The Educational Dimension as an Emergent Topic in the Management of Heritage: Mapping Scientiﬁc Production, 1991–2022

: Heritage is increasingly present in educational discourses, yet research on heritage education still lacks literature overviews that identify trends in its scientiﬁc production worldwide in order to get to know the discipline’s advances, evolution, and impact. This article collected a bibliographic review of n = 223 documents indexed in Scopus and the Web of Science between 1991 and 2022. The analysis was carried out in two phases. During the ﬁrst phase, distance-based maps were constructed using the VOSviewer 1.6.16 software. During the second phase, a systematic review was carried out based on methodological classiﬁcation and a content analysis. The study identiﬁed thematic networks of (C1) heritage education in formal education, (C2) heritage education, cultural heritage, and educational innovation, (C3) archaeological heritage education, (C4) heritage education, case studies, and historical awareness, and (C5) heritage education, and classiﬁed research genealogies and methodologies, which, in turn, led to the deﬁnition of two emerging genealogies: teacher training and instrumental, which were added to re-conceptualizing, contextual didactic, and evaluative, and ultimately identiﬁed a predominantly qualitative methodology. A classiﬁcation of the methodologies, methods, and techniques of heritage education research was also made. This study constitutes a clear and pioneering contribution to our understanding of this discipline.


Introduction
Heritage has an ever-growing presence in educational discourses as a result of its cultural, sociohistorical, and natural value and its contribution to the acquisition of key abilities like social and civic competence or competence in cultural awareness and expression [1][2][3][4].At the same time, heritage education has become an indispensable tool in empowering society to achieve self-sustaining heritage management [5][6][7].
From the epistemological point of view, the origins of this notion have been traced to Ibero-America, where we can find several publications like Horta et al. [8].According to Teixeira [9], it was in Brazil in 1980 that the designation educação patrimonial was introduced by these authors in conceptual and practical terms, that, in turn, were inspired by Britain's pedagogical work on what was already termed heritage education during the previous decade, which coincided with the impetus provided by the United Nations Educational, Scientific, and Cultural Organization.Briggs [10], one of the pioneers in promoting the term, claims that 1975 meant the starting point for heritage education, since it was in that year when a deliberately comprehensive project was launched, including all settings, disciplines, and educational levels.The project impacted on all British schools, and, according to Hamer [11], 'heritage education was here closely linked to furthering knowledge, understanding and appreciation of the historic built environment and to using it as a resource to support the teaching of a range of subjects' (p.159).The search for a common nomenclature consolidated the original British term 'heritage education', which was also used in the United States, as well as its counterparts in Brazil and Portugal (educação patrimonial), Spain and Hispanic America (educación patrimonial), and France (éducation au patrimoine).
The discipline's international trajectory is relatively laconic, since heritage-related education did not emerge as such until 1972 with the creation of the Convention concerning the Protection of the World Cultural and Natural Heritage from UNESCO [12].It was in this convention where educational programs were enunciated as a means of stimulating respect and appreciation for cultural heritage and where goals like awakening the interest of society and increasing respect for cultural and natural heritage were explicitly formulated.Another institution involved in heritage education issues is the Council of Europe [13], in whose regard a special mention must be made of Recommendation No. R (98)5 concerning heritage education, which meant the beginning of a process leading to the construction of a formalized framework for this topic.The recommendation defined heritage education as 'a teaching approach based on cultural heritage, incorporating active educational methods, cross-curricular approaches, a partnership between the fields of education and culture and employing the widest variety of modes of communication and expression' (p.31), and encouraged member states to adopt appropriate legislative, regulatory, administrative, financial, and other measures to initiate and develop heritage education programs and to promote heritage awareness among young people [14].Later on, in 2017, the Council issued Recommendation CM/Rec (2017) 1 to member States on the European Cultural Heritage Strategy for the 21st century, the aim of which was to educate and raise the awareness of citizens concerning the management of their cultural heritage [15].This was the beginning of a huge epistemological task involving the analysis and evaluation of educational practices.
Heritage Education is a latent discipline from a normative point of view, which demands an increasing curricular recognition, since its presence in both education laws and regulations for wealth management has increased over time [16,17].It is also a discipline that has had an important development in the past two decades, which justifies the need for an analysis of the scientific production in this area.

