakellariou & Banou, 2022). While curriculum reforms have begun to include sustainability elements in early childhood education (Institute of Educational Policy, 2022), they mostly target later school levels (Petkou et al., 2025). Studies have shown that Greek preschool teachers may lack conceptual clarity regarding the multiple dimensions of sustainability (economic, social, environmental), as well as the necessary pedagogical tools to integrate EfS meaningfully into their daily school practice (Maidou et al., 2019; Gavrilas et al., 2024).

Incorporating EfS in preschools, both in Greece and worldwide, would be easier to achieve if a rich body of research comprehensively explored the most appropriate ways to treat preschoolers as future citizens in the service of the environment and society. The literature, however, reveals a research gap. Although empirical early childhood education for sustainability (ECEfS) studies have increased during the last decade, much of the literature continues to emphasize the rationale for integrating sustainability in early childhood education or developing theoretical models, rather than rigorously evaluating actual classroom outcomes (Ärlemalm-Hagsér, 2013; Cutter-Mackenzie & Edwards, 2013; J. M. Davis, 2022; Duhn, 2012; S. Elliott & Davis, 2018; Engdahl & Furu, 2022; Hedefalk et al., 2015; Reid & Scott, 2006; Smidt, 2018; Spiteri, 2018). Existing empirical studies have mainly focused on children’s environmental attitudes, experiences in nature, sustainability-related behaviors, or the implementation of specific sustainability themes and activities (Biber et al., 2023; Kos et al., 2016; Li et al., 2024; Otto & Pensini, 2017; Vodopivec & Šindic, 2025). Comparatively less attention has been given to the iterative design and evaluation of learning environments that systematically combine ecological knowledge, socio-environmental concepts, and sustainability-oriented reasoning within a coherent instructional framework. The present study addresses this gap by drawing on both ECEfS and biology didactics literature to develop and iteratively refine a learning environment aimed at simultaneously supporting ecological understanding and emerging socio-environmental reasoning in young children.

1.2. Theoretical Background

1.2.1. Theoretical Suggestions

The ECEfS literature offers several theoretical suggestions that are worth testing. One of the most interesting is to create learning environments in which young children could experience the roles of ‘problem seekers’, ‘problem solvers’ and ‘action takers’ (Ärlemalm-Hagsér, 2013; Collado et al., 2020; J. Davis, 2009; J. Davis & Elliott, 2023; Caniglia et al., 2021); i.e., learning environments in which they would have the opportunity to (a) develop familiarity with socio-environmental problems that may mean something to them, their families or the place they live, (b) look for possible solutions to these problems, and finally (c) plan the implementation of them or even try to implement such solutions.

Another interesting suggestion is the ‘possible futures’ approach (Campbell & Speldewinde, 2022; Engdahl & Furu, 2022; Hicks & Holden, 2007; Zguir et al., 2021). The idea is to help young children understand the ‘present–future’ relationship and their own role in it. More specifically, it is suggested that children should be given the opportunity to (a) examine how their present actions may affect the future of the environment and humanity, (b) decide if they like the future they are heading for, and, in cases where they do not like it, (c) examine how they should change their current actions in order to create a more desirable future instead (Hicks & Holden, 2007).

Both the ‘problem seekers–problem solvers–action takers’ approach, and the ‘possible futures’ approach require the active participation of children while they are in the process of learning (Ardoin & Bowers, 2020; Somerville & Williams, 2015). Children are placed at the center of the solution. Instead of becoming passive receivers of information, they take an active role that allows them to explore, wonder, be in a process of forming responsible attitudes, and discuss actions for a better future for themselves, their fellow humans, and the environment. It is clear that both of these approaches are in harmony with the theoretical framework of constructivism (Bächtold, 2013; Fosnot, 2013, Tobin, 2012). According to this, when children encounter something new, they try to understand it by using ideas they have already built in previous experiences. These pre-existing or initial ideas can be modified as children themselves actively attempt to explain the new experiences while using them individually or within peer groups (Driver et al., 1994).

Children’s active participation in the learning process is also encouraged in the context of the ‘problem-posing’ approach (Ferguson et al., 2021; Klaassen, 1995). The suggestion is that children should be constantly aware of what they are doing, what they will do next, and why they are doing it or will do it. This is attempted by posing worth-exploring questions to serve as the so-called ‘global’ or ‘local’ motives for the children (Lijnse & Klaassen, 2004). More specifically, each learning environment session designed according to the ‘problem-posing’ approach should be guided by a ‘central question’ that serves as the children’s ‘local’ motive, i.e., as their motive throughout the specific session. This central question is posed at the beginning and answered at the end of the session, whereas its answer is directly connected to the next session’s central question. The answers to all the sessions’ central questions contribute to answering the overall question of the learning environment, which serves as the children’s ‘global’ motive, i.e., as their general motive throughout the whole learning environment. Such organization of the learning environment gives children a sense of purpose and possibly helps them to maintain their interest as they move from session to session.

All the above may serve as design principles for creating learning environments to support young children in starting to develop the socio-environmental awareness they will need as modern adults. On the other hand, drawing on biology didactics, one can spot concepts that are essential for children’s introductory understanding of ecosystems. Preschool children appear able to cope with basic ecological concepts, such as habitat, organisms’ interdependence within food chains, human interventions in ecosystems, or waste management combined with recycling and decomposition (Debrah et al., 2021; Ergazaki & Andriotou, 2010; Korfiatis & Tunnicliffe, 2012; Shutaleva et al., 2020). The concept of decomposition may be more demanding at such a young age but still manageable (Dimitriou & Christidou, 2007; Ergazaki et al., 2009). Such concepts may also fit in a context that aims to highlight the interconnectedness of nature, humans, and economy for preschoolers (Ergazaki & Andriotou, 2010; Palmer et al., 1996) and facilitate the development of children’s socio-environmental awareness.

