Introduction

Consumer studies have concentrated their research on the adult population (^{Baumgartner, 2010}; ^{Fetscherin et al., 2019}; ^{Jia et al., 2018}; ^{Pinzón & Pérez-Acosta, 2020}), due to their immediate relationship with the choice of products and the commercial transaction. However, there is a growing interest from various academic and business organizations to deepen their understanding of psychological processes and behavior patterns of the child population in terms of product consumption. Research on brand loyalty and children's conspicuous consumption dates back to the 1950s and it was not until the mid-1970s that this field of study gained visibility in the marketing community. Currently, the study of the child population behavior is considered central for the development of marketing strategies, communication and social programs (^{Barriage et al., 2017}; ^{John, 1999}).

On the other hand, social marketing aimed at the child population shows evidence of positive impact on this population, favoring practices related to physical exercise, so it can contribute to the development of healthy habits (^{Bagramian et al., 2019}; ^{Deshpande et al., 2015}: ^{Schuster et al., 2015}), not only based on communication strategies, but also from the families approach, in whose context various decision patterns and choice of products and services are modeled and reinforced (^{Aleti et al., 2015}). This vision of marketing is socially fundamental, because it regulates and promotes social ties, healthy behavior patterns, responsible and empathic actions with other people and with the environment. It serves as a regulating factor of advertising content and marketing actions that seek to increase consumption by influencing their behavior in stores or commercial surfaces (^{Martin-Biggers et al, 2013}), on television, (^{Calvert, 2008}: ^{Effertz & Wilcke. 2012}). in online environments (where they face various risks) (^{Kennedy et al., 2019}) and in video game environments (Sáleme et al., 2020).

Children assume a user role, benefiting from the products that third parties purchase for them: however, as consumers, children can play roles of users and influencers, depending on the preference for brands and the level or degree of dominance over their parents, directing the choice of products at the time of purchase. Now, in contexts where this population has economic resources and the functional atmosphere or environment facilitates the acquisition of products, children assume the roles of buyers and users, carrying out a process of selection and commercial transaction to stock up on products to supply themselves with products that meet the needs they consider important, based on their cognitive development and the particular characteristics associated with their age (^{Ortegón Cortázar et al., 2015}; ^{Rohde & Mau. 2021}).

In general, it is possible to affirm that there is a relationship between child development and the interaction they have with brands (^{Ortegón Cortázar et al., 2015}: ^{Royo Vela & Ortegon-Cortázar, 2019}). Understanding these interactions is essential for the advertising communication that brands create, offering a fundamental heritage hi understanding the phenomenon of brand learning (^{Sandoval-Escobar et al., 2018}). Due to the great importance of child consumption, there are different lines of work in addressing this topic in consumer psychology. Traditionally, these investigations are oriented to the impact of the family on consumption habits (^{Geuens et al., 2003}), nutrition (^{Collins et al., 2014}: ^{Koplin et al., 2019}; ^{Pries et al., 2019}), the consumption of alcoholic beverages (^{Seilhamer et al., 1993}), drugs and tobacco (^{Nunez-Smith et al., 2010}), with a great diversity of findings, models, and results. However, no studies have been identified that have described the areas of inquiry, the groups that carry out these works, the corresponding disciplines and the most important findings that account for the psychological processes involved hi child consumption and their relationships with the consumption of brands (^{Bucher et al., 2016}).

Thus, the present systematic bibliometric study aimed to identify and analyze the lines and areas of research hi relation to children's consumption, to establish which are the most important publications, authors and trends in this field of research within the period from 1974 to 2019. For this purpose, only scientometric indicators resulting from the search of articles hi a database were used, with terms associated with marketing and child consumer psychology, from a psychological, economic and social perspective.

Method

Results

The result of publications shows peaks of a high number of citations of documents associated with issues of child consumption, for the years 1981. 1992 and 1999. The scientific production in this area of knowledge has a sustained behavior with a growth rate of 11.38 (Figure 1). The average number of articles per author is 0.529. the average co-authorship per article is 2.28 and the average of authors per article is 2.37.