The Present Study
Beginning in 2005, a steady increase in scientific turnout has taken place, especially in countries like Brazil [9,18,19], the United Kingdom [11,20], China [21,22], Italy [23,24], Israel [25], or the Netherlands, where research work consolidating this discipline began to be published.For this reason, it is important to analyze the whole of this data volume in order to define the state of the question and establish the point in time when this emergence took place, as well as the sources and provenance by country of the major portion of this output.On a global scale, the ecosystems of scientific production have gradually consolidated their impact in order to match the progress of knowledge transfer and the accelerated pace of research.The kind of analysis furthered by this paper is indeed a must in any area of research, so as to gain clear, unequivocal insights into the progress of any given discipline.In this sense, despite the existence of bibliometric studies on research outputs in bordering fields, like, for example, research on education and heritage research in museums [26], social science teaching [27], or on museum education published in journals indexed in the Web of Science [28], so far, we lack specific analyses on heritage education that may enable us to identify trends and publication patterns.In this context, the specific goals of this study are: (1) to learn about the evolution of this output; (2) to identify thematic networks on a worldwide scale; and (3) to classify research genealogies and methodologies and spot emerging issues that concern the scientific community.

Materials and Methods
In order to carry out this study, we drew upon a research article on history education in the WoS database [27], which, in turn, resorts to a bibliographic network analysis and science mapping [29].In this way, we were able to represent the structures generated as a result of heritage education research on the basis of the proposed goals.

Search Criteria
In scientific quality evaluation processes, the impact factor constitutes an inescapable reference, and this is why our bibliometric analysis addresses the research production included in the major databases Scopus and the Web of Science Core Collection.In order to extract the sample, 7 selection criteria were set up following our research goals: (1) Search database: Web of Science Core Collection and SCOPUS.(2) Subject Areas: All.(3) Document Domain: Article.(4) Years of publication: Since 1991, when the first reference to the term appeared in Briggs [10], to the present time: a time span that frames the development of the discipline itself.(5) Search Field: Title, abstract, author's keywords and more.(6) Thematic Descriptor: 'Heritage Education' has indeed consolidated itself as a global, unified term born out of this discipline, as defined by the UNESCO's specialized agency for education, science, and culture [30], in reference to Art. 27 [12] and the Council of Europe [14].Additionally, no search strings or other semantic terms like 'heritage teaching' or 'heritage literacy' were used, since these are comprised within the phrase heritage education.( 7) The term's lemmatization was disabled.This search modality made it possible to delimit the exact term and prevented us from including its inflected forms, while browsing exclusively for records that contained the exact term and preventing its separation.