The latter requires an essential understanding of critical socio-environmental ideas such as, for instance, the ‘present–future’, ‘local–global’, or ‘individual–collective’ relationships that are integral to the idea of ‘sustainability’ but likely appear highly demanding in early childhood. However, even concepts (either scientific or socio-environmental) that seem complex at first sight may be didactically transformed to acquire meaning for children of a certain age and thus be meaningfully explored by them (Lam et al., 2020; Ravanis, 2010; Wooltorton et al., 2020; Zidny et al., 2020). The notions of ‘didactic transposition’ (Chevallard, 1985) and ‘educational reconstruction’ (Duit et al., 2012; Kattmann et al., 1996) underline the need and potential for such an adaptation.

Taken together, these perspectives constitute the theoretical foundation of the present study. Constructivism provides the overarching learning framework, emphasizing children’s construction of meaning through their active engagement with target ideas. Within this framework, the ‘problem-posing’, ‘possible futures’, and ‘problem seekers–problem solvers–action takers’ approaches offer complementary pedagogical principles for engaging young children with socio-environmental issues, future consequences, and opportunities for action. Biology didactics contributes the ecological concepts that form the scientific content of the learning environment, while the notions of didactic transposition and educational reconstruction guide their adaptation to preschool children’s profile.

1.2.2. Objectives and Research Questions

Considering all these, we decided to explore whether it is feasible to design a learning environment that could support preschoolers in enhancing their conceptual understanding of nature along with their socio-environmental awareness, as well as to articulate a design theory that could guide the design of learning environments with similar objectives (Hedefalk et al., 2015). More specifically, we performed a three-cycle design research study aiming to design a learning environment that could support preschoolers in (a) building basic ecological knowledge and (b) familiarizing themselves with the idea of ‘sustainability’ and other socio-environmental ideas critical to their socio-environmental awareness. This paper is concerned not just with the implementation of the designed learning environment but also with the design’s theoretical output; in other words, with the ‘design theory’ or ‘domain-specific didactical structure’ (Boersma & Waarlo, 2009) that could emerge from our design with the potential to further inform early teaching and learning that engages with the idea of sustainability. So, the research questions (RQs) we address are the following:

• Which design theory could emerge from the design of a learning environment that aims to promote the idea of sustainability in early childhood education?
• To what extent do children’s learning outcomes provide support for the proposed design theory?

2. Materials and Methods

The study we report here is a study of design research (McKenney & Reeves, 2018), which includes an exploratory phase and a phase of three research cycles (RC) with three case studies. In the exploratory phase, we first defined the learning objectives (LOs) and design principles (Section 2.1). The latter are the principles that would guide the design of our learning environment in line with our learning objectives (LOs) and theoretical framework. Then, we designed the first version of our learning environment (LE1), which aimed at supporting preschool children in (a) constructing basic ecological knowledge and (b) strengthening their socio-environmental awareness. LE1 had a ‘decomposition/recycling part’ which we tested in the RC1 case study, and we used the findings for redesigning an elaborated, new version of the learning environment (LE2). This had two parts: the ‘forest part’, which was tested in a case study of the 2nd research cycle (Kasimati & Ergazaki, 2020), and the ‘decomposition/recycling part’, which was tested in another one (Kasimati & Ergazaki, 2019). The findings of these case studies were used for redesigning a further elaborated, new, third version of the learning environment (LE3), which included one more part with some first explorations of the target socio-environmental ideas (‘intro part’) and had the idea of sustainability underlying all its parts. LE3 was tested within the 3rd research cycle, which concerns us here with extra emphasis on its theoretical output. A case study design was considered appropriate, as the primary aim of each research cycle was to obtain an in-depth understanding of how the learning environment functioned in practice and to further refine and articulate the emerging design theory, as well as to avoid establishing causal relationships.

The participants of all three research cycles (NRC1 = 20, NRC2 = 15, NRC3 = 30) were pupils of a public kindergarten, situated in a semi-urban area of Patras with medium/high socio-economic status. The participants of the 3rd research cycle that concerns us here (N = 30, 16 girls/14 boys, age 4.5–5.5) were selected through convenience sampling, as access to the kindergarten was facilitated by the classroom teacher’s willingness to support the implementation of the study. Participation was voluntary, and informed consent was obtained from all participants’ parents/guardians prior to data collection. The study was approved by the Ethics Committee of the Department of Educational Sciences and Early Childhood Education, University of Patras, Greece (Protocol No. 1, 19 December 2017). The study ensured participants’ anonymity and confidentiality. All data were anonymized and securely stored, and no identifying information is included in the present study.

Moreover, children had the opportunity to meet the interviewer/first author before the beginning of the study, become acquainted with them, and give their own assent to participate. According to their teacher, children were quite familiar with educational interactions, and they had not been engaged in formal activities about our target ideas up to that point. For the implementation of LE3, children were divided into six groups of five. Each group (a) included members of mixed age and mixed level and (b) separately took part in fifteen 20–30 min sessions, led by the first author across an eight-week period.

2.1. Shaping a Design Theory

In the exploratory phase, in order to design LE1, we set a series of learning objectives concerning ecological and socio-environmental ideas (e.g., ‘decomposition’ and ‘present–future’). We also came up with four ‘design principles’ based on the theoretical suggestions of the ECEfS literature (Hedefalk et al., 2015; Somerville & Williams, 2015; J. Davis & Elliott, 2023; S. Elliott et al., 2020). The learning objectives (LOs) and design principles were further developed, and some new ones were also added as we moved on from RC1 to RC2 and then from RC2 to RC3. The successive research cycles contributed not only to the refinement of the learning environment but also to the gradual development of the emerging design theory. Findings from RC1 indicated that preschool children were able to engage with ecological concepts related to decomposition, recycling, and waste management, but experienced difficulties with future-oriented reasoning and with broader socio-environmental dimensions. Consequently, LE2 was expanded to include additional socio-environmental concepts and activities explicitly addressing issues such as human–nature relationships, equality, local–global interconnections, and individual and collective action. Findings from RC2 showed that children were able to engage with most of these concepts, although concepts such as local–global interdependence and individual–collective action remained challenging. These findings, together with evidence of children’s ability to reason about socio-environmental issues, informed the design of LE3, in which sustainability was introduced more explicitly as a decision-making tool. The progressive refinement of the learning environment across the three research cycles ultimately contributed to the articulation of the ‘Concept-As-a-Tool’ (CAT) strategy.

