A qualitative study on Chinese primary school EFL teachers’ beliefs about incorporating intercultural competence into foreign language teaching

Abstract

Intercultural competence has become one of the important goals of foreign language education. The potential and value of foreign language education on students' intercultural competence (IC) has been widely recognized by academia. Currently, most of the research on intercultural foreign language teachers in China focuses on university teachers, with little attention paid to primary school EFL teachers. However, the cultivation of IC is a staged and continuous process which cannot be achieved in one stroke. Therefore, it is necessary to include primary school EFL teachers in the study of IC cultivation. This paper presents data on Chinese primary school EFL teachers' beliefs about incorporating IC into foreign language teaching. Specifically, their understanding of culture, IC, and intercultural teaching practices are investigated through interviews. The interview transcriptions were analyzed using thematic analysis. The research found: 1. Chinese primary school EFL teachers generally hold an essentialist view of culture; 2. Teachers emphasize the attitudinal dimension of IC; however, they also exhibit a tendency to oversimplify IC or perceive it as a higher-order skill than language proficiency, hence deeming it unsuitable for cultivation at the primary school level; 3. Most cultural teaching practices are teacher-centered, focusing on background knowledge-style introduction. In general, teachers’ intercultural teaching practices align with their cultural outlook. At last, the study explores two suggestions for promoting intercultural foreign language teaching: 1. Supporting primary school EFL teachers in updating their language and culture concepts system; 2. Encouraging teachers to reflect on their daily teaching practices as a major opportunity to promote the development of intercultural foreign language teaching.

1. Introduction

Intercultural competence (IC) is generally regarded as an individual's ability to communicate effectively and appropriately in intercultural situations, based on one's intercultural knowledge, skills, and attitudes [1,2]. With the continuous development of globalization, developing students' IC has become one of the important tasks of education[[3], [4]]. Due to the inherent connection between language and culture, foreign language education has emerged as a crucial arena for the cultivation of IC, with language teachers playing a pivotal role in this endeavor.

However, IC cannot be acquired by learners automatically during their experiences learning a foreign language or staying abroad [5]. Rather, it necessitates proactive efforts from language teachers to equip their students with the set of attitudes, knowledge, and skills needed in intercultural communication. This means language teachers must first become intercultural competent individuals themselves [6,7], which is a challenging endeavor. Additionally, they should acquire new knowledge in areas such as discourse analysis, intercultural pragmatics, and content analysis theories, thus preparing themselves for these demanding tasks [8].

Yet, studies have found that despite the widespread acknowledgment of the significance of intercultural education [9,10], front-line teachers still find themselves perplexed about how to cultivate students’ IC [8,[11], [12], [13], [14]]. Many factors contribute to this challenge, ranging from constraints such as limited classroom time [10,15] to deficiencies in IC training among teachers themselves [8,9].

In the realm of research concerning intercultural foreign language teachers, teachers' beliefs regarding this area stand out as a focal point. This emphasis stems from previous studies highlighting the significance of teachers' beliefs, as they influence various facets of teaching practices. Scholars believes that teachers' beliefs have a bigger influence on their teaching plans, teaching decisions, and classroom practices than that of teachers' knowledge [16]. Mercer & Kostoulas also pointed out that belief has an emotional filtering effect on the absorption of new ideas and new knowledge, and teachers' beliefs will redefine or change their understanding of new ideas [17]. However, within the extensive body of research on teachers beliefs toward intercultural foreign language teaching (IFLT), there is limited research exploring how teachers define related concepts. Understanding how teachers conceptualize IFLT, specifically their comprehension of culture and IC, as well as their understanding of the cultivation of IC in foreign language education, constitute a crucial component of teachers' beliefs in IFLT. Moreover, teachers' beliefs are intricately linked to their teaching practices [[18], [19], [20]]. Therefore, this study intends to employ an interview approach to investigate how primary school EFL teachers conceptualize IFLT, and whether and how their understanding of this concept influences their day-to-day teaching practices. The researchers believe that delving into this question can contribute to a better understanding of potential factors influencing teachers’ engagement in IFLT. Furthermore, it aims to provide evidence-based insights for future teacher education and professional development.

2. Literature review

2.1. Culture and intercultural competence in English language teaching

Culture is one of the most complex terms in the English language [21]. In terms of theoretical evolution, the academic discourse on the definition of culture has undergone a transition from structuralism (essentialism) to constructivism and then to deconstructionism. Prior to the 1990s, the international scholarly community generally concurred that culture referred to the shared and unchanging products, ideas, and behaviors within a particular group [[22], [23], [24]]. After the 1990s, the fields of language and second language acquisition experienced a ‘sociocultural shift’ [25]. Scholars who espoused social constructivist views criticized essentialist perspectives of culture, arguing that they overlook the dynamic nature of culture and individual uniqueness. The constructivist perspective posits that culture is dynamic and negotiated through discourse, being both created and challenged by it. Kramsch collectively labels the structuralist and constructivist perspectives as the ‘modernist viewpoint’. During this period, the prevailing belief was that culture had clear boundaries based on regions, races, or ideologies. People can engage in intercultural comparisons, such as comparing verbal and non-verbal behaviors between their own culture and the target culture with which they are interacting [26].

With the onset of economic globalization in the late 1980s, commercial interests began to surpass national interests, emerging as a new driver of communicative competence. Becoming bilingual or multilingual reflects individuals’ symbolic potential and their capacity to construct their own identities [27]. The evolving meanings of language, culture, and communication must be interpreted through a postmodernist perspective. In the era of globalization, communities have become too heterogeneous and complex to establish clear-cut behavioral norms that must be adhered to for smooth communication. Pragmatic appropriateness must now be negotiated case by case [26].

Furthermore, due to increasing international communication and the deepening of globalization, influenced by research advancements in World Englishes [28], English as an International Language [29], and English as Lingua Franca [30,31], the field of English language education has seen debates emerge regarding which variety of English should be taught. The once-prevailing standard of the native speaker has come under scrutiny, and the question of which language corresponds to which culture has also become a new focal point of controversy in English language teaching. Intercultural speakers have begun to replace native speakers as the target of foreign language education [[32], [33], [34], [35], [36]]. The cultivation of IC has been explicitly incorporated into foreign language education policies in numerous countries, including China.