Data Extraction and Analysis
The study sample comprised the bibliometric data extracted from both databases in February 2022 and amounted to a total of 325 documents.This sample was refined through a systematic individual review of the publications in order to eliminate duplicated items or items whose main topic did not belong to the specific area of knowledge.On the whole, 223 documents were analyzed, of which 122 were published in journals indexed in the Web of Science, while 176 came from journals indexed in SCOPUS and 75 were drawn from journals indexed in both databases (see Figure 1).Regarding each one of the databases mined, 120 documents (53.81%) originated journals indexed in the ESCI database, 49 came from SCOPUS (21.97%), 27 from SSC (12.11%), 20 were published in journals indexed in A and HCI (8.97%), 4 were drawn fro the SCIE (Science Citation Index Expanded) (1.79%), and the remaining 3 (1.35%)we extracted from journals indexed in several databases.Table 1 shows the basic informatio Regarding each one of the databases mined, 120 documents (53.81%) originated in journals indexed in the ESCI database, 49 came from SCOPUS (21.97%), 27 from SSCI (12.11%), 20 were published in journals indexed in A and HCI (8.97%), 4 were drawn from the SCIE (Science Citation Index Expanded) (1.79%), and the remaining 3 (1.35%)were extracted from journals indexed in several databases.Table 1 shows the basic information concerning the analyzed dataset.The analysis was conducted in two phases.During the first one, distance-based maps were constructed using VOSviewer [31], which is a valuable bibliometric analysis tool that can effectively visualize and analyze bibliographic networks, including co-authorship, co-citation, and co-occurrence networks.It allows gaining a comprehensive understanding of the network structure and relationships within a specific research field, which can aid in identifying key research areas and emerging trends.Also, it allows for the identification of clusters and the mapping of bibliometric data, where the distance between every pair of items mirrors the strength of their association.It can help to identify thematic clusters, research hotspots, and the interrelationships between different research topics.During the second phase, we described the evolution and topics of publications between 1991 and 2022, through a systematic review based on the methodological classification and a content analysis.

Results
The results that we present next foreground the evolution of the conceptual and intellectual structure of this field of study.They represent the evolution of its scientific output and the connections among the several topics addressed by the articles.

Thematic Networks and Lines of Research
The first analysis we performed identified five thematic clusters (see Figure 2).From the total number of 658 key words provided by the authors, 49 were selected as having a rate of occurrence higher than three.Cluster 1, in red color, brings together 17 items and has as its central node the key word 'Heritage Education'.This cluster addresses heritage education in close connection to teaching in formal education settings, as is reflected in items 'curriculum', 'primary education', 'secondary education', 'program evaluation', and 'textbooks' [16,17,32,33].Also outstanding is the education and training of teachers, which includes the items 'teacher education', 'learning', and 'teacher training' [34][35][36][37].Some of the main items that come together in this cluster are 'identity', 'museums', 'identization processes', 'citizenship education', and 'assessment' [38][39][40].Cluster 2, in green color, brings together 12 items.This cluster features a line of heritage education related to intangible cultural