For example, the LOs of LE1 were focused mainly on decomposition and recycling, whereas the LOs of the final version of our learning environment (LE3) included LOs concerning (a) ecological ideas, like ‘habitat’ ‘forest impact on abiotic environment and human life’ (in short, ‘forest value’), ‘food chain’ and ‘decomposition’, and (b) socio-environmental ideas, like ‘present–future’, ‘local–global’, ‘individual–collective’, ‘human–nature equality’, ‘human–human equality’, ‘recycling process’, ‘everyday practices for the environment and fellow humans’ (i.e., consuming responsibly, donating things to fellow humans that we do not need but might be useful to them, avoiding products in small packages, recycling, and protecting forests), and ‘sustainability’. For a more detailed overview of the learning objectives, see Appendix A.

Similarly, the design principles guiding the design of the first two versions of our learning environment (LE1, LE2) were the following:

• Design principle 1: The learning environment should encourage children to detect environmental problems, allow them to look for possible solutions and plan actions to implement these solutions, in the context of exploring possible scenarios for the future. The 1st design principle concerns the overall structure of LE3, and it is connected to all its LOs.
• Design principle 2: The learning environment should include a broad question to guide it as a whole (‘overall question’), as well as a series of partial questions, each addressed in a specific session and having an answer that can lead to the next one (‘central questions’). The 2nd design principle concerns the overall structure of LE3 and is connected to all its LOs.
• Design principle 3: The learning environment should include activities that support the active participation of the children (“hands on/minds on” activities) according to the principles of constructivism. The 3rd design principle is connected to LO8 of ‘LE3-forest’, as well as to LO2-4 and LO6 of ‘LE3-decompsition/recycling’.
• Design principle 4: The learning environment should apply the notion of ‘didactic transposition’ for the concepts it introduces. The 4th design principle concerns the overall structure of LE3, and it is connected to all its LOs.
  After the implementation of LE2, a new fifth ‘design principle’ concerning the concept of sustainability was added for the design of LE3, which is outlined as follows:
• Design principle 5: The learning environment should facilitate children to approach the concept of sustainability as a decision-making tool. More specifically, the learning environment should support children to become familiar with the idea of taking into account all three dimensions (environment, society, economy) when investigating problems of environmental/socio-economic interest in scenarios adapted to their abilities. The 5th design principle relates to (a) LO10 of ‘LE3-forest’, (b) LO9 of ‘LE3-decomposition/recycling’, and (c) LO6 of ‘LE3-intro’. Moreover, it should be noted that integrating this new principle into our design was crucial for the articulation of our design theory, as explained later in the paper.

So, the design of the final version of the learning environment (LE3) was guided by the ‘problem posing approach’ proposed by Klaassen (1995). According to this, for children to acquire and maintain awareness and interest in what they are engaged with, the learning environment should be organized with questions that could serve as motives, both ‘locally’ and ‘globally’; in other words, as motives for the partial sessions and for the learning environment as a whole (Fien & Tilbury, 2002; Taimur & Sattar, 2020; Salvia et al., 2019). Our overall question was about how one should think when trying to address a socio-environmental problem: should they consider (a) just the present or the present and the future at the same time, (b) just the environment, or the environment and people (economy, society, health) at the same time, and (c) themselves as an active part of the problems’ solution?

As a consequence, our design also drew on the ‘possible future approach’ proposed by Hicks and Holden (2007) and the ‘problem seekers, problem solvers, and action takers approach’ proposed by S. Elliott and Davis (2009), both presented in the Introduction. All three approaches are consistent with the broad theoretical framework of constructivism (Ardoin & Bowers, 2020; Fosnot, 2013; Somerville & Williams, 2015) and allowed us to provide the children with the opportunity to actively explore and use simplified, didactically transformed versions of our target concepts and to be introduced to the concept of ‘sustainability’ in a way that takes into account their very young age.

The design of LE3 was therefore informed by a synthesis of constructivist notions, the ‘problem-posing’ approach, the ‘possible futures’ approach, and the ‘problem seekers–problem solvers–action takers’ approach. These perspectives provided the theoretical foundation for designing learning experiences that engage young children with ecological knowledge, socio-environmental problems, future consequences, and opportunities for exploring possible actions.

This synthesis also informed the development of the design theory presented later in the paper. More specifically, sustainability was conceptualized as a decision-making tool through which children could evaluate socio-environmental problems, consider alternative courses of action, and reflect on their consequences for both humans and the environment, while building and implementing ecological knowledge. Thus, the resulting design theory, the Concept-As-a-Tool (CAT) strategy, builds on existing ECEfS approaches while extending them through the explicit use of sustainability as the organizing concept connecting ecological knowledge, socio-environmental reasoning, and action-oriented decision-making in early childhood education. This represents the main theoretical contribution of the present study.

2.2. Exploring the Utility of the Design Theory: RC3/LE3

To explore the utility of our design theory, we will draw on the third research cycle (RC3) and the findings of its case study surrounding the learning outcomes of the final version of our learning environment (LE3). So, the following sub-sections outline the approach we used in this mixed-model case study and detail the processes of data collection and data analysis.

2.2.1. Overview of the Learning Environment-3

The third version of our learning environment (LE3) consists of three parts: the ‘introductory part’ with seven activities, the ‘forest part’ with eight, and the ‘decomposition/recycling part’ with seven. Each part was implemented in five sessions. Each session lasted 35–40 min and was driven by a ‘central question’, the answer to which was linked to the ‘central question’ of the next session. In sum, there were a total of 22 activities implemented in 15 sessions, which were carried out with one group of five children each.