The five most productive countries are the USA (320 articles), the United Kingdom (61 articles), Australia (54 articles), Belgium (27 articles), Canada (25 articles), and the Netherlands (25). The average number of citations by country varies the order in the first five nations: USA (10415), United Kingdom (1940), Australia (956), Canada (676), Hong Kong (596). On the other hand, the country with the largest national and international production hi scientific research related to children's consumers is the United States. The five authors with the highest production of research articles are Chan, K; Buijzen, M; Valkenburg, PM; Bakir, A; Chaudhary, M (Figure 2).

Regarding the most relevant journals by the number of publications in marketing research directed at children's consumers, these were: Young Consumers (35 articles), Journal of Consumer Marketing (12 articles), International Journal of Retail and Distribution Management (9 articles), International Journal of Consumer Studies (8 articles), Journal of Business Research (8 articles).

The five most used keywords (Table 2) are: children (60 articles), children age groups (28 articles), consumer behavior (45 articles), education (25 articles), gender (24 articles). The Bibliometrix analysis highlights the keywords hi two ways : the main one being the general list of the frequency per year of the keywords most used in SCOPUS (keyword expansion) (ID) and the keywords used by each author and associated with the general listing (keywords associated with author) (DE) (^{Aria & Cuccurullo, 2017}). Under the search strategy used, the results are presented hi Table 1.

Regarding the most cited articles. Table 2 indicates the number of citations (TC) and the average number of citations per year (TC per year). These articles with the highest number of citations are of a traditional nature, having as object of study consumption practices in general without an emphasis on the child population (^{Aria & Cuccurullo, 2017}).

Bibliometric results in terms of authors have two categories depending on the indicator applied: the number of articles published in the period and their level of citations within other articles included in the search strategy, which determine productivity. On the other hand, there is a relationship that indicates the fraction of articles written by various authors hi which an academic appears as the first author. This is called the dominance factor (DF) (^{Kumar & Kumar, 2008}) and expresses the degree of mastery of an author in his research group (Table. 3).

The authors' bibliometric parameters are expressed in indices. Table 4 shows the result by H index (^{Feng et al., 2015}). G index (^{Egghe, 2006}) and M index (^{Choudhri et al., 2015}) for the first ten authors in the analysis of the 1375 documents included in this study.

On the other hand, documents can be grouped by bibliographic coupling. In this way. the authors create work networks relating their articles by having references shared hi the bibliography. Hie results show three groups of authors (Figure. 3). In this case, from right to left of the image, there are two groups marked hi blue lines, the first of which is headed by Yablonsky C, followed by Lindrdge A, Ustundagli E, Ciercierski C and McKinlei J. The second group includes Aljallad C, Hernandez K, Yorkin M and Weinberger MF. A common author between these two networks is Martin-Biggers J; her articles are focused on infant feeding, family practices, promotions, and the prevention of obesity. In turn, the works of Martin-Biggers J. are associated with those developed by Byrd-Bredbenner C, who since 2002 investigates eating in a close relationship with children, then behavior and the various factors that impact consumption habits of food, such as advertising, communication, health promotion and social marketing. Professor Carol Byrd-Bredbenner is a seminal author on research related to infant food consumption (Byrd-Bredbenner et al., 2017).

On the other hand, the dynamics in the authors' investigations can be observed from the evolution of their investigations in the number of articles published and the citations for each document, as well as the networks that are woven between the authors over time (Figure 4). As a result of this analysis. Chan K. is the most productive author, with nearly 160 articles. He directs his investigations to the consumption habits of children in China and his research dates from 2002. Later. Buijzen investigates the influence of the advertising on child consumption behavior, followed by ^{Valkenburg (2007)}, who investigates the effects of social networks, television and advertising on tweens and teens.