heritage and its innovative teaching, which is reflected in items like 'ICTs', 'innovation', and 'intangible cultural heritage' [41][42][43].Other items found in this node are 'citizenship', 'history and history education', and 'cultural heritage education', which are amply represented in studies like [36,44,45], all concerning the teaching of history through heritage education.In turn, these items are related to others like 'museum', 'education', 'teachers', and 'teaching', a prominent example being the study by Álvarez et al. [28], who mined the Web of Science for the subject of heritage education in museums.
The blue-colored cluster 3 encompasses 10 items that revolve around the specific topic of education in archaeological heritage.Within this cluster, the items 'archaeology', 'awareness', and 'public archaeology' stand out [1,[46][47][48].This node also includes items like 'evaluation', 'inclusion', 'culture', 'education', and 'research', which have attracted numerous research papers about the need to evaluate educational practices [49], and also others that have addressed the inclusion of differently abled persons [50,51].
Cluster 4, in yellow, includes the items 'historical awareness', 'case study', 'formal education', 'identity', 'memory', and 'heritage'.Within this cluster, a special mention must be made of the key word 'case study', which exhibits a high enough level of co-occurrence.This research method is frequently used in research work on identity, memory, and historical awareness [52,53].
The last cluster, in purple color, features four items: 'augmented reality', 'mobile learning', 'heritage teaching', and 'web 2.0', which, in turn, mirror a line of heritage Cluster 2, in green color, brings together 12 items.This cluster features a line of heritage education related to intangible cultural heritage and its innovative teaching, which is reflected in items like 'ICTs', 'innovation', and 'intangible cultural heritage' [41][42][43].Other items found in this node are 'citizenship', 'history and history education', and 'cultural heritage education', which are amply represented in studies like [36,44,45], all concerning the teaching of history through heritage education.In turn, these items are related to others like 'museum', 'education', 'teachers', and 'teaching', a prominent example being the study by Álvarez et al. [28], who mined the Web of Science for the subject of heritage education in museums.
The blue-colored cluster 3 encompasses 10 items that revolve around the specific topic of education in archaeological heritage.Within this cluster, the items 'archaeology', 'awareness', and 'public archaeology' stand out [1,[46][47][48].This node also includes items like 'evaluation', 'inclusion', 'culture', 'education', and 'research', which have attracted numerous research papers about the need to evaluate educational practices [49], and also others that have addressed the inclusion of differently abled persons [50,51].
Cluster 4, in yellow, includes the items 'historical awareness', 'case study', 'formal education', 'identity', 'memory', and 'heritage'.Within this cluster, a special mention must be made of the key word 'case study', which exhibits a high enough level of cooccurrence.This research method is frequently used in research work on identity, memory, and historical awareness [52,53].
The last cluster, in purple color, features four items: 'augmented reality', 'mobile learning', 'heritage teaching', and 'web 2.0', which, in turn, mirror a line of heritage education research closely linked to new technologies, which has a larger presence in nonformal educational settings [22,25,54].Additionally, the use of augmented reality seems to exert a great influence on archaeological heritage education [2,55].