In the ‘introductory part’, we initiated the exploration of socio-environmental concepts to foster children’s deeper understanding. Unlike the other parts, this one featured standalone activities without a larger context. Each session began with a stimulus (e.g., clock, book, globe) leading to a discussion on the target socio-environmental idea. Children were encouraged to share thoughts and guided by scaffolding questions to reach conclusions. For instance, ‘sustainability’ was discussed through guided dialogues, including two decision-making scenarios: ‘ecotourism in a poor African village’ and ‘a new factory near a poor city’. These scenarios required considering environmental, human, and economic factors equally, promoting conflict resolution and thus practicing sustainability in decision-making. In the second scenario, children explored ways to open the factory while avoiding/minimizing negative impacts on the environment and humans, maximizing benefits for the economy and people.

The ‘forest part’ and ‘decomposition–recycling part’ were integrated into two scenarios: (a) the ‘forest’ scenario (modified version of Hadzigeorgiou et al. (2011)), where a city faced unemployment and decided to cut a forest for jobs, and (b) the ‘decomposition/recycling’ scenario, where waste management costs led to landfill use over recycling. Both scenarios prioritized short-term economic gains, neglecting long-term environmental and health risks.

Children explored an undesirable ‘possible future’ linked to these unsustainable choices, developed knowledge-based explanations, and planned present actions to avoid it. Activities included interactive storytelling, guided dialogue, brainstorming, empirical testing/observation, grouping, interactive puppet shows, and role-playing. These age-appropriate activities aimed to foster active participation and enhance understanding of target concepts. For a detailed overview of teaching–learning activities, see Appendix B.

2.2.2. The Data Collection

The data for the evaluation of the learning environment were collected through individual pre/post interviews conducted in a quiet area of the children’s school. The interviews were semi-structured. While all children were asked the same core questions according to the interview protocols, the interviewer also used non-leading follow-up questions when needed to clarify responses and encourage children to elaborate on their reasoning, in line with qualitative interviewing practices in early childhood research.

We used two different interview protocols, one concerning the ‘forest part’ of the learning environment and another concerning the ‘decomposition/recycling part’. We started the pre-interviews with the ‘forest’ protocol (duration: 15–25 min) and continued with the ‘decomposition/recycling’ protocol (duration: 15–25 min). Right after, we implemented the ‘introductory part’ and the ‘forest part’ for each of the six groups of five children separately. One week later, we conducted post-interviews with the ‘forest protocol’. The next step was to implement the ‘decomposition/recycling part’ the same way as before. One week later, we conducted post-interviews with the ‘decomposition/recycling’ protocol (duration: 15–25 min).

The sequence of implementation reflected the intended progression of concepts within LE3. Children first participated in the introductory and forest parts, which introduced core socio-environmental concepts, before engaging with the decomposition/recycling part where these concepts, including sustainability, were revisited and applied in a different context. Regarding data collection, all pre-interviews were conducted prior to the implementation of LE3, while post-interviews were conducted one week after the completion of the corresponding intervention sessions.

The ‘forest’ interview protocol consisted of ten open-ended questions that aimed to explore children’s understanding of ‘habitat’, ‘forest value’ (i.e., impact on abiotic environment and human life), the ‘food chain’, the ‘present–future’ relationship, the ‘local–global’ relationship, ‘equality’, the ‘individual–collective’ relationship, and ‘forest protection’. The questions were integrated into a scenario similar to that of the ‘forest part’: an overpopulated city has a housing problem and cuts down its forest to create space for building. Similarly, the ‘decomposition/recycling’ interview protocol consisted of 11 open-ended questions that aimed to explore the children’s understanding of ‘decomposition’, ‘waste management’, ‘recycling’, ‘sustainability’, and the children’s intentions to act for the environment and for their fellow humans through realistic action scenarios on waste management and on everyday consumption habits and solidarity practices. In both cases, we also used cards with images that could help the children understand the questions more easily.

Focusing on ‘sustainability’, we used a ‘decision-making scenario’ about creating an entertainment park in a forest with rare biodiversity near a poor city. In a city council meeting, some supported the park idea for potential benefits like jobs, tourism, and prosperity, while others opposed it due to concerns about disturbing wildlife, pollution, and health risks. For detailed interview protocols, see Appendix C.

2.2.3. The Data Analysis

The pre-/post-interviews were audio-recorded, transcribed verbatim, and analyzed using qualitative content analysis. The qualitative data analysis software NVivo 2 (QSR International, Melbourne, Australia) was used to support the organization, coding, and retrieval of the data. The children’s responses were coded as (a) ‘naïve’, when wrong or stating ignorance (‘don’t know’), (b) ‘transitional’, when correct but incomplete, and finally (c) ‘informed’, when correct and complete at the same time. For instance, in case of the sustainability question, the children’s responses were coded as (a) ‘naïve’, when they did not consider the pros and cons for the environment, people, and economy in order to make a decision, (b) ‘transitional’, when they did consider all these facets at the same time, but they were not able to make a decision, and (c) ‘informed’, when they did consider all the facets at the same time, and they were able to make a decision by reconciling conflicts of interests. The coding process was conducted collaboratively by the two authors. Coding decisions were discussed throughout the analysis process and jointly agreed upon, resulting in a shared coding framework and interpretation of the data. As coding was undertaken collaboratively rather than independently, estimating an inter-rater reliability coefficient was not applicable. For a more detailed overview of coding and examples of the children’s pre/post responses in their words, see Appendix D.

Then, the frequency of occurrence of the three categories for each question was calculated. In order to conduct a quantitative analysis, numerical values were assigned to each response category (‘naïve’ = 1, ‘transitional’ = 2, ‘informed’ = 3). These categories were conceptualized as representing progressively higher levels of understanding, ranging from misunderstanding or no understanding (‘naïve’) to partial understanding (‘transitional’), and finally to more complete and integrated understanding (‘informed’). The numerical values assigned to the categories were used to reflect this ordinal progression rather than to imply equal intervals between categories. Therefore, the categories were treated as ordered (ordinal) levels of understanding for the purposes of quantitative analysis. Since the resulting data were ordinal in nature, non-parametric statistical procedures were considered more appropriate than parametric alternatives. Thus, pre/post-test differences for each question and in total were examined using the Wilcoxon signed-rank test. For the quantitative analysis, the null hypothesis assumed no statistically significant difference between the children’s pre- and post-interview scores, whereas the alternative hypothesis assumed a statistically significant difference between them. These hypotheses were examined using the Wilcoxon signed-rank test.