An intercultural speaker is defined as a foreign language user who possesses some or all of the sub-elements of IC [33]. IC encompasses five sub-elements: knowledge, skills of interpreting and relating, attitudes of curiosity and openness, skills of discovery and interaction, and critical cultural awareness [2,32]. An intercultural speaker is neither an imitation of native speakers who identify exclusively with one language and one ethnic group, nor is it a bilingual/multilingual individual who separates language and identity. Instead, it refers to someone who can perceive and flexibly coordinate linguistic and cultural differences between their mother tongue and the target language [37], serving as a bridge for communication between different languages and cultures [34].

2.2. Intercultural foreign language teaching (IFLT)

Language and culture are inseparable, and foreign language instruction necessarily involves teaching culture. Whether willingly or not, foreign language instructors will inevitably encounter culture in the foreign language classroom. However, the way cultural elements are handled in foreign language instruction -- whether passively, incidentally, and haphazardly or actively, consistently, and systematically -- can significantly impact instruction effectiveness. Introducing the concept of intercultural foreign language teaching (IFLT) aims to comprehensively reexamine conventional foreign language teaching practices from an intercultural perspective.

In brief, IFLT can be defined as foreign language teaching with the goal of cultivating IC [38]. Traditional foreign language instruction primarily emphasizes language proficiency or communicative skills, often neglecting or undervaluing IC. IFLT aims to integrate foreign language teaching and cultural education, facilitating the concurrent development of students’ language proficiency and IC.

While aspirations may be noble, the translation into practical implementation frequently falls short. Despite the Chinese government's emphasis on cultivating students' IC as a key objectives in foreign language education, cultural teaching remains consistently underdeveloped, particularly at the primary education stage. Scholars have critiqued English language instruction at the elementary education level for its neglect of humanistic aspects [39]. Most English language teachers tend to prioritize the communicative and instrumental aspects of language, neglecting its cognitive and socio-cultural dimensions [40]. Moreover, while research in IFLT at higher education levels has made significant strides [41] [42,43], there is a noticeable dearth of research on fostering young learners' IC [38,44].

However, previous studies have already affirmed the necessity and feasibility of integrating intercultural education into elementary education. Remarkably, children as young as three to four years old commence the categorization of individuals based on race and ethnicity, leading to evident inter-group comparisons [45,46]. It is during childhood that stereotypes begin to take shape, solidifying their presence through adolescence [47]. Developing IC in children not only enhances their sense of identity but also heightens their sensitivity to other cultures, fostering an open and inclusive attitude among them [48,49]. Furthermore, Zhang and Zhou's meta-analysis found a significant decline in the strength of intervention effects on students' IC from K-12 to tertiary education, once again underscoring the importance and necessity of implementing IFLT at the elementary level [50].

2.3. Intercultural foreign language teaching (IFLT) in Chinese primary schools

Since the implementation of the Reform and Opening-up policy in 1978, China has consistently strengthened its global connectivity. Notably, in 1982, the Chinese Ministry of Education formally endorsed English as the first foreign language for school education, catalyzing rapid advancement nationwide in English education. Subsequently, in 2001, the Ministry of Education mandated the inclusion of English courses starting from the third grade of primary school, with provisions for early commencement in certain regions. Consequently, English education has permeated various educational tiers in China, ranging from compulsory education to doctoral studies, with an estimated populace of English learners and users exceeding 300 million [51].

English has become an indispensable component of educational curricula at various levels over the past four decades. As a result, ongoing reforms in the English curriculum have been undertaken to align with the evolving demands of contemporary times [52]. In terms of IC, an initial proposal was made in 2000 to enhance students’ comprehension of cultural differences and global awareness through English education. A significant milestone in English education reform in China occurred in 2011 with the conspicuous adoption of English Curriculum Standards for Compulsory Education (hereafter referred to as the Curriculum Standards), replacing the previous syllabus. The Curriculum Standards outline mandates encompassing not solely knowledge, competence, and skills but also emotions, attitudes, values, and intercultural awareness. Significantly, these standards assign equal importance to both intellectual and non-intellectual requisites. Consequently, the objectives of the English language curriculum transcend the conventional instrumentalist approach grounded solely in knowledge orientation. Instead, they underscore the intimate nexus between language and culture, necessitating teachers to adeptly navigate this relationship in their instructional endeavors.

According to the Curriculum Standards, the English course should cultivate students' core competencies from four aspects: language proficiency, cultural awareness, thinking qualities, and learning abilities. From elementary school to junior high school, each aspect of core competencies has three different levels of objectives specified. By the time of elementary school graduation, students should be able to achieve level two, while by the time of junior high school graduation, they should reach level three. Among these aspects, cultural awareness refers to students' understanding of both domestic and foreign cultures and their appreciation of outstanding civilizational achievements. It embodies students' intercultural cognition, attitudes, and behavioral choices in the new era. Specifically, it stipulates the levels of students’ attainment in compulsory education regarding comparison and judgement, adaptation, communication, perception, and internalization.

An analysis of the latest Curriculum Standards reveals a growing emphasis on balancing instrumental and humanistic aspects in English instruction, diverging from the traditional focus solely on instrumental functions. The cultivation of students' IC has emerged as a pivotal pedagogical objective in English language education in China, beginning from elementary education. This emphasis aims to address students’ personal growth needs, equipping them with the necessary skills to navigate the complexities of living in a diverse and constantly evolving multicultural environment.

2.4. Teachers’ beliefs and practices of intercultural foreign language teaching

Facilitating the transition from conventional language instruction to intercultural foreign language teaching (IFLT) requires language instructors to play a pivotal role as catalysts for change. Therefore, understanding their perspectives and positions becomes imperative, especially as foreign language education increasingly adopts broader objectives. It is recognized that teachers' intercultural sensitivity and IC can influence students’ development in this regard [53]. Consequently, language instructors must themselves acquire IC and prepare for the emerging challenges of the modern era [6,7].

Continuing this line of inquiry, significant attention has been directed towards exploring educators' beliefs and attitudes concerning IFLT. Representative Chinese surveys on teachers' beliefs and attitudes towards IFLT [11,13,14], alongside international research [10,12], indicate that foreign language teachers' beliefs, both domestically and abroad, have remained largely unchanged. While most teachers theoretically or emotionally acknowledge the pivotal role of IC in foreign language education, they hold uncertain attitudes towards integrating the cultural dimension into language teaching. Many admit they are ill-prepared for such a challenging transition [54]. This uncertainty leads to varying interpretations of policies and harboring of misconceptions about IC [11,55], with teacher-centered, language knowledge-focused instructional models remaining predominant. Teaching practices still predominantly focus on transferring factual cultural knowledge [56,57]. Teachers often utilize culture merely as static products or knowledge, regarding it as a short-cut to developing students’ IC [58,59]. Additionally, due to a lack of awareness and knowledge of intercultural education, teachers often prioritize English language norms based on native speakers [60] and tend to link cultural content directly to English-speaking countries [61].