Analysis of publications on child consumer behavior in the afore mentioned historical range shows ^{Robertson as an important author (1974)}, who wrote the article Children and Commercial Persuasion: An Attribution Theory Analysis, one of the mam references in the scientific study of child consumption. However, there are also sets of authors that acquire importance due to their bibliographic coupling, which occurs when the works of a group of authors are published by a journal or magazine. The journal that includes the highest density of topics related to child consumer research is Young Consumer, a British publication belonging to Emerald Group Publishing Ltd., with an H Index of 22, created since 2002 and recently Q1 in the economic miscellany, econometrics and finance. On the other hand, there are orientations adjacent to child behavior in the role of consumer associated with family habits, the influence of advertising communications on product consumption behaviors, the impact of television and social media advertising on the practices of children related to the consumption of brands, and incomplete information in communications in the advertising of baby food, resulting in bad eating habits.

When establishing collaboration among authors' affiliations by country, it is observed that the United States has the highest rate of collaborative work in research on child consumption, followed by the United Kingdom and Australia. The primacy of the North American country is given by a phenomenon of co-authorship in the investigations. This collaboration represents greater productive research activity in the field of child consumption, which is evidenced in the 1007 documents published in the USA, compared to 231 in the United Kingdom and 163 in Australia (Figure 5).

On the other hand, it was found that the co-occurrences of the most used keywords directly related to child consumption are: child, consumer behavior (which, although it is an Anglicism, is used in the British articles), advertising, consumer socialization, and the latter related to obesity (^{Su & Lee. 2010}) (Figure 6). There are direct associations between words like: persuasion knowledge, advergames and children, as well as between advertising literacy, attitudes, and children. but the strongest association is between the words: children, advertising, and obesity.

By observing the analysis of co-occurrences through multidimensional reduction (^{Aria & Cuccurullo, 2017}) the result presents conceptual structures, identifying sets of articles that work on common themes according to the K-means clustering technique (^{Hartigan & Wong. 1979}: ^{Kanungo et al., 2002}). Hie results are represented on a two-dimensional map (Figure 7).

For this analysis, five clusters are observed, categorized from the extraction of common terms. From left to right, the first group integrates words such as voting adults, questionnaires, parent(s), healthy attitudes, practices and healthy knowledge, and attitude towards health. The second group gathers words such as consumer behavior, social behavior, marketing, perception, social networks, networking, consumer research and retail. We will call tins group Online and offline consumer research. The third grouping, together with words like fast food, diet, nutritional value, healthy behavior, food preference, food choice, will be called Healthy promotion. For the fourth grouping, the result includes words such as food industry, television, obesity, advertising, food, drink, food consumption, child behavior, preschool and child nutrition. We will call it Advertising influence on children s food consumption. Finally, group five, with the highest coverage hi research, is made up of words such as: advertising, communication, motivation, clinical studies, cross-sectional studies, controlled studies, decision-making, adults, children, adolescents, parent-child relationship, family, psychological aspects, experiments and eating behavior. We will call tins group Family eating behavior (Figure 8).

From the formation of the clusters, each grouping integrates a set of authors and articles and magazines with more citations. It is generally observed that the topics associated with child consumption, which have been researched and published for decades, are mainly related to food consumption and healthy behavior. Next, the most important topics in the field of research on child consumption are analyzed, for which the main authors, the most consulted documents and the journals with the highest relationship with each of the topics identified will be integrated (Table 5).

Discussion

This document analyzed 1375 documents from 1974 to 2019. with 2597 authors. 2500 author keywords and 1265 additional keywords, identifying the most frequent keywords in studies of child consumption. The bibliometric results show five clusters comprised of the main themes that have characterized research in child consumption. Each identified cluster shows that in this field the studies have been directed at issues related to public health, obesity prevention campaigns and those associated sociodemographic aspects. For this reason, the studies earned out are oriented to the analysis of the infant consumer hi relation to food, food brands and marketing communications, and advertising of food products. But there are few studies aimed at the analysis of services and products for mass consumption, the impact of digital environments, new forms of children's leadership in these spaces, as well as the consumption of luxury brands and products, among other research areas. The journals with most publications on child consumption have a clear health orientation, with a few articles in the top magazines on marketing and consumer psychology.