3. Results

3.1. Results for RQ1

The Design Theory

Taking into account the features of the designed learning environment (learning objectives, content, design principles), we developed a ‘design theory’, which might be used in similar cases of combining biological education and socio-environmental awareness in early childhood education. Certainly, the content of such learning environments is directly linked with the learning objectives and can vary quite a bit, but it should always take into account the children’s young age. This was the main criterion for all the ‘design principles’ that guided our design (the ‘possible futures approach’, the ‘problem seekers, problem solvers, and action takers approaches’, and the ‘problem-solving approach’) and shaped its theoretical output.

As mentioned before, the ‘design theory’ that emerged from our research (Figure 1) can be called the ‘Concept-As-a-Tool’ strategy (in short, the CAT strategy) because it introduces the concept of sustainability as a decision-making tool.

Such an introduction requires creating (a) one or more decision-making ‘frameworks’ and (b) a series of successive ‘stages’ for evaluating the decision, revising the decision, and planning personal actions. The stages (i) are interconnected with each other, (ii) require a shift in focus from the present to the future and back to the present, and (iii) require an active role from children. In more detail:

• Framework(s): A socio-environmental problem (or more) within the understanding potential of young children, and an unsustainable decision made for the solution can provide the necessary framework(s). The problem needs to be understood as such by the children themselves.
• Evaluation stage/shift to the future: The unsustainable decision enters an evaluation process which is based on projecting its consequences into the future. Children detect the future consequences for both humans and the environment, allowing the concept of sustainability to emerge as a tool. In addition, future consequences raise ‘how’ or ‘why’ questions for children, thus providing opportunities to build new ecological knowledge.
• Revision stage/return to the present: The ecological knowledge built in the previous stage is used now, as children explore other solutions or corrective actions, returning to the present.
• Stage of focus on individual contribution: The solutions or corrective actions resulting from the previous stage are further explored here, with the aim of highlighting specific ways in which children can make a personal contribution, the value of this contribution and the power it gives them.

Each ‘stage’ includes age-appropriate hands-on and minds-on activities that require the children’s active participation. The activities are organized into sessions, each guided by a local question that has to do with the session’s target concepts. The answer to the local question of a session is connected to the local question of the next one. The global/overall question that should guide the whole design of a sustainability-introducing learning environment, according to the ‘CAT strategy’, is the following: how should one think when addressing a socio-environmental problem? Should they consider (a) the present and the future at the same time, (b) the environment and people (economy, society, health) at the same time, or (c) themselves as action takers for the problem’s solution or not?

The ‘CAT strategy’ appeared to provide a useful framework within the context of its articulation. More specifically, as shown in the next sub-section, the ‘CAT strategy’-based LE3 that was tested in the RC3 case study supported students in familiarizing themselves with the pillars of sustainability (environment, society, and economy) and facilitated them in building ecological and socio-environmental knowledge that could form the basis for socio-environmental awareness.

3.2. Results for RQ2

3.2.1. Children’s Pre/Post Understanding of the Target Ecological Concepts

The data analysis indicated an improvement in children’s understanding of the ecological concepts ‘habitat’, ‘forest value’, ‘food chain’ and ‘decomposition’, introduced in the learning environment. As shown in

Table 1. Children’s pre-/post understanding of the target ecological concepts.

Concept	Pre-Responses			Post-Responses
	Naïve	Transitional	Informed	Naïve	Transitional	Informed
Habitat	6/30	18/30	6/30	0/30	0/30	30/30
Forest Value	30/30	0/30	0/30	2/30	5/30	23/30
Food Chain	22/30	7/30	1/30	0/30	2/30	28/30
Decomposition	30/30	0/30	0/30	0/30	1/30	29/30

, most children provided ‘informed’ post-responses to questions about these concepts, whereas their pre-responses were primarily classified as ‘naïve’ or, in some cases, ‘transitional’.

More specifically, in the pre-interviews, the ecological concept with fewer difficulties was the one of ‘habitat’. The children seemed quite familiar with the idea of the forest as the home of animals even before participating in the learning environment, and in the post-interviews, they all gave ‘informed’ responses (Table 1). ‘Forest value’, on the other hand, appeared to be challenging in the pre-interviews. Children’s pre-responses were exclusively ‘naïve’, whereas in the post-interviews most children were able to describe several of the benefits that the forest offers (e.g., oxygen), and several things it protects us against (e.g., floods, wind, noise) (Table 1).

‘Food chain’ appeared challenging in the pre-interviews as well. Children were not able to recognize the consequences of disrupting a link in the chain for the rest of its populations, something that did change after participating in the learning environment (Table 1). Finally, in the pre-interviews, children were not familiar at all with the concept of ‘decomposition’. In contrast, afterward, they were able to describe quite well what happens to the garbage buried in the landfill, depending on its material, and justify their ideas based on the decomposition process (Table 1).

Moreover, Wilcoxon signed-rank tests confirmed statistically significant pre-/post differences for all target ecological concepts (all p < 0.001). Effect sizes were large, ranging from r = 0.83 to r = 0.99, while the 95% confidence intervals of the Hodges–Lehmann estimates ranged from [1.0, 1.5] to [2.0, 2.0], indicating substantial positive shifts in children’s understanding. Detailed statistical results are presented in Appendix E.

3.2.2. Children’s Pre/Post Understanding of the Target Socio-Environmental Concepts

The analysis indicated improvements in children’s grasp of socio-environmental concepts within the learning environment. These included important connections (present–future, local–global, individual–collective), as well as equality, recycling processes, everyday practices for the environment and fellow humans, and sustainability. Wilcoxon signed-rank tests showed statistically significant differences (p < 0.01) between pre- and post-responses, leading to the rejection of the null hypothesis.

Connections and Equality

Table 2. Children’s pre-/post understanding of the target connections and equality.