2.5. Gaps in the literature review

Both domestic and international research has shown that primary education is a crucial domain for nurturing IC through foreign language education. Elementary school students, who are still developing cognitive abilities, are significantly influenced by their teachers. The pivotal role of teachers in facilitating the development of IC among elementary school students is supported by other research [45,46]. Despite the existing body of research on IFLT, there is relatively limited focus on research related to the elementary education stage [38]. The majority of research on IFLT teachers has primarily focused on university teachers [62,63], with a smaller subset examining secondary school teachers [10,12]. There is a notable scarcity of research specifically targeting primary school EFL teachers. Furthermore, in terms of research methodology, most previous investigations into foreign language teachers' beliefs and practices related to IFLT have employed questionnaires [10,11,13]. While the questionnaire method allows for obtaining a large amount of data about teachers' opinions on IFLT, it restricts teachers' answers to the options provided, making it difficult to obtain insightful responses. Additionally, these surveys targeting teachers have predominantly focused on teachers' own IC [9], their attitudes towards IFLT [13], the affecting factors [64], or their preparedness for IFLT [54]. There is limited research that specifically delves into teachers’ cultural outlook and the impact of these perspectives on their teaching practices.

Based on the discussion above, the objectives of the current research are twofold: 1) to obtain a qualitative understanding of culture and intercultural competence in a sample of Chinese primary school EFL teachers; 2) to examine how these understandings influence their teaching practices of IFLT.

Accordingly, this study aims to answer the following three research questions.

• 1.How do in-service primary school EFL teachers define culture and intercultural competence?
• 2.What intercultural teaching practices do teachers endorse?
• 3.How do teachers' understanding of culture and IC influence their intercultural teaching practices?

3. Methods

3.1. Research design

The current study is the second phase of the investigation project on Chinese primary school EFL teachers' beliefs and practices in IFLT (hereafter referred to as the project). The project employed an explanatory mixed methods research design. An explanatory mixed methods research design refers to ‘the researcher begins by conducting a quantitative phase and follows up a specific result with a subsequent qualitative phase to help explain the quantitative results’ [65]. In the initial phase, quantitative data were collected through an online questionnaire, while the subsequent phase entailed acquiring qualitative data through interviews and classroom observations.

Initially, the project utilized a quantitative questionnaire to collect data concerning teachers’ beliefs and practices in IFLT. This survey aimed to offer a comprehensive overview of the sampled population and identify patterns or trends. The questionnaire responses were subsequently subjected to analysis employing descriptive and inferential statistical methods, thereby providing quantitative insights into the prevalence and distribution of various beliefs and practices [65,66].

Based on the findings from the quantitative phase, we developed a semi-structured interview framework and provided guidance for classroom observations. Subsequently, a subset of participants, identified by their expressed interest in participating in the follow-up study and provision of contact information, were selected for further formal exploration using qualitative methodologies. Semi-structured interviews were utilized to probe deeply into teachers' beliefs, potentially obscured in the questionnaire survey, as well as to uncover the underlying rationales and the personal and contextual determinants shaping teachers’ beliefs and practices. Furthermore, classroom observations were employed to observe actual teaching practices and examine the implementation of IFLT within authentic educational settings. The qualitative data gathered from these interviews and observations underwent thematic analysis, facilitating the identification of salient themes and recurrent patterns that contribute to addressing the research inquiries [65,67].

This constitutes the research design of the entire project. The aim of this paper is to investigate how teachers comprehend key concepts related to IFLT and whether such comprehension influences their teaching practices. Hence, only the interview data from the second phase of the project is utilized in this paper.

3.2. Instrumental validity

The current study primarily employed a qualitative semi-structured interview research method. As previously mentioned, the interview outline was formulated following the analysis of questionnaire results. Specifically, we developed the interview guide based on some intriguing or unexpected findings from the questionnaire survey, or those deemed necessary for in-depth exploration by the three authors. For instance, in the online questionnaire, we queried teachers about their perspective on the focal point of IFLT to foster children's IC. We provided four options: offering cultural background knowledge and vocabulary, contrasting Eastern and Western cultures, providing multimedia resources, and recommending relevant cultural materials. The results indicated a similar distribution of responses across the four options, suggesting a lack of consensus among teachers regarding the focal point of IFLT; each teacher held their own interpretation. This realization prompted us to investigate how teachers conceptualize IFLT, leading us to design the interview question: ‘How do you conceptualize intercultural competence?’

In constructing the interview guide, we generated a table delineating intriguing and unexpected findings from the quantitative results. Subsequently, interview questions were crafted based on these findings, a collaborative effort undertaken by all three authors. Following the preliminary design of interview questions, a panel was convened to independently assess the relevance of the interview inquiries. The panel comprised two professors specializing in intercultural studies, one professor with expertise in qualitative research methods, and two exemplary elementary school EFL teachers with 24 years of front-line teaching experience. The panel members assessed the adequacy of interview questions in addressing the specific outcomes derived from the quantitative data. In accordance with Lynn's suggestions to avoid neutral responses [68], a 4-point Likert scale ranging from no relevance to strong relevance was adopted instead of presenting an odd number of options. Considering the panel's size, Lawshe's formula [69] was employed to establish a content validity ratio (CVR) threshold, indicating the point at which the panel's consensus achieves statistical significance at the alpha level of 0.05. As a result, questions scoring below this threshold were eliminated, thereby improving the overall content validity of the primary interview instrument.

Following the development of the initial interview guide, we recruited a total of three elementary school EFL teachers for a pilot study. These three teachers were selected through purposeful sampling. Each teacher represented a different career stage -- early career, mid-career, and late career -- with corresponding professional titles of junior, mid-level, and senior. Through purposeful sampling in the pilot study, we made modifications to certain statements within the interview questions. For instance, in the initial version, we used the term ‘conceptualize’, as in ‘How do you conceptualize intercultural competence?’ All three teachers indicated that the term ‘conceptualize’ seemed unfamiliar to front-line teachers and felt like an overly formal question to which they might be hesitant to respond. Therefore, for the formal interviews, we revised this question to ‘How do you understand intercultural competence?’