Thematic and Methodological Classification and Analysis of the Sample's Evolution
In order to define a classification consistent with previous studies, we chose as a starting point the triad of research genealogies described by Fontal and Ibáñez-Etxeberria [56] (2017): respectively, the re-conceptualizing, didactic-contextual, and evaluative genealogies.In turn, each of these strands has been further subdivided into several subfields in order to achieve a greater accuracy in the definition of the several lines of research resulting from the systematic review of published articles.Finally, two additional genealogies of researchboth in emerging areas-were defined, so as to include new topics, thus making a new contribution to the understanding of current lines of inquiry (see Table 2).These emerging genealogies, respectively, correspond to teacher training and instrumental research aimed, among other things, at a more veracious measurement of the quality and adequacy of the implementation of heritage-related actions.If we now undertake a chronological examination of the origin of these topics, the first article in our sample dealt with heritage teaching resources [57], one of the least prolific lines of research in the sample (4.03%), which did not reappear until 2014 [58].In 2005, there appeared the first theoretical article on the concept of heritage education [59], one of the lines of research with the highest rate of occurrence (20.63%), which, nevertheless, and despite its four occurrences in 2011 and two occurrences in 2013, failed to sustain a steady output until 2015.Within this genealogy, there is a clear evolution of the core topics, which began by addressing the term itself and its development [59] gradually to narrow the focus down on recounting several approaches or on the integration of ICTs, always on the basis of theoretical reviews that were more narrative than systematic.
The first two articles on program evaluation, one of the most outstanding lines accounting for 15.7% of scientific production, can be traced back to 2006 [9,60].In 2008, there was the publication of the first study to analyze, by the means of a questionnaire, the conception of heritage entertained by primary and secondary education teachers in several areas of knowledge.This is not a particularly prolific line of research (9.87%), even though in 2017, there was indeed a rise.In 2009, there appeared the first publication on educational museography [21], a line of research that accounts for 8.97% of the scientific turnout.This is one of the most outstanding lines of inquiry, quite unlike the study of heritage education proposals in formal education: a topic whose first published contribution dates back to 2010 [61] and whose scientific yield represents only 4.03% of the sample.
The first article tracing the presence of heritage in secondary school textbooks was published in 2011 [62]; from then on, systematic reviews began to be published on the legislative, curricular, and textbook treatment of heritage issues, which account for 8.52% of the sample.Indeed, this year stands out as especially productive across the broad range of topics, yet with a special emphasis on theoretical concerns [56,63] and program evaluation [56].
In 2012, there appeared a new line of research aimed at learning outcomes [64].This is not a highly specialized avenue of study and it barely represents 4.03% of the published output.The year 2013 was the year of the publication of the first article to address heritage education in localized non-formal settings-archaeological sites, mines, wine cellars, and cities, etc.- [52].This has been a particularly steady line of research over the last few years and accounts for 8.52% of scientific production.Both of these publications and the set of studies on educational museography (8.97%) represent proposals for heritage education in non-formal settings and take up 17.49% of the scholarly output, in contrast with the 4.03% covered by proposals implemented in formal settings.Again, within this segment dealing with localized settings, we discerned a predominance of narrative articles published in countries like Brazil (and generally in Latin America), where memory, multiculturality, or identity constituted central issues for the safeguarding of heritage [65,66].In 2014, there appeared an emerging line, which, in turn, would shape one of the established new genealogies: teacher education.From this moment onwards, this avenue of research has not ceased growing, and today, it represents 8.37% of the total published output.The training of educators and implementation of continuing education constitute much needed lines of inquiry that were already announced at the Committee of Ministers [14] (1998), even though they have not been addressed in a sustained fashion until the present time.These contributions predominantly focus on the college-level training provided by a degree in Primary Education [35,37,67].Finally, in 2016, there started a more empirical line of instrumental research dedicated to designing and calibrating tools that may enable scholars to gain more accurate, unbiased insights into this subject [68].
As far as thematic topicality is concerned, studies have gradually engaged the use of new technologies that have developed from the use of tablets, apps, and virtual visits [2,6,58,69].This has led to the current interest in the implementation of virtual reality [70][71][72], stereoscopic photography [73], or 360 • photography [74].One of the most pioneering and prolific lines of research is program evaluation, with a total of 35 articles, and so are theoretical reviews, with 46 publications.Both subfields, respectively, lead the reconceptualizing (39.02%) and evaluative genealogies (23.76%).Program evaluation, which initially hinged on the implementation of case studies [47,60,75], has continued to evolve until the present time by developing new methodologies that combine the collection of both quantitative and qualitative data [76,77].Moreover, in early studies, evaluation work was targeted at the design of educational programs, but from 2017 until the present day, the evaluation of apps has increased its presence in parallel with the evolution of educational resources and teaching innovation [42,72,[78][79][80].The (re-)conceptualizing genealogy is the one that yields the largest scientific production (39.02%), followed by the didactic-contextual genealogy of research (25.55%) and, ranking third, the genealogy of evaluative research (23.76%).Behind them are the more incipient genealogies that deal with teacher education (8.97%) and instrumental research (2.7%).