Concept	Pre-Responses			Post-Responses
	Naïve	Transitional	Informed	Naïve	Transitional	Informed
Future	27/30	1/30	2/30	0/30	2/30	28/30
Present–Future	26/30	3/30	1/30	0/30	4/30	26/30
Local–Global	13/30	17/30	0/30	0/30	4/30	26/30
Individual–Collective	4/30	26/30	0/30	1/30	3/30	26/30
Equality Between Humans	15/30	15/30	0/30	0/30	4/30	26/30
Equality Between Humans and Nature	20/30	10/30	0/30	0/30	1/30	29/30

shows that most children, following participation, provided ‘informed’ responses regarding the concepts of the ‘future’ (28/30), the ‘present–future’ connection (26/30), the ‘local–global’ connection (26/30), ‘individual–collective’ action (26/30), ‘equality between humans’ (26/30), and ‘equality between humans and nature’ (29/30). On the contrary, initial responses were often ‘naïve’ (27/30, 26/30, 13/30, 4/30, 15/30 and 20/30, respectively) or ‘transitional’ (1/30, 3/30, 17/30, 26/30, 15/30 and 10/30, respectively).

More specifically, in the pre-interviews, the connection with fewer difficulties was the one of ‘individual–collective’. The children seemed quite familiar with this even before participating in the learning environment, and in the post-interviews most of them gave ‘informed’ responses (Table 2). The ‘local–global’ connection proved more challenging in the pre-interviews, but many children still seemed to demonstrate an emerging understanding from the beginning (Table 2). The ‘present–future’ connection, on the other hand, appeared to be the most challenging in the pre-interviews. The children’s pre-responses about the idea of the ‘future’ and its connection with the present were mostly ‘naïve’, whereas in the post-interviews most children managed to describe both in more elaborated ways (Table 2). Finally, in the pre-interviews, the idea of ‘equality between humans and nature’ appeared to be more challenging than that of equality between humans alone. However, in both cases, a remarkable number of children already demonstrated promising levels of understanding, and most managed to show a more elaborated understanding after participating in the learning environment (Table 2).

Moreover, the Wilcoxon signed-rank tests indicated statistically significant pre-/post differences for all concepts presented in Table 2 (all p < 0.001). Effect sizes ranged from r = 0.87 to r = 0.93, while the 95% confidence intervals of the Hodges–Lehmann estimates ranged from [1.0, 1.0] to [2.0, 2.0], supporting substantial improvements in children’s socio-environmental understanding. Detailed statistical results are reported in Appendix E.

Recycling Process

The recycling process was associated with learning objectives aimed at familiarizing children with ‘garbage separation’, ‘garbage destination’, ‘landfill operation’, and ‘recycling factory operation’. As shown in

Table 3. Children’s pre-/post understanding of the recycling process.

Concept	Pre-Responses			Post-Responses
	Naïve	Transitional	Informed	Naïve	Transitional	Informed
Garbage Separation	27/30	3/30	0/30	0/30	0/30	30/30
Garbage Destination	22/30	8/30	0/30	0/30	0/30	30/30
Landfill Operation	25/30	5/30	0/30	0/30	0/30	30/30
Recycling Operation	29/30	1/30	0/30	0/30	0/30	30/30

, most children moved from providing ‘naïve’ pre-responses (27/30, 22/30, 25/30, and 29/30, respectively) to ‘informed’ post-responses (30/30 in all cases). These patterns suggest an overall improvement in children’s understanding of recycling-related concepts, including how recycling operates and why it is necessary. This trend is consistent with previous research indicating that young children can meaningfully engage with ‘waste management’ concepts (Debrah et al., 2021; Shutaleva et al., 2020; Ergazaki et al., 2009).

The Wilcoxon signed-rank tests confirmed statistically significant pre-/post differences for all recycling-related concepts (all p < 0.001). Effect sizes ranged from r = 0.92 to r = 0.99, while the 95% confidence intervals of the Hodges–Lehmann estimates were consistently [2.0, 2.0] indicating very substantial improvements in children’s understanding of waste management and recycling processes. Detailed statistical results are presented in Appendix E.

Adoption of everyday practices for the environment and fellow humans

The adoption of everyday practices for the environment and fellow humans with possible socio-economic ramifications (‘recycling’, ‘waste reduction with responsible consumption, i.e., (a) less purchases and (b) larger packages’, and the ‘donations of used goods to economically weaker fellow humans who need support’ as well as ‘forest protection’ and ‘recycling as necessary solution’) has been satisfactorily approached by the learning environment as presented in

Table 4. Categories of children’s responses regarding the adoption of everyday practices for the environment and fellow humans.

Concept	Pre-Responses			Post-Responses
	Naïve	Transitional	Informed	Naïve	Transitional	Informed
Recycling	29/30	1/30	0/30	0/30	2/30	28/30
Less Purchases	30/30	0/30	0/30	0/30	2/30	28/30
Donation of Used Goods to Fellow Humans	15/30	15/30	0/30	0/30	3/30	27/30
Packages	30/30	0/30	0/30	1/30	1/30	28/30
Recovery and Preventive Plan	17/30	13/30	0/30	1/30	3/30	26/30
Recycling as a Solution	28/30	2/30	0/30	0/30	1/30	29/30

. For all these practices, most children (28/30, 28/30, 27/30, 28/30, 26/30 and 29/30, respectively) provided ‘informed’ responses after participation, whereas their initial responses were mainly ‘naïve’ (29/30, 30/30, 15/30, 30/30, 17/30 and 28/30, respectively) or in some cases with ‘transitional’. These findings are consistent with earlier research suggesting that preschool children can understand the rationale for socially and environmentally responsible actions such as recycling and reuse (Kahriman-Ozturk et al., 2012; Ferguson et al., 2021).

Moreover, the Wilcoxon signed-rank tests revealed statistically significant pre-/post differences for all everyday practices examined (all p < 0.001). Effect sizes ranged from r = 0.89 to r = 0.99, while the 95% confidence intervals of the Hodges–Lehmann estimates ranged from [1.0, 2.0] to [2.0, 2.0], indicating substantial improvements in children’s recognition of environmentally and socially responsible practices. Detailed statistical results are reported in Appendix E.