In summary, this study primarily utilized a semi-structured interview approach. During the formulation of the interview guide, we extensively drew upon the emerging findings from the questionnaire survey, as well as those deemed worthy of further exploration by the authors. Additionally, during the process of outlining design, we also employed expert group assessments and pilot studies to continuously refine and revise the interview outline, ensuring its validity and reliability. Following validation through expert group assessments and pilot studies, we ultimately established the formal interview guide (see Appendix).

3.3. Participants

In the first phase of the online survey, researchers primarily recruited participating teachers through the Primary Teacher Education Alliance. This alliance, initiated by local universities and education administrative departments in central China, comprises 71 primary schools, ranging from prestigious urban primary schools to remote rural institutions. Initially, researchers contacted English teaching research group leaders from the 71 alliance schools through professional networks and distributed study information sheets online. Subsequently, these leaders forwarded the information sheet links to all English teachers within their schools, encouraging them to participate in the study.

In the end, 93 teachers participated in the first phase of the questionnaire survey. At the end of the questionnaire, teachers were asked if they were willing to participate in subsequent interviews and classroom observations; those willing to engage in further research were invited to leave their contact information. Fourteen teachers expressed their willingness to participate and provided their contact details. Subsequently, researchers established contact with each teacher, providing detailed information about the study's content and objectives. After coordinating interview times, a total of 10 teachers ultimately agreed to and completed the interviews. The researchers identified the ten teachers as T1 to T10 to protect their privacy. The personal information of the ten interviewees is shown in Table 1.

Table 1.

Personal information of ten interviewees.

Identifier	Age	Gender	Teaching Experience	Educational Background	School Community
T1	22	Female	0.5 year	Bachelor's degree	county
T2	46	Female	23 years	Bachelor's degree	county
T3	22	Female	0.5 year	Bachelor's degree	Provincial capital city
T4	44	Female	22 years	Bachelor's degree	county
T5	30	Male	7 years	Bachelor's degree	city
T6	34	Female	12 years	Bachelor's degree	Provincial capital city
T7	22	Male	1 year	Bachelor's degree	Provincial capital city
T8	25	Female	5 years	Bachelor's degree	county
T9	25	Female	4 years	Bachelor's degree	Rural area
T10	24	Female	2 years	Bachelor's degree	Rural area

Ten interviewees share similar educational backgrounds, all holding bachelor's degrees. Their ages range from 22 to 46 years old, with teaching experience varying from half a year to 23 years. Among them, four teachers reside in urban areas, and four in counties. Among the 10 interviewees, only 2 are male. However, this gender ratio aligns with the current gender distribution among primary school teachers in China. According to the data released by the Chinese Ministry of Education in 2020, male teachers constitute 28.83 % of primary school teachers in China, with even fewer male teachers in the field of English.

As our interview participants were drawn from teachers who responded to the questionnaire and expressed willingness to participate in subsequent research, we did not have the option to select interviewees and thus could not employ methods such as the Stopping Criterion to ensure data saturation. Considering the similarities among our study participants and the depth of our interviews conducted with a total of 10 primary school EFL teachers, we find support in existing qualitative research literature. Studies indicate that saturation can be achieved with 9–17 interviews [70], with thematic saturation requiring even fewer interviews, covering over 90 % of themes with just 9 interviews [[71], [72], [73]]. Therefore, we believe that conducting 10 interviews would not compromise the reliability of our conclusion.

3.4. Data collection and analysis

The researcher contacted each participant several times by telephone or by email in advance in order to schedule a suitable time and place for the interview. It is also important to build a trusting and friendly relationship with the participants, which is helpful in achieving high-quality data [74,75]. Such relationships encourage participant comfort, openness, and reduced response bias. Additionally, they foster trust, enabling participants to share sensitive information and diverse perspectives, ultimately enriching the datasets with contextual insights.

An interview was conducted at a mutually convenient time. Taking into account time constraints, we conducted only one formal interview with each teacher, comprising a total of 16 questions. Depending on the length of teachers’ responses, the duration of interviews ranged from 45 min to 1.5 h, with an average interview length of approximately 1 h. Ultimately, this process generated a transcription of approximately 90,000 words. The interviews were audio recorded and conducted in Chinese, as it is easier for individuals to express complicated ideas, understandings, values, beliefs and practices using their mother tongue. The interview was guided by, but not restricted to, the listed questions. Free exploration of topics that arose during the interview process was also allowed. During the interview, stories and personal experience about intercultural communication are encouraged, providing researchers with an opportunity to derive meaning from the authentic context of these stories [76].

The qualitative data obtained from the interviews were subjected to thematic analysis, allowing for the identification of key themes and patterns that shed light on the research questions [65,67]. The six phases are: familiarizing with data, generating initial codes, searching for themes among codes, reviewing themes, defining and naming themes, and producing the final report. The first author served as the primary transcriber, while coding was collaboratively conducted by three authors using Nvivo software. The coding process was organized by the first author, who facilitated collaborative coding of a transcript by all three authors. Upon encountering discrepancies, consensus was reached through discussion. Subsequently, each author independently completed coding for the remaining transcripts. Finally, the first author checked inter-rater reliability on the three sets of codes. Consistency among the coding by the three authors exceeded 95 %.

In the process of coding, seeking recurring themes within a vast amount of text is not a simple task. Therefore, we adhered to the principles of ‘structural coding’ [77], labeling passages with terms relevant to the research questions. For example, our central research question focuses on the beliefs, practices, and influencing factors of Chinese primary school EFL teachers regarding IFLT. Consequently, we established three secondary codes under IFLT: IFLT beliefs, IFLT practices, and influencing factors. These secondary codes facilitated the organization of transcript text into domains to construct relevant themes. These domains were derived from interview guide questions based on the research questions. This approach significantly reduced the number of codes while providing a contextual framework to develop themes or theme clusters closely associated with the research questions.

In certain instances, experiences, narratives, etc., we employed a ‘descriptive coding’ approach to construct labels that convey the essence of interview content. For instance, when a teacher mentioned various activities organized by the school in proximity to the Mid-Autumn Festival, such as collecting poetry related to the festival, discussing its origins, and presenting traditional customs associated with it, we coded it as ‘IFLT practices -- after-class activities’. Through this method, we condensed the lengthy and complex responses provided by participants into repeatable thematic codes.