Methodological Classification and Evolution
On the other hand, in order to learn about the main methodologies, methods, and techniques used in gathering and processing information in the context of heritage education research, while also tracing their evolution over time, we produced a rigorous classification following the taxonomies by Ato et al. [81] and Bisquerra [82], which are synthetically presented in Table 3.The first three methodologies were drawn from empirical research conducted in psychology [81], once it was adapted for the purposes of educational research.Among them, a mention must be made of the theoretical methodology, one of the most frequently employed and accounting for 30.90% of the sample.This comprises three review methods, respectively, termed narrative (19.73%), systematic (11.21%), and systematic-quantitative (as of yet yielding no publications).As can be observed, the majority of studies resort to narrative reviews of the literature involving subjective, non-systematic procedures [13,63] or else systematic ones that engage in quantitative data analyses, implying categorization and content analyses by the means of software packages like N-Vivo or Atlas Ti, [7,83].
The instrumental methodology is one of the least prominent, with a representation of only 1.79%; it does not always follow rigorous psychometric procedures like the ones employed in the article by Fontal et al. [49], but it does involve the use of evaluation instruments that have undergone a process of validation.
The so-called methodological-didactic is the third most represented methodology, reaching 17.94% of publications.Within this segment, 16.60% of articles describe educational programs with a focus on their didactic component, with there being no or only a very superficial evaluation [25,53], while a mere 1.34% define new program evaluation methods with a focus on the methodological aspect.
The empirical methodology does not exhibit a particularly high profile, yet, if we put together the four methods it encompasses, as described by Ato et al. [81] (2013), it accounts for 15.25% of the sample.Among them, there stands out the non-experimental method based on systematic observational processes and on the study and analysis supported by surveys and questionnaires, which represents 9.42% [32,35,36].Next, follow the quasiexperimental studies, 3.59% of the sample, mostly conducted on the basis of pretest-posttest procedures and control groups [69].Finally, experimental methods, which account for 2.24% of the sample, are mainly based on data quantification and variable manipulation [6,64,77].The fourth method included in the empirical methodology subgroup yielded no results.
The humanistic-interpretive methodology provides yet another robust research strand in heritage education, which represents 19.73% of the total sample with a total of 44 published articles.Within this methodology, the most outstanding (and remarkably incipient) one is case studies, which takes up 15.7% of the total sample.The first publication to implement this appeared in 2006 [60], while it reached its high point in 2017 and has managed to sustain its momentum until the present time [2,53,84].The studies that deploy an ethnographic method represent 3.59% of the sample [85].
On the other hand, the sociocritical methodology, which relies on a reflective critique aimed at explaining, understanding, and transforming social realities, represents 13.46% of the sample.Within this approach, Bisquerra [82] further distinguished between two methods: action research, which delivers 2.7% of the total number of publications [86], and evaluative research, which is far more frequent in sociocritical studies and accounts for 10.76% of the sample [9,67,87].Finally, the arts-based methodology was added to the list [88,89].
With regard to frequencies in terms of research paradigm, there is a strong trend for qualitative studies (n = 173) versus quantitative (n = 26) or mixed ones (n = 22).This qualitative trend matches the nature of the educational subject itself, where each case is different and individualized, while their predominant goals are to understand, interpret, and transform (there being few generalizable examples), in contrast with other studies that seek to explain, predict, or verify phenomena.Finally, most studies resort to techniques for the observation of heritage-related educational actions [43], collect data by the means of surveys or questionnaires, or perform an analysis of content by using software packages for the analysis of qualitative data like Nudist or N-Vivo [7,90].Not all studies clearly identify the method or techniques employed, while, in several cases, despite their claim to use case studies and their explicit reference to models like Stake [91] or Simons [92], they can hardly be said to conduct this in a comprehensive and detailed way.