It should be noted that the recorded improvement in the children’s knowledge after their participation in the learning environment does not necessarily imply the adoption of these practices in their daily lives. However, the ability of children to understand the need to adopt such practices can be the first important step in forming responsible attitudes towards the environment and fellow human beings, and possibly behaviors later in life.

Sustainability

As shown in

Table 5. Children’s pre-/post understanding of sustainability as a decision-making tool.

Concept	Pre-Responses			Post-Responses
	Naïve	Transitional	Informed	Naïve	Transitional	Informed
Sustainability	28/30	2/30	0/30	0/30	3/30	27/30

, almost all of the children’s pre-responses to the question on sustainability were ‘naïve’ (28/30), while the majority of post-responses (27/30) were ‘informed’. The category of ‘naïve’ responses was absent in the post-interviews, and nearly all the children (29/30) moved to a higher response category compared to their initial responses. These findings suggest an overall improvement in the children’s ability to consider the three pillars of sustainability (environment, society, economy) when reasoning through simple decision-making scenarios on socio-environmental issues.

The Wilcoxon signed-rank test indicated a statistically significant pre-/post difference in children’s understanding of sustainability as a decision-making tool (p < 0.001). The analysis yielded a large effect size (r = 0.96), while the Hodges–Lehmann estimate indicated a median improvement of two response categories (95% CI [2.0, 2.0]). Detailed statistical results are reported in Appendix E.

Before participating in the learning environment, children either supported or opposed the construction of the entertainment park in the context of the ‘decision-making scenario’ of the interview protocol, focusing on a single factor, either the economic or the environmental. Thus, they either responded, for example, “Yes! They should build it to have money”, or “No…better keep the forest and animals […] it’s ok to not have money”. However, in the post-interviews, children’s responses reflected consideration of multiple factors (i.e., environment, people, and economy) frequently. So, in their post-responses, they claimed, for example, that “They can build it far away. […] they will not scare the animals. […] They have to think the animals and the money and the environment and their health. […] They put rules and build it far away […] they have good future this way. […] with money and happy animals and health.” Thus, after their participation in the learning environment, children appeared able to use sustainability as a decision-making tool.

Familiarizing children with the idea that there are three factors that must be considered equally in the process of decision-making in regard to socio-environmental issues is an important step, the successful completion of which can act as a basis for a deeper exploration of the idea of sustainability at other educational levels (S. Elliott & Davis, 2009). The fact that the learning environment seems to be suitable both for introducing sustainability as a decision-making tool and for introducing related socio-environmental concepts like those presented above reinforces the idea of the feasibility of education for sustainability in early childhood. These findings, in conjunction with the ones on the ecological concepts of the learning environment, support the potential value of integrating biological education with education for sustainability in early childhood.

4. Discussion

The findings indicate that our final learning environment (LE3) potentially contributes to the enhancement of children’s understanding of both ecological and socio-environmental concepts. For most of the concepts introduced in LE3, there was a shift from lower-level responses (naïve) to higher-level responses (informed), indicating a pattern of conceptual development that may be associated with participation in structured learning activities.

Regarding ecological concepts, improvements were observed in children’s understanding of ‘habitat’, ‘food chain’, ‘forest value’, and ‘decomposition’. Even for ‘decomposition’, a concept often described as challenging for young learners, most children progressed toward more satisfactory explanations. This suggests that appropriately designed activities—integrating predictions, hands-on empirical testing, guided discussions—may support preschool children in building essential ecological knowledge (Ardoin & Bowers, 2020; Dimitriou & Christidou, 2007; Ergazaki & Andriotou, 2010; Ergazaki et al., 2009; Huggins & Evans, 2018; Somerville & Williams, 2015).

Similarly, the learning environment appeared to support children’s understanding of socio-environmental concepts, including the connections of ‘present–future’, ‘local–global’ and ‘individual–collective action’, as well as ideas related to ‘human–nature equality’, ‘human–human equality’, ‘recycling’, ‘sustainability’, and ‘everyday practices for environmental and social well-being’ (Zguir et al., 2021; Engdahl & Furu, 2022). The findings provide empirical evidence that combining biological education with education for sustainability (EfS) can be a productive and meaningful approach in early childhood education (S. Elliott et al., 2020; J. Davis & Elliott, 2023). Furthermore, the findings highlight young children’s potential to engage not only with ecological ideas that may help them to start building a better understanding of the interactions in nature, but also with socio-environmental ideas that may help them to start recognizing the ‘nature–society–individual’ interconnectedness. This aligns with Kahriman-Ozturk et al. (2012), who demonstrated that young children have the capacity to comprehend socio-environmental ideas related to the three pillars (environmental, sociocultural, and economic) of sustainability.

Although sustainability is a key reference point in EfS and early childhood EfS, it remains a complex construct that some scholars may consider as developmentally too advanced for young children due to its multidimensional nature (Collado et al., 2020; Ferguson et al., 2021). The present findings, however, suggest that when introduced to sustainability through structured learning experiences, it is possible for preschoolers to begin to engage with it as a decision-making framework (Lam et al., 2020; Wooltorton et al., 2020). A process of didactic transformation can result in age-appropriate versions of challenging concepts that children can explore and hopefully internalize. These findings are also broadly consistent with the theoretical perspectives that informed the design of LE3, namely constructivism, the possible futures approach, the problem seekers–problem solvers–action takers approach, and the problem-posing approach, all of which emphasize children’s active engagement with meaningful socio-environmental issues, future consequences, and opportunities to evaluate possible actions.

In LE3, the children engaged with a decision-making scenario that required them to simultaneously consider environmental, human, and economic factors while resolving conflicts of interest. The shift from naïve to informed responses indicates that they were able to grasp sustainability as a practical tool for reasoning and decision-making. This may reflect an emerging ability to think critically about trade-offs and consequences in sustainability-related decisions when participating in carefully structured educational activities (Taimur & Sattar, 2020; Campbell & Speldewinde, 2022).