4. Results

4.1. Teachers’ understanding of culture

Before the 1990s, the international academic community broadly concurred that culture referred to a set of shared and unchanging products, concepts, and behavioral patterns within a given group, a perspective commonly referred to as the essentialist/structural cultural outlook [[22], [23], [24]]. The data collected in this study show that the essentialist cultural outlook predominantly prevails among primary school EFL teachers. In general, their definitions of culture can be categorized into three groups: those who view culture as ‘products’ (n = 5), those who perceive culture as ‘lifestyle’ (n = 4), and those who consider culture as ‘education’ (n = 1). The first two categories of teachers overwhelmingly dominate in terms of quantity.

A commonly held definition conceptualizes culture as ‘products’ — either intangible intellectual products, tangible material products, or a combination of both. Some teachers emphasize the ‘intellectual’ dimension of culture, while others contend that culture encompasses both intellectual and material products. Two representative definitions are as follows:

Culture … you know, I think different countries and different ethnic groups all have their own unique cultures, right? It can involve aspects related to the mind, like art and philosophy, and it can also involve material aspects, such as clothing, food, shelter, and daily routines. For instance, the different types of clothing people wear in various countries, their eating habits, and their dining etiquette would fall under material culture. On the other hand, things like art and philosophy belong to the realm of spiritual culture. (T7)

I think culture is the understanding and knowledge we develop as humans during our ongoing evolution. It tends to be more focused on the intellectual and spiritual aspects rather than the material ones. (T1)

Teachers who adhere to this belief often employ terms like ‘local customs’ or ‘customary practices’ when defining culture or providing examples. From such instances, the enduring popularity of the ‘4F’ cultural definition — comprising foods, fairs, folklore, and statistical facts [78] — among primary school EFL teachers becomes apparent. Furthermore, teachers of this orientation frequently perceive culture as a static phenomenon or as products associated with a specific nationality or country, mapping culture onto national boundaries, as previously cited: ‘different countries and different ethnic groups all have their own unique cultures’. These educators typically view cultural instruction as the dissemination of language-related cultural information or knowledge, with individuals seen as representatives of a broader domain [56,79].

Another group of teachers view culture as ‘life’:

Culture is the life of the local people, the current life and their historical life, the kind of spirit that has been passed down. (T3)

Culture is our basic daily life, including food, clothing, housing, and transportation — all aspects of daily life. (T6)

Following the categorization outlined by cultural anthropologists [80], defining culture as ‘life’ or ‘way of life’ falls under the normative cultural definition. Risager argues that defining culture as ‘the whole’ or ‘everything’ serves as a shortcut to avoid conceptual complexity and multidimensionality [59], a viewpoint critiqued by Nieto for oversimplifying the intricate nature of culture [81].

There was one participant who gave an isolated definition of culture, regarding culture as ‘deep knowledge’:

You have knowledge, you may not necessarily understand culture. If you have culture, it must be a level higher than knowledge. You have something in your heart, and you can externalize it; that’s culture. It means … I have learned something, and I can use this thing to educate others. That’s culture. (T2)

This is a relatively archaic definition of culture, originating in the 18th century [21]. It was also prevalent in early Western languages, denoting concepts such as ‘civilization’ or ‘refinement of the mind,’ especially in the context of education, culture, and art [82]. This form of culture is often referred to as Big Culture (Big C).

It is worth mentioning that nearly all participants struggled to provide a definition of culture. They took considerable time to find the right words to express their understanding of culture. Although each participant eventually offered a definition, three of them expressed, ‘I never thought about this question’ (How do you understand culture?) in the interview.

In conclusion, while the definitions provided by participants were diverse and intricate, the majority exhibited essentialist characteristics. This perspective views culture as the shared and unchanging products, ideas, and behaviors within a group. In this study, most teachers define culture as ‘life’ or ‘products,’ suggesting that essentialist views remain prevalent at different levels.

4.2. Teachers’ understanding of intercultural competence (IC)

Based on the results of data analysis, teachers’ understandings of intercultural competence (IC) can be broadly categorized into two major groups. The first group perceives IC as the ability to comprehend different cultures, show respect for cultural differences, and, in some cases, employ critical thinking skills (n = 5). The second group views IC as the ability to avoid cultural conflicts (n = 3). Teachers adhering to these two perspectives constitute the majority. Two teachers held isolated views on IC: one teacher believed that learning a foreign language equates to possessing IC, while another teacher equated IC with interdisciplinary skills.

The prevailing viewpoint among teachers is that IC involves understanding different cultures, respecting cultural differences, and, in some cases, employing critical thinking skills. Typical perspectives within this category include:

I think intercultural competence includes, for example, the ability to communicate effectively across different cultures, being able to express yourself verbally and understand each other’s meanings when interacting with others. Additionally, it involves having an awareness of and respecting differences. I believe it’s mainly about these two aspects. (T1)

I think intercultural competence is about understanding the differences between Eastern and Western cultures and whether you can accept and learn from the respective strengths of these cultures. For instance, when you encounter a cross-cultural situation, you need to adopt a critical mindset towards that situation. (T6)

When discussing IC, the most frequently used term is ‘understanding’ — understanding of other cultures and understanding cultural differences. According to Bloom's Cognitive Taxonomy model, ‘comprehension/understanding’ represents a lower-level cognitive ability. Remaining solely at the ‘understanding’ level is undoubtedly insufficient for fostering students' IC. Two teachers referred to higher-order skills, such as critical thinking; however, they expressed that they had not attempted to cultivate critical thinking skills through foreign language instruction. In summary, these teachers are more focused on the emotional or attitudinal aspects of IC, understanding it from specific dimensions, yet they tend to overlook IC's cognitive and behavioral dimensions.