Conclusions
In the last few pages of this literature review, we intend to contribute a comprehensive reading of the data in order to meet this study's central aim, i.e., to identify the discipline's research trends and analyze the sequential evolution and interconnections of publications on heritage education.By the means of keyword clustering, we were able to identify five subject-based clusters: (C1) heritage education in formal education, (C2) heritage education, cultural heritage, and educational innovation, (C3) archaeological heritage education, (C4) heritage education, case studies, and historical awareness, and (C5) heritage education, new technologies, and non-formal education.Similarly, by focusing on the studies' main subject matter and their transversal goals, we defined five genealogies of research on the basis of the genealogies proposed by Fontal and Ibáñez-Etxeberria [57] (2017): (G1) re-conceptualizing, (G2) didactic-contextual, (G3) evaluative, (G4) teacher education, and (G5) instrumental.In turn, these genealogies were subdivided into thematic subfields.
The last two represent emerging areas: the first one started in 2011 in response to the needed lines of action already made public by the Committee of Ministers (1998) [14], concerning the initial and continuing training of teachers.It was also a logical consequence of the results produced by systematic reviews of the legislative, curricular, and textbook treatment considering the matter of heritage, which regularly insisted on the fact that the only way of securing the presence of heritage education in classrooms is by concentrating on the initial training of teachers themselves [93,94].The inception of the second genealogy, on the other hand, dates back to 2016.This constitutes a more empirical line of instrumental research aimed at designing and calibrating instruments that may enable researchers to gain more accurate and unbiased insights into the study matter [49], while also bridging gaps in the validation of the discipline's methods.
All of the above categorization makes it possible not to only organize the research subject, but also to understand how it is structured and how it evolves in regard to the discipline's research interests and landmarks, as well as educational and technological advances, where results are obtained in line with related studies [26].Ultimately, moreover, it underpins the realization that heritage education is a discipline with a corpus of its own, characterized by hinging on a constantly evolving concept that supports significant teaching across several areas of knowledge.Such a diversity is matched by the interdisciplinarity and transversal nature of a subject matter that cuts across specific areas like the Didactics of the Social Sciences [90], Cultural Studies or the Didactics of History [36,74], and Arts Education [16,37,38].
Methodology wise, it is worth noting that we are in front of a predominantly qualitative discipline, since, no matter how some processes may share a common set of methods, the main actors, places, and objects that make it up are always unique and therefore hardly generalizable; even so, it is important to call for quantitative studies as well that may contribute relevant data.The data themselves encourage a continuing theoretical search resulting from systematic reviews and feeding an explanatory, observational trend that relies on a humanistic-interpretive approach implemented on a high number of case studies.This, together with the current sociocritical inquiries based on the evaluation of practices, can pave the way for an evaluative culture geared towards the improvement of the quality of education.
The main research needs and continuity lines point to reaching greater depths in the validation of instruments and systems, the design and exploration of new methodologies, the ongoing inquiry into new educational contexts and virtual resources, and the examination of educational and teaching competences, with a special focus on digital skills, as suggested by Álvarez et al. [28].Last but not least, another horizon of research worth referring to constitutes studies based on sustainability and the involvement of heritage education in the sustainable development goals.Heritage is indeed a fundamental pillar in understanding the past and present, but also in mapping out the future, and, as such, heritage-based education is critical: a guarantee of citizenship based on tolerance, respect, civic values, knowledge, and democracy, and also a safeguard for the preservation of culture, in turn, the foundation of humanity and the values of different communities [95].Therefore, it is a crucial issue on a global scale.Such a view of heritage education as a broad and comprehensive concept that acknowledges the need for persons and human values to stand at the heart of a wider and interdisciplinary conception of cultural heritage has already been espoused since 2005 by the Framework Convention on the Value of Cultural Heritage for Society of the Council of Europe [96], even though the goals set up at the time have not yet fully been attained.
Nor can we ignore the current worldwide state of affairs concerning heritage education, which has keenly sought to reach out to the public opinion through social media and virtual platforms as we experience a historic turning point where we cannot just ignore the fundamental issues that relate to education in the post-pandemic era.Already, work is being performed considering new lines of research where heritage education is problematized, re-signified, contextualized, or related to conflicting heritages.Following a number of recent events the destruction of Palmira (2015), Hagia Sofia's reconversion in Istanbul, or the removal of statues in the wake of the 'Black Lives Matter' protests in several places worldwide, we have been made aware that social ignorance, decontextualization, a lack of awareness, and desensitization towards heritage encourages society to destroy heritage assets as a means of social protest.Such events simply foreground the much needed and urgent presence, visibilization, and implementation of heritage education in classrooms and non-formal educational settings, so as to reach out to a responsible, critical, yet respectful citizenship.
To conclude, in view of the absence of thorough literature reviews on the subject of heritage education, the present study constitutes a clear and pioneering contribution to our understanding of this discipline.For future lines, this research can be complemented with other bibliometric analysis tools, such as the Bibliometrix software (https://www.bibliometrix.org/home/)[97].This international review provides additional rigor to the matter at hand by contributing an international-level systemic state of the question, which researchers can use as a point of departure and the source of structured, current bibliographical information, in as much as every piece of research in this field inevitably rests on the discipline's origins and evolution.

Figure 2 .
Figure 2. Network of co-occurrences resulting from the analysis of key words in network visualization.

Figure 2 .
Figure 2. Network of co-occurrences resulting from the analysis of key words in network visualization.

Table 1 .
Summary of basic results of the whole dataset.

Table 3 .
Classification of heritage education research methodologies, methods, and techniques.