Based on these findings, we suggest that introducing young children to sustainability while allowing them to explore related socio-environmental and ecological concepts could be carried out by drawing on the CAT strategy, the design theory we developed within this study. The CAT strategy frames sustainability as a decision-making tool, guiding children through a structured learning process consisting of four interconnected stages: (1) defining a simplified socio-environmental problem within children’s cognitive capacity alongside a non-sustainable solution to trigger engagement; (2) evaluating the unsustainable solution by projecting its consequences into the future and recognizing potential risks to both humans and the environment; (3) returning to the present to revise the unsustainable solution using newly acquired ecological and socio-environmental knowledge; and (4) exploring the revised solution and its implementation while reflecting on personal responsibility. In sum, the idea of sustainability gets highlighted when children shift from the present to the future and vice versa, first putting it together and then applying it as a decision-making tool.

Our findings suggest that the CAT strategy can create learning environments where the concept of sustainability can be meaningfully introduced to young children along with other socio-environmental concepts as well as ecological ones. So, it is a strategy that can bring together biological education and EfS with the aim of promoting ecological understanding and socio-environmental awareness in early childhood education. Thus, it may inform future curriculum development and teacher education initiatives aiming to strengthen ECEfS, especially in countries like Greece where research and practice in this field remain limited despite the documented environmental challenges (Sakellariou & Banou, 2022; Petkou et al., 2025).

The implications of these findings should be considered at different levels. First, the study provides evidence that preschool children can engage with age-appropriate ecological and socio-environmental concepts, including simplified approaches to sustainability. Second, the findings suggest that participation in LE3 was associated with improvements in children’s interview responses within the specific context of this study. Third, the CAT strategy should be viewed as a design theory whose broader transferability remains to be examined through implementation in different educational settings, age groups, and cultural contexts. Therefore, the present study offers an initial empirical articulation of the CAT strategy and provides evidence of its potential value, while further research is needed to examine its applicability beyond the context in which it was developed.

Limitations and Future Research

While the study showed encouraging results, several limitations should be acknowledged. Children seem to have developed an understanding of the importance of acting for the environment, but this does not necessarily indicate that they will adopt environmentally friendly behaviors in their present or future daily life. Participation in the learning environment was associated with shifts in children’s conceptual understanding; however, the study did not assess whether these newly acquired perspectives would persist over time or influence real-world decision-making in the future. As knowledge and awareness alone may not necessarily lead to consistent pro-environmental actions, longitudinal studies would be needed to explore whether children who demonstrate an essential understanding of sustainability at a young age exhibit environmentally responsible behaviors later in life (Debrah et al., 2021; Shutaleva et al., 2020).

A critical limitation concerns construct validity and the interpretation of what the interview tasks actually assessed. Although the interview protocols were designed to explore children’s understanding of ecological and socio-environmental concepts related to sustainability, the findings may also reflect their verbal responsiveness to scaffolding. In the sustainability task, in particular, children who reconsidered their initial choices were asked additional probing questions to explain their reasoning. Rather than an unintentional bias, such prompting was a deliberate methodological choice aligned with qualitative interviewing techniques in early childhood research through the use of non-leading follow-ups to clarify underlying reasoning. Nevertheless, the potential influence of this conversational process on response patterns cannot be entirely excluded. In addition, the interview scenarios required children to reason about hypothetical situations shortly after the intervention. Therefore, the results should be interpreted as evidence of children’s short-term, scenario-specific reasoning within a scaffolded context, rather than a comprehensive assessment of a broader, independent understanding of sustainability.

While the substantial improvements regarding many of the target concepts are encouraging, they should also be interpreted cautiously, as several factors may have contributed to them in addition to participation in LE3. First, the questions within the forest and decomposition protocols were identical in the pre- and post-tests, and therefore repeated exposure and growing familiarity with them may have streamlined children’s performance. Second, the alignment between instructional activities and assessment tasks may have played a role, as well. However, it should be noted that the assessment tasks were not mere repetitions of the learning activities. Although targeting the same concepts and sharing a similar structure with the learning activities, some assessment tasks (e.g., the sustainability task) utilized contextually different scenarios, thus requiring more than simple recall. Third, the coding scheme transformed a range of qualitative responses into three ordered categories, which may have amplified the visibility of conceptual shifts.

Finally, since we conducted a case study rather than an experiment with a control group, it is not possible to determine whether similar improvements would have emerged through alternative instructional approaches over the same period. Consequently, the observed improvements should be interpreted as being associated with the present learning environment rather than as evidence of its superiority over others. In addition, the participants were relatively few (N = 30) and recruited via convenience sampling.

Taken together, these limitations suggest that the findings provide evidence of emerging ecological and socio-environmental reasoning within the context of the interview tasks, rather than definitive evidence of stable, generalized understanding. Future research should incorporate delayed post-tests, additional assessment formats, and comparison groups to examine the durability and robustness of these understandings.

5. Conclusions

Despite its limitations, the present study contributes to ongoing discussions about the feasibility of education for sustainability (EfS) in early childhood. Overall, the findings suggest that young children can engage with age-appropriate sustainability-related concepts when these are introduced through carefully designed learning environments that combine ecological knowledge, socio-environmental reasoning, and opportunities for decision-making. The findings also indicate that integrating biological education with EfS has the potential to support children’s understanding of ecological concepts.

Thus, the study points to the potential value of strengthening the connections between biological education and EfS in early childhood settings. Socio-environmental problems can serve as meaningful contexts for biological learning, while biological education can, in turn, facilitate children’s engagement with socio-environmental issues. This reciprocal relationship may help educators introduce ecological and socio-environmental ideas related to sustainability in ways that are accessible to young children.

Within this context, the CAT strategy developed in the present study may represent a promising approach for connecting ecological knowledge, socio-environmental reasoning, and action-oriented thinking within early childhood education. Nevertheless, the CAT strategy should be regarded as a design theory that requires further testing and refinement through implementation in different educational, cultural, and age-group contexts.