The second type of teachers has a more straightforward understanding of IC. They believe that it refers to the ability to avoid conflicts:

When we attend English classes ourselves, or when we teach students in English classes, it is essentially a process of getting to know different cultures. Because we live in China, we’ve been influenced by our own culture for decades, and there are bound to be conflicts when we encounter a culture that we’ve only recently come to understand. Learning this language helps us avoid these conflicts, prevent misunderstandings, and enables us to have more friendly interactions between the two cultures. (T3)

From this teacher's statement, it can be inferred that he/she believes that learning the language of a foreign country can aid in avoiding misunderstandings and conflicts, thereby facilitating friendly communication. Indeed, IC encompasses the ability to recognize, prevent, and resolve potential cultural conflicts, manifesting as the capacity to fine-tune communication within a cultural context. However, it is important to emphasize that learning a foreign language does not automatically confer this ability. Equating language acquisition with conflict avoidance oversimplifies the essence of IC. Another teacher's perspective shares similarities with this group of teachers:

From a linguistic perspective, even the simple grammar of the language (English) is different from our native language. So, learning a new language requires a kind of intercultural competence — it involves understanding different ways of thinking. In essence, just learning a language itself involves developing intercultural competence. There are things implicit in the language itself that also require intercultural competence. Therefore, I believe that when students are learning (a foreign language), regardless of whether I explicitly explain it or not, they naturally develop this intercultural competence as they progress in language learning. (T5)

In contrast to the second category of teachers, this teacher did not mention the ability to avoid conflicts. However, they believe that language learning itself constitutes the cultivation of IC, a viewpoint that bears significant resemblance to the perspective of the preceding teachers. Considering these two categories of viewpoints, it becomes evident that the majority of primary school EFL teachers lack a comprehensive understanding of IC. They tend to oversimplify its essence or directly equate language learning or language proficiency with IC.

The final teacher's understanding of IC stands as an independent perspective. She perceives IC as the common ground between disciplines:

In my understanding, sometimes when I unintentionally observe their Chinese and math classes, it seems like there are overlaps between subjects. When they’re discussing certain topics, I notice that in Chinese and math, they’re actually talking about quite similar concepts. So, I think this idea of interculturality refers to the commonalities that exist between different subjects or disciplines. (T2)

This teacher's understanding of IC clearly derives from her comprehension of culture, where she views culture as ‘knowledge’ and ‘education’. Consequently, she interprets interculturality as being interdisciplinary. It is evident that a teacher's understanding of culture can significantly influence their interpretation of IC. Therefore, it is crucial to clarify concepts and establish a commonly accepted understanding from the outset.

Furthermore, it is noteworthy that when researchers asked teachers about their understanding of the concept of IC, similar to their attempts to define culture, most teachers displayed a strong sense of uncertainty and lacked confidence in describing their definitions. Up to six teachers made statements such as ‘I haven't encountered this concept before’, ‘I know very little about this’, and ‘This concept is not very commonly used for us’. Consequently, although as early as the 2011 version of the English Curriculum Standards for Compulsory Education [83] already emphasized the cultivation of students' IC, a significant prevalence of front-line English teachers not understanding or being unclear about IC persists.

4.3. Teachers’ intercultural teaching practices

From teachers' comprehension of culture outlined previously, the majority of educators find themselves situated within the framework of a structuralist cultural outlook, where culture is conceived as describable, rooted in ethnicity or nationality, and characterized by distinct boundaries in terms of lifestyles or products. Understanding teachers' cultural perspectives, it becomes evident that when researchers prompt teachers to describe intercultural teaching in their daily foreign language instruction, the majority of examples provided by teachers are oriented towards textbook-based, ‘background knowledge’ style presentation. Intercultural teaching mainly involves explicit connections with cultural topics such as festivals, foods, or folklore. Teachers deliver culture as factual knowledge, aligning their beliefs with their practices.

At this stage, I believe the key is to show kids some aspects of foreign culture as much as possible while they’re learning the language. This includes showing them things like customs, traditions, and local ways of life from different countries. The idea is to help them understand the differences between cultures, and this is what we refer to as cultural teaching within language instruction. (T10)

I mainly introduce cultural knowledge to students. For example, I explain the origin of April Fool’s Day and Halloween. I will tell them about the origins and let them realize that there is such a thing, and I will also talk about what foreigners do and what activities they have, just like this. (T2)

Since teachers' understanding of culture is often based on national or ethnic boundaries, the term ‘difference’ is frequently emphasized when discussing cultural teaching in language instruction:

Cultural teaching in language instruction … My understanding of it is … first, it’s about cultural difference. Because we have limited time, we focus on discussing significant differences between the two cultures. We emphasize those differences that stand out the most. (T5)

While cultural differences undoubtedly constitute a significant component of cultural teaching, researchers have noted a tendency among elementary EFL teachers to solely equate cultural teaching with the teaching of cultural differences. This inclination often leads to the neglect of commonalities across different cultures and the ‘shared space’ within cultures. Furthermore, this emphasis on difference revolves around teacher-centered presentations, where teachers inform students about the characteristics of the ‘Other’. There is an absence of attempts to enhance students' IC through methods such as reflection and inquiry. A typical cultural teaching process, as described by one participant, unfolds as follows:

In our actual teaching, we mainly rely on our textbooks. We don’t specifically focus on imparting culture as a separate teaching element. As I mentioned earlier, it’s more like when the textbook covers topics like festivals, greetings, weather, or numbers, we might briefly touch upon cultural aspects. For example, for the third grades, when we’re learning about names, we might mention the different positions between Western and Chinese names. And then, when we learn about regions, for example, in the United States, they have states, whereas in China, we have provinces. We basically just touch on it briefly as we go along. (T6)

From the discourse above, it's clear that casual and fragmented cultural teaching is quite prevalent. Educators of this kind typically recognize the importance of cultural teaching; however, they also acknowledge the absence of systematic cultural teaching in their daily instruction. The specific cultural information inserted into the classroom primarily aims to expand students' knowledge and enrich the classroom experience, with no apparent ulterior motives. This mode of cultural teaching is also referred to as the ‘By the way’ approach, as coined by Galloway [84].

Another intriguing finding is that, due to the prevailing structuralist cultural perspective among teachers, which emphasizes the notion of ‘one language, one culture, one nation’, the majority of educators regard IC as a higher-level ability compared to language proficiency. In other words, students are often expected to possess a certain level of language proficiency before they can engage in learning IC. When discussing practices of intercultural foreign language teaching, language proficiency as ‘basis’ is frequently mentioned:

In terms of intercultural competence … you should have basic language skills, and it will definitely be better if you have a certain (language) foundation. (T2)

I think you should have certain language competencies before you can learn about culture. If one does not have enough input in a language, he/she has no confidence to express the thoughts. Even if he has ideas, he cannot convey them well to others, then there are no exchanges or communications happening here. (T3)

It seems that primary school EFL teachers believe in a positive correlation between language ability and IC. They generally acknowledge the necessity and feasibility of cultivating pupils’ IC at the primary school level. However, they also emphasize the limitations of what they can achieve in primary school:

I think it is feasible. But I think that as students grow older, it would be better (to develop IC), for example in junior or in high school. While in primary school, it may not be so easy. (T7)

The provided quotation offers insights into why elementary school EFL teachers may lack familiarity with the concept of IC. They maintain that, given the current language proficiency levels of primary school students, it may not be an appropriate stage to cultivate their IC skills.