It is also clear, as hi other scientific fields, that Lathi American countries have a low contribution to the development of research and scientific knowledge on the behavior of child consumers.

On the other hand, according to the proposed thematic conceptual grouping, the cluster with the greatest impact in terms of the number of citations is attitude towards health. which indicates that it has been the most relevant research topic for the development of public policies aimed at the child population, which makes sense if you consider the countries that show the highest number of publications. However, children's behavior on social networks, the consumption of video games and the large number of associated products, available through the Microsoft or Sony operating system platforms, as well as mobile or online applications, result in problems that affect importantly the child population and that have not been investigated by the consumer and marketing psychology. Nor are there enough studies related to the role of boys and girls as influencers in the pin chase of products, the acquisition of paid applications and the contracting of different services by families, neither has then role as consumers in self-managed platforms been investigated, such as Netflix. YouTube. YouTube Kids. Amazon Prime, Fox and Spotify. among other streaming applications to access audiovisual or music content.

While it is true that most research on child consumption is aimed at studying the impact of advertising and marketing in specific communities of this population, and that they are oriented to social marketing, creating campaigns to reduce overweight in children (^{Blanchette et al., 2016}: ^{Carter et al., 2011}; ^{Harris et al., 2009}; ^{Kelly et al., 2008}: ^{Kraak & Story, 2015}; ^{Kubacki et al., 2015}: Kubacki & Szablewska, 2019: ^{Marty et al., 2018}: ^{McAlister & Bettina Cornwell 2012}: ^{Powell et al., 2014}. 2007: ^{Schuster et al., 2015}). it is still necessary to develop knowledge transfer processes, both from consumer psychology and from marketing, for the design of programs that promote responsible consumption hi children and that support various public policies in different regions of the world. Some current examples could show the type of contributions necessary from social marketing, as it is the case of programs based on community coalitions that develop responsibility policies, associated with the marketing planning of brands and aligned with a social purpose, integrating the community, the company and the state, within a regulatory framework that favors informed purchasing both for parents or caregivers, as well as for children (^{Biroscak et al., 2018}: Biroscak et al., 2019: ^{McHugh et al., 2018}). This requires, from the scientific and professional community, a fundamental change in the methodologies and principles with which programs for responsible consumption are designed, where social marketing is integrated with the development of strategies, tactics, activities, indicators and support processes of the program. This requires professionals from different disciplines, including health sciences, interdisciplinary work with marketing professionals, as well as the consideration and evaluation of social marketing, as a central strategy for the achievement of indicators of programs aimed at responsible consumption, especially hi the child population (^{Lefebvre. 2012}).

Thus, the development of these new lines of research is of fundamental importance for the design of public policies for the protection of child consumers and for the responsible development of marketing directed towards children today. It is required that the different academic groups continue developing their lines of study of children's behavior in the face of communication strategies, hi social networks, in the field of video games and. hi general, hi the context of the digital age. The findings will allow not only the conceptual development of child consumer psychology, but the development of legal and commercial regulations for child marketing. Finally, the findings of this bibliometric study are an invitation for scientific journals to continue publishing studies in this field, given its current and future relevance, broadening the analysis in terms of comparability with systematic reviews in the field of consumer psychology and trying to explain some implications of the findings for the formulation of public policies or child consumer protection interventions.

This need is especially important in countries where legislation does not clearly cover children as consumers, and where digital environments are relatively free to access information from the child population. In these contexts, academic research groups should provide valuable studies and information for decision making and the development of regulatory policies for responsible consumption. The study presented in this article shows that this task has not been fully accomplished and that the approach to children as a market and as consumers should be deepened.