Although the majority of teachers adhere to the structuralist perspective, there are teachers who question the boundaries among cultures:

(IFLT) is not so easy to operate. I was very impressed by one class. The teacher talked about Chinese and Western food. At the end of the class, the teacher made a classification of Chinese and Western breakfast food. For example, bread, it belongs to the West … and hamburger also belong to the Western breakfast, and milk. The typical Chinese breakfast foods were noodles, dumplings, and Baozi … But when we were listening to the class, we had doubts and debates. The most controversial thing was bread and milk. We felt puzzled. In fact, you know that, in China, there are so many people who have bread and milk in the morning, right? Is it a difference or an integration? Actually, the boundary between Chinese and Western cultures is not so clear. (T6)

The teacher's question touches on the limitations of the structuralist cultural outlook in intercultural teaching. The cultural boundaries emphasized by the essentialist view of culture are historically and socially constructed. This was an artificial cognitive barrier, the effectiveness of which is based on a specific cognitive order, ultimately subjective [85]. As globalization and the influence of postmodernism continue to intensify, the flow of languages and cultures on a global scale, as well as the mixing or the ‘hybridity’ of languages and cultures [86,87], has become the norm, and many cultural phenomena can no longer be explained by the traditional essentialist cultural outlook. The teacher is keenly aware of the unreasonableness of classifying cultural differences in her cultural outlook. Although she is unable to propose a solution at that moment, her thinking on this problem can be regarded as the teacher's reflection and questioning on the essentialist cultural outlook.

5. Discussion

The aims of this study were to investigate teachers' understanding of culture and intercultural competence, and how their understanding of these concepts influences their intercultural teaching practices. Findings indicate that teachers generally define culture from a structuralist perspective, and they understand IC from one or several specific perspectives (from an attitudinal perspective, for instance). Teachers do not possess a comprehensive understanding of the essence and composition of IC, often demonstrating a propensity to oversimplify it, and, in some instances, equate it with the acquisition of foreign language skills. Teachers’ classroom intercultural instruction is scattered and casual, lacking systematic organization and planning. The primary content of cultural instruction is limited to the Big C of the target culture, which aligns with the essentialist cultural outlook held by the teachers.

Several findings are worth discussing. Firstly, the essentialist cultural outlook of teachers may serve as a significant constraint on the implementation of IFLT. Despite teachers universally acknowledging the importance of intercultural teaching in foreign language education [10,[12], [13], [14]], the cultivation of IC in actual pedagogical practice falls short of expectations [57,60]. Previous research indicates that potential reasons contributing to this situation include insufficient classroom time [10], inadequate IC training among teachers [88,89], ill preparation of teachers for IC instruction [54], misinterpretation of policies and concepts [9,40,55], and inadequate intercultural content in teaching materials [[90], [91], [92]]. However, the current study introduces another possible explanation: the essentialist cultural outlook held by teachers. Under the influence of an essentialist cultural outlook, cultural instruction centered around the 4Fs – food, fairs, folklore, and facts [78] – takes a predominant position. Research suggests that teachers' intercultural teaching is confined to a tourist perspective [93,94], restricted to the target culture only [38,92,95], and limited to the transmission of factual cultural knowledge [56,57]. Examining teachers' definitions of culture in this study reveals that such intercultural instructional practices align, to a certain extent, with the teachers' cultural outlook — that is, the way they comprehend culture. From this perspective, teachers’ understanding of culture will manifest intuitively in their pedagogical practices.

However, this study also identified inconsistencies between teachers' understandings and practices. While most teachers emphasized the attitudinal aspects of IC, such as understanding and respecting other cultures, when discussing their understanding of IC, in the context of discussing actual intercultural teaching practices, most teachers provided specific examples that focused on factual cultural knowledge, such as festivals and foods. Notably, none of the teachers mentioned any instructional practices aimed at cultivating the attitudinal dimension of IC. Prior research findings suggest that addressing intercultural attitudes is a prerequisite before imparting intercultural knowledge in instructional settings [1,32,96]. Yao's [97]study indicates that, compared to the cognitive and skill dimensions of IC, developing the attitudinal dimension, particularly fostering openness and curiosity, is more feasible at the elementary school level. However, despite teachers' beliefs in fostering an open and inclusive mindset, their teaching practices still primarily focus on imparting cultural knowledge.

Additionally, the current study suggests that teachers tend to emphasize cultural differences in the classroom while overlooking cultural commonalities, or the ‘shared space’ among cultures — a trend observed by Dervin [98]. This simplistic understanding of difference, often rooted in an essentialist cultural outlook based on national or ethnic divisions, neglects the increasingly complex cultural blending and hybridity of language and cultures [86,87]. Such an approach does not foster an intercultural perspective in students or enable them to become intercultural speakers. Therefore, supporting teachers in updating their language-cultural outlook and understanding the dynamic interaction and construction of language and culture become crucial for future teacher education and professional development.

Secondly, the research reveals a prevalent perception among teachers that IC is considered a more ‘advanced’ skill compared to language proficiency. However, there is currently a lack of consensus within the academic community regarding the relationship between language proficiency and IC. Some empirical studies have shown no correlation between the two [99] [100], while others have found some connection [101]. Nevertheless, primary school EFL teachers seem to believe in a positive correlation between language ability and IC. Hence, they believe that, constrained by the limited language proficiency and cognitive levels of elementary school students, elementary English teachers have a limited role in fostering students' IC. The researchers suggest that teachers' language and culture outlook could help explain their uncertainty to some extent. Specifically, their adherence to the structuralist perspective of culture asserts that each nation possesses a distinct language and culture, with language serving as a vehicle for conveying cultural aspects. From this standpoint, it is believed that one must attain a certain level of language proficiency as a prerequisite for comprehending other cultures. Given their essentialist standpoint, it is not surprising that these teachers perceive their role as relatively circumscribed within the context of elementary education.

However, teachers' intuitive perceptions regarding the cultivation of IC do not align with research conclusions in the academic community. Studies have affirmed the longitudinal nature of IC development [41,102] and the effectiveness of fostering students' IC at the elementary school level [97,103,104]. Notably, Zhang and Zhou conducted a meta-analysis of 31 empirical studies from 2000 to 2018 [50]. The results indicate a significant decrease in the effect size of interventions targeting students' IC from elementary school to university. Therefore, contrary to the perceptions of front-line elementary EFL teachers, fostering students’ IC during the elementary school phase proves to be more effective than in other educational stages.

But here we must point out that, in the Chinese context, scholars widely agree that in the initial stage of intercultural language learning, it is necessary to help students establish certain cultural frameworks, especially given the significant cultural differences with other cultures. However, as students progress to the advanced stage, they need to move beyond simple cultural types and develop a deeper understanding of cultural differences [105,106]. Therefore, rather than dismissing essentialism as a ‘simplistic’ foundation, it should be acknowledged as coexisting symbiotically with non-essentialist ideas and critically employed throughout the intercultural learning process [107]. The key point is not to completely abandon an essentialist cultural outlook, but for teachers to recognize its limitations in cultivating students' IC and consciously optimize its application in teaching.

Thirdly, teachers' daily instructional reflections serve as crucial opportunities for advancing the development of IFLT. Within interviews, teachers' questioning of cultural boundaries signals a shift from a structuralist cultural outlook towards a constructivist stance. This recognition of the limitations of an essentialist cultural perspective underscores the importance of reflective teaching. Reflective practice involves challenging assumptions, ideological illusions, damaging social and cultural biases, inequalities, and questioning personal behaviors that may silence or marginalize others' voices [108]. Byram et al. believe that language teachers need to cultivate an atmosphere in the classroom that encourages learners to take risks in their thinking and feeling, skills best developed through practice and reflection on experience [109]. Studies have proved that reflection guided by a contextual approach in teacher training is most effective in enhancing teachers’ IC [110]. The transition in FL objectives from emulating native speakers to fostering intercultural speakers requires FL teachers to engage in a systematic reflection on their teaching practices. Through self-analysis, teachers can better understand and adapt their instructional approaches [111,112]. Interviews with teachers already demonstrate their reflections on teaching practices. With proper guidance, these reflections can significantly enhance pedagogical practices and promote strategies for critical reflection and transformative change [113]. These processes are essential for developing critical cultural awareness and implementing IFLT.

6. Conclusion

The current study investigated the understanding of culture and intercultural competence among Chinese primary school EFL teachers and its implications for their teaching practices through interviews. Findings indicate that these teachers commonly adhere to an essentialist cultural outlook, demonstrating a somewhat simplistic understanding of IC. This is reflected in their instructional practices, which primarily involve providing background-knowledge-based factual cultural information, such as dietary habits and the origins of festivals. Due to a lack of dynamic and diverse comprehension of culture and IC, teachers generally perceive IC as a skill more advanced than language proficiency, leading them to believe that cultivating students’ IC at the elementary school stage yields limited effectiveness.

The current study has made the following contributions to the field of IFLT. First, it deepens our understanding of the connection between teachers' IFLT beliefs and their actual teaching practices. Teachers' understanding of culture and IC is directly reflected in their instructional approaches. Second, it sheds light on the factors influencing IFLT, identifying teachers’ essentialist cultural outlook as a potential constraint on the development of IFLT. Third, it provides insights for the cultivation of intercultural foreign language teachers. Reflective practices on daily teaching behaviors should be integral to teacher education, representing a significant opportunity to promote IFLT.

The study also identified a significant gap between teachers and IC researchers. Despite reaching consensus on many issues within the academic community, discrepancies persist among front-line teachers. For instance, scholars emphasize the importance and the feasibility of cultivating young learners’ IC, whereas teachers perceive their capacity to do so as limited. The research findings on IC by scholars have not been effectively translated into changes in teaching behavior.

The current study has its limitations. First, the research data solely derive from teacher interviews, rendering the data source somewhat singular. Existing studies indicate a divergence between teachers' professed beliefs and their actual instructional practices [10,73]. Therefore, future research could incorporate classroom observations of teachers. Data obtained through such observations would be more proximate to teachers' authentic teaching behaviors than interview-based data, offering a more accurate and objective depiction of the relationship between teachers' beliefs and practices. Second, as mentioned in the methodology section, due to our interview sample being drawn from teachers who responded to an online questionnaire, we did not have the option to select the participating teachers. This resulted in our inability to employ methods such as stopping criteria to determine data saturation. Future research could expand the number of interviews to ensure data integrity. Third, this study treats elementary school EFL teachers as a collective entity, without taking into account the influence of personal backgrounds, intercultural exposure, contextual factors, and other relevant considerations. Research indicates that teachers’ personality and life experiences [114], intercultural exposure [115], and intergroup interactions [116] can all influence their understanding of IC. Therefore, future research could consider segmenting the elementary school EFL teachers population, taking into account factors such as educational background, overseas experiences, and teacher education in the study. Through such research design, we can gain a better understanding of which teachers are more willing or more capable of engaging in IFLT, and how we can cultivate more educators with these attributes.

To conclude, this study indicates that teachers’ understanding of culture and IC intuitively manifests in their intercultural teaching practices. Therefore, supporting teachers in developing a more diverse, flexible, and dynamic language-cultural outlook is crucial in achieving effective IFLT. The transition from conventional proficiency-focused language instruction to the more demanding realm of IFLT necessitates collaborative endeavors among researchers, foreign language educators, and educational authorities. It is expected that this study will offer valuable insights for other nations where English is taught as a foreign language.

Ethical statements

This study was reviewed and approved by the Ethics Committee of University of Wales Trinity Saint David, with the approval number EC744. The questionnaire was administrated online with clear descriptions about the purpose of data collection. All respondents were recruited on a volunteer basis and well-understood that the use of their responses is for research purpose only. All participants was provided with the information sheet, and all participants provided informed consent to participate in the study before data collection. Moreover, all participants’ details are fully anonymize.

Data availability statement

Data associated with this study has not been deposited into any publicly available repositories. The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

CRediT authorship contribution statement

Huang Wang: Writing – review & editing, Writing – original draft, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. Tianyuan Xu: Validation, Resources, Conceptualization. Zheng Zhong: Writing – review & editing, Resources, Project administration.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

The following is the Supplementary data to this article: