Revolutionizing consumer insights: the impact of fMRI in neuromarketing research

Abstract

This study performs a comprehensive bibliometric (performance analysis) and thematic content analysis of global research in "neuromarketing or consumer neuroscience" and "functional magnetic resonance imaging or fMRI." Utilizing the PRISMA framework and R package software, we analyzed thirty-six Scopus-indexed articles. The USA and California Institute of Technology emerged as leading contributors, with Rangel, A., and Reimann, M., as notable authors. Prominent themes include 'advertising,' 'product,' 'price,' and 'brand', with the “Journal of Consumer Psychology” and “Journal of Neuroscience” being key publications. The most cited article is "Marketing actions can modulate neural representations of experienced pleasantness," with 620 citations. In addition, fMRI has been used to study consumer behavior (impulsiveness, reward, emotion, decision-making, and memory) toward marketing stimuli such as price (WTP), advertising (celebrity endorsement, MSV), product (packaging design), and brand (Halal logo, label, and personality). This study provides an invaluable literature review matrix and detailed insights into the current trends in global neuromarketing research utilizing fMRI. This study highlights the significant impact of fMRI in both academic and commercial realms, offering new insights for targeted marketing and consumer behavior research. It provides valuable guidance for developing more effective advertising strategies, understanding consumer decision-making processes, enhancing business performance, and collaborating academically.

Introduction

The evolution of functional magnetic resonance imaging (fMRI) techniques has revolutionized marketing research, providing deeper insights into consumer behavior than traditional methods [98]. Early marketing studies used surveys and questionnaires, which were cheap and included a lot of people. However, self-reported data can be biased [17, 23], and these types of data are not accurate enough to explain what people actually do and want [63]. Focus groups, guided by group dynamics and lacking generalizability, provided qualitative insights through guided discussions [54, 118]. Behavioral observations offered real-time data on consumer interactions with products but did not reveal underlying cognitive processes [6]. Currently, the growing interest in better understanding marketing stimuli-evoked consumer behavioral patterns has led to the use of methods adapted from neuroscience, i.e., fMRI; such practices are called "neuromarketing" [32, 33, 105].

Neuromarketing, a cross-disciplinary field merging marketing, neuroscience, and psychology, involves applying consumer neuroscience techniques to understand consumer responses to marketing stimuli [55, 107]. When fMRI came along, it was a big deal because it measures brain activity by looking for changes in blood flow. It also has a high spatial resolution that lets researchers pinpoint neural responses to marketing stimuli [21]. Unlike traditional methods that capture expressed preferences, fMRI uncovers subconscious processes and true emotional reactions, often revealing discrepancies between stated and actual feelings [17, 23]. Early fMRI studies identified neural correlates of decision-making, brand perception, and emotional responses to ads [42, 57]. Combining fMRI with technologies like eye tracking provides a comprehensive view of visual information processing, while real-time fMRI neurofeedback training influences preferences and decision-making [7, 14]. These advancements enable the neuro-optimization of product design and branding to align with neural responses associated with positive emotions, fostering emotional branding and loyalty [64, 95]. fMRI data also predict ad campaign success and informs personalized marketing strategies based on individual neural responses, enhancing engagement and conversion rates [88]. Integrating traditional marketing and neuromarketing approaches yields more precise and high-quality insights into consumer behavior, aligning with their actual actions in the market [28, 50, 102].

Studies have highlighted the preferred use of fMRI in consumer neuroscience research, indicating its significance in understanding neural processes related to consumer behavior [23]. The application of fMRI techniques has challenged traditional views by revealing neural dissociations between brand and person judgments, underscoring its potential to provide valuable insights into consumer decision-making processes [117]. Furthermore, the use of fMRI in neuromarketing research has been acknowledged as a critical element, with a focus on understanding the neural basis of consumer decision-making and neuro-forecasting [69, 71, 73, 75]. Although fMRI is widely utilized in neuromarketing studies, it is essential to consider the practical aspects, such as the cost and equipment requirements, which may hinder its widespread application in commercial settings [70, 95]. The potential use of fMRI is limited by its expensive nature and the need for large equipment, which restricts its practical application in neuromarketing studies [62]. Therefore, the integration of fMRI with other neuroimaging techniques, such as electroencephalography (EEG), has been recognized as valuable for providing high spatiotemporal resolution mapping of brain activity, further emphasizing the significance of multimodal functional neuroimaging in consumer neuroscience [116].

Recognizing the increasing interest in neuromarketing, various studies have already explored scientific production in this field [10, 53]. However, a distinctive gap exists as no prior research has systematically mapped the research output related to "neuromarketing or consumer neuroscience" and "functional magnetic resonance imaging or fMRI" within the Scopus (SC) database. This study sets itself apart from other reviews by focusing on global academic research trends on SC, specifically concerning studies utilizing fMRI in neuromarketing or consumer neuroscience research from 2007 to 2021. Thus, the study aims to address this gap in scientific literature. The objective is to extensively identify global academic research trends in “neuromarketing OR consumer neuroscience” AND “functional magnetic resonance imaging OR fMRI” and to present a comprehensive thematic content analysis of the selected articles for this study in a concise conclusion. The research objectives (ROs) of this bibliometric and thematic content analysis are outlined as follows:

• (1) Identifying the growth of annual scientific publications based on journals' outputs.

• (2) Determining the overall performance, including productive countries, institutions, journals, and authors.

• (3) Identifying the most prominent themes/keywords in "neuromarketing OR consumer neuroscience" AND "functional magnetic resonance imaging OR fMRI."

• (4) Identifying the most-cited articles for consideration in future studies.

• (5) Providing a summary of thematic content analysis of selected articles for this study.

To achieve the above ROs, five research questions (RQs) were formulated to guide the structure of the analysis and gain a thorough understanding of the existing scientific research in the analyzed domain. These research questions were thoughtfully designed to shed light on key areas of interest and contribute to the improvement of knowledge in the relevant areas, as follows:

• (1) What is the rate of annual growth in scientific publications within this field, if any?

• (2) Who are the leading contributors in terms of (a) countries, (b) academic institutions, (c) journals, and (d) authors in this area of study?

• (3) What key themes or keywords frequently appear in the original articles related to this field?

• (4) Which articles have received the most citations in this research area?

• (5) What key insights or information are presented in the content of the chosen articles?

This study is organized as follows: “The fMRI literature review” section provides the literature review of the study. “Methodology” section presents the materials and methods that have been used in this study. “Results” section is dedicated to the relevant articles' bibliometric analysis and thematic content analysis. “Discussion” section provides a discussion of the paper. “Conclusion” section presents the conclusions, limitations, and future trends.

The fMRI literature review

The fMRI is a widely used tool in neuromarketing research, particularly for studying consumer behavior and decision-making processes [21, 42, 107]. Despite its less frequent use compared to other neuroscientific tools (e.g., EEG and ET), fMRI is commonly used when consumers are presented with product images and asked to make purchase decisions [10, 95, 98]. This non-invasive technique allows researchers to estimate neural activity at a high spatial resolution within seconds, making it valuable for understanding neural correlates of consumer behavior [23, 54, 113]. The use of fMRI in neuromarketing has been particularly emphasized for its ability to measure brain activity associated with consumer preferences, attitudes, and decision-making processes [47], and its potential to offer objective evidence of neural processing of advertising [98]. In addition, fMRI has been used to discriminate between different types of decisions, identify brain areas influencing financial decisions, and investigate brain activations associated with personal involvement [60, 92, 99]. It has become popular due to its unique insights into brain functions, potential to identify brain mechanisms, understand individual differences, and improve behavior prediction in neuromarketing [54, 62].

Although fMRI's high sensitivity to brain responses makes it a powerful technique for studying consumer psychology related to branding [14], destination image [13], Hala logo [15], decision-making processes [99], and trustworthiness evaluations of online offers [62]. For instance, Al-Kwifi [14]utilized fMRI to investigate attitudes related to high-technology products and brand switching, demonstrating fMRI's role in detecting attitudes. Moreover, fMRI technology has been used to understand consumer behavior in specific cultural contexts, such as the influence of the Halal logo on Muslim consumers [15]. In addition, Hubert et al. [62] delved into the neurophysiological insights on consumer impulsiveness in online settings, demonstrating fMRI's common use in neuromarketing to understand individual differences in consumer behavior. This is supported by Alsharif et al. [17], who highlighted fMRI's main applications in advertising research, particularly in studying brain regions and processes related to consumer behavior. Cao and Reimann [36] emphasized the integration of functional neuroimaging with other methodologies in consumer neuroscience, highlighting the validity and explanatory power of fMRI research in understanding consumer behavior.

According to the literature, many researchers and scholars have acknowledged the fMRI tool as the best technological innovation ever developed to carry out experiments/research on the human brain [37, 101]. The interest in neuroimaging technology and its usage has been constantly growing since its introduction in the mid-1980s [45, 77]. The fMRI tool is a metabolisms technology that depends on the vessels' blood flow to measure the brain signals activity [21, 42, 80]. Because of its excellent spatial accuracy and it does not use radioactive material as in the positron emission tomography (PET) tool, today, the fMRI is considered the most creative, powerful, and revolutionary tool used in neuromarketing research [90], allowing recording the underneath neocortex of the consumer's brain activity within 1–10 mm of deep structures in the brain. In addition, the advantage of the fMRI tool is the ability to record the activity in the deep brain regions by three-dimensions technology, which gives researchers more accurate information to study and analyze the deep activity regions, which leads researchers and scholars to consider the fMRI as the revolutionary or creative tools in neuroscience and neuromarketing research [38, 54]. The fMRI tool is used in marketing research to measure consumers’ reactions toward brands, advertising, and so forth [16, 18, 31, 119]. For example, it is used in advertising to measure the neural correlates of consumers’ behavior toward advertising and branding. However, this tool is quite huge and requires a big place to set up; moreover, it is impossible to use fMRI it in real market conditions, also it is very expensive [3, 42]. Concerns regarding interpretative approaches and potential issues in fMRI data analysis in consumer neuroscience research have been raised [36]. However, integrating fMRI with other neuroscientific methods and behavioral data has been proposed to enhance the validity of functional neuroimaging research in consumer neuroscience [36].

Methodology

Bibliometric and systematic review protocol

The application of bibliometric analysis serves to substantiate global academic research trends [22, 110]. This involves assessing the outputs of academic publications, including the identification of the most productive countries, academic institutions, journals, and authors, as well as evaluating the number of citations to discern trends in the application of "neuromarketing OR consumer neuroscience" AND "functional magnetic resonance imaging OR fMRI." The study's structure adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework outlined by Page et al. [85], aiming to uncover relevant articles for an overview of current literature trends and provide a thematic content analysis of selected articles to address existing gaps (see Fig. 1). To address the research questions, this study initiates by extracting articles from the SC database. Additionally, the study follows the guidance of [8] to conduct a comprehensive bibliometric analysis, detecting and listing the most productive countries, academic institutions, journals, and authors and providing concise descriptions of each analyzed parameter.

Fig. 1

The PRISMA flowchart of the article’s selection process

A bibliometric analysis in various areas, for example, in neuromarketing [19, 20], service quality and healthcare [12], human hormones [51], geopolitics [114], sustainable development goals (SDGs) [109], healthcare and service quality [11, 12], online learning [1, 2]blockchain [112] are widely used VOSviewer software. Instead of VOSviewer software, this study uses R Package software to create a descriptive bibliometric and visualization map for the fMRI technique and neuromarketing research. The biblioshiny web-based interface structure helps identify performance analysis. The findings guide researchers and practitioners in neuromarketing and consumer neuroscience. Table 1 shows the inclusion and exclusion criteria for selecting articles from the SC database to answer the research questions.

Table 1 Inclusion and exclusion criteria

Figure 1 shows data mining from the SC database was conducted in March of 2022. Because the SC database is the largest database of abstracts and citations, it covers a broad range of themes, as well it is covering more themes that might not be available in the Web of Science (WoS) [53]. This study focuses on articles using fMRI in neuromarketing or consumer neuroscience research. It extracted thirty-six articles between 2007 and 2021 using a query for title, abstract, and keywords: TITLE-ABS-KEY ((neuromarketing OR consumer neuroscience) AND (functional magnetic resonance imaging OR fMRI)). The selection process involves four steps, as follows: (i) identification, (ii) screening, and (ii) selection of relevant articles (see Fig. 1). To provide a better understanding of the processes and tools used for the study, the analytical structure of this study is provided in Fig. 2.

Fig. 2

The analytical structure of this study

Classification criteria

We classified the papers based on their research topics and the characteristics of their experimental paradigms, including study design and the type of stimuli used. Table 2 presents the classification of the articles by research topics. Our classification approach began with the well-known marketing stimuli framework, which includes product, price, and promotion. Each of these primary categories was further divided into sub-topics, with common keywords identified for each sub-topic. This structured approach facilitated a comprehensive and detailed analysis of the literature, allowing us to systematically categorize and compare studies based on their focus areas and methodologies. By employing the marketing mix as a foundational structure, we ensured a consistent and relevant framework for classifying research, making it easier to identify trends and gaps in the existing body of knowledge. In a similar manner, we considered the main characteristics of the experimental paradigm.

Table 2 Classification criteria of marketing stimuli

Task

The most common protocol involves displaying a list of stimuli (pictures, videos, or TV ads), but an increasing number of studies contain more sophisticated tasks, such as like/dislike, decision-making, or willingness of the participants to pay. Measures of memorization (e.g., encoding, restoring, and retrieving) and ease of recall.

Stimuli

As shown in Table 2, the majority of articles (19 articles) have used advertising and brand stimuli (e.g., TV ads, MSV, success prediction, image, favorableness, brand logo, brand personality, brand perception, celebrity endorsement, halal logo vs. non-halal logo). This was followed by articles used to study the product characteristics and preferences (e.g., involvement, package design, decision-making, liking/disliking), whereas the six articles were used to study various areas such as decision-making, reward, and self-control of individuals. Finally, three articles have been used to study the WTP and pricing.

Participants

The combination of research questions and types of stimuli often indicates the primary target population for a study. Articles that detail participant recruitment and categorization range from balanced samples, which consider factors like age, gender, and income, to studies focusing on specific groups, such as males or females. Some studies target habitual consumers of a particular product category, while others compare habitual consumers with new consumers. The number of participants is selected based on initial hypotheses, the number of trials, expected effect sizes from existing literature, and power analysis. In this review, participant numbers vary widely, from 4 to 65, reflecting the diverse methodologies and research aims across different studies.

Results

Growth and main information of publications

We extracted 36 articles from 2007 to 2021 using the search terms “neuromarketing OR consumer neuroscience” AND “functional magnetic resonance imaging OR fMRI.” Table 3 shows the main information about articles, published in 29 scientific journals, featuring 236 unique keywords and contributions from 130 authors, averaging 3.82 authors per document and 4.59 co-authors per article, indicating high collaboration. The collaboration index was 3.91, and the articles had a high average citation rate of 78.06 citations per article.

Table 3 Main information about selected articles for this study

Figure 3 shows the annual publications remained stable at 1 to 4 per year, while cumulative publications increased significantly from 1 to 34. This suggests sustained interest and a focus on quality over quantity in the research area. Despite minor fluctuations in annual publications, the consistent rise in cumulative publications indicates a growing body of knowledge and potential for future growth. Institutions and funding bodies should consider these trends to encourage higher annual outputs while maintaining research quality. Overall, the robust cumulative growth highlights the field's enduring relevance and impact.

Fig. 3

The annual scientific productions

Bibliometric analysis

Productive countries and institutions

Table 4 highlights global contributions to neuromarketing and consumer neuroscience research using fMRI, with the USA leading with 23 articles and 2475 citations, mainly from the California Institute of Technology. Germany and Denmark follow, with notable contributions from Otto-Von-Guericke University and Aarhus University, respectively. Other countries like Canada, the Netherlands, Switzerland, and Spain each published two articles. Institutions are categorized into three clusters: the top being the California Institute of Technology (four articles), a middle group of four institutions with two articles each, and a final group of five institutions with one article each.

Table 4 The productive ten countries and academic institutions of scientific production

This distribution underscores the USA's dominant position in this research field, both in quantity and impact, as evidenced by the high citation count. Germany and Denmark also demonstrate significant contributions, reflecting strong research programs in their leading institutions. The clustering of institutions by output highlights centers of excellence and potential hubs for future collaboration. This analysis not only showcases the geographical diversity in neuromarketing and consumer neuroscience research but also points to potential areas for increased international collaboration and knowledge sharing.

Figure 4 shows the countries’ scientific productions and collaboration map among countries. As shown in Fig. 4a, the most productive country is the USA (orange color), while the least productive country is Mexico (Red color). Figure 4b illustrates the collaboration among countries, wherein the most collaboration between two countries was between the USA and Germany, Denmark and Switzerland, and the USA and Canada, with two links/frequencies for each of the two countries. The rest of the countries only have a frequency/link between them.

Fig. 4

a Countries’ scientific production; b Countries’ collaboration map

Leading authors

Table 5 shows the most prolific authors with at least two publications in the “neuromarketing OR consumer neuroscience” and “functional magnetic resonance imaging OR fMRI” research. It has been observed that Rangel, A., affiliated with the California Institute of Technology, and Reimann, M., affiliated with the University of Southern California, have contributed four articles each, with 1413 and 134 total citations. In addition, Rangel, A. published his 1st article in 2008, while Reimann, M. produced his 1st article in 2012, followed by Langleben, D.D., who published three articles with 103 total citations in his first article in 2009. The rest of the authors have contributed two articles each. The interesting point is that although Plassmann, H. and O’doherty, J.P. have published two articles each, their articles have the second-highest citations.

Table 5 Contribution of articles by authors (two articles at least)

Figure 5 shows the visualization map of the most relevant authors, countries, and sources. This network map illustrates that the larger size of rectangles means the higher frequency of a certain author, country, and source within the collaboration network. In addition, the thickness of the connection line varies from one author to another based on the number of connections. In this context, Rangel, A., Reimann, M., and Langleben, D.D. are the most productive authors from different institutions.

Fig. 5

The most productive authors by countries and sources

Figure 6 demonstrates the distribution map of Lotka’s Law (dashed line). The x-axis illustrates the number of articles written, while the y-axis shows the percentage of authors representing different areas. It can be noticed from the figure that more than 90% of total authors have published at least one article in the “neuromarketing OR consumer neuroscience” and “functional magnetic resonance imaging OR fMRI.” Approximately less than 10% of total authors have published more than one article. Both lines are close to each other, referring to more authors who wrote only an article.

Fig. 6

The distribution of scientific productivity

Leading journals

Table 6 reveals the leading journals that have published articles in "neuromarketing OR consumer neuroscience" and "functional magnetic resonance imaging OR fMRI" research. It has been observed that the most productive journals are J. Neurosci. and J. Consum. Psychol., with three articles each, 793 T.Cs and 424 T.Cs, respectively. Followed by four journals that have published two articles each: J. Mark. Res., Hum. Brain Mapp., J. Econ. Psychol., J. Prod. Brand. Manag. has published two articles each, with 85, 54, 52, and 26 T.Cs, respectively. At the same time, the rest of the journals have published one article each. The interesting point is that even though the journal Proc. Natl. Acad. Sci. U.S.A. is in the 7th level in the list, with one article; it published the second most-cited articles with 620 T.Cs, which makes it the highest-cited journal compared with the number of publications. The journal Psychol. Sci. and Dev. Cogn. Neurosci. in the 8th and 9th rank in the list, but both have the fourth and fifth highest-cited articles, respectively.

Table 6 The most contributive journals (> = 11 TCs)

Keywords analysis

The authors analyze keywords in articles to provide a comprehensive interpretation of content [4, 87]. Wherein the keywords frequencies have been expressed numbers, a higher number means a higher occurrence between a couple of keywords [94, 108, 111]. This study used the R Package to conduct an occurrence analysis of 111 keywords in 36 articles published in 26 journals. Keyword analysis is crucial for providing broad claims and evaluating trend topics in specific areas [43], such as neuromarketing and functional magnetic resonance imaging or fMRI.

Table 7 and Fig. 7 show the keywords with the highest occurrence: functional magnetic resonance imaging/fMRI, followed by the words “consumer neuroscience” and “neuromarketing.” For example, “functional magnetic resonance imaging or fMRI or functional MRI” is the most occurrence word with 22 occurrences, followed by “consumer neuroscience” and “neuromarketing” with eight occurrences each. “Reward,” “brands” or “branding,” and “decision making” or “decision-making” or “decision behavior” or “decision” with four occurrences each. The rest of the authors’ keywords have less than three occurrences. Therefore, it can be concluded that “neuromarketing OR consumer neuroscience” has used “functional magnetic resonance imaging OR fMRI” tool to study, explore, and predict the consumer’s behavior (i.e., decision, choice, attention, emotion, and reward) toward brands and advertisements. Finally, the findings were expected.

Table 7 The most 16 occurrences of authors’ keywords (> = 2 occs)

Fig. 7

Shows the word cloud of the author’s keywords

Figure 8 displays a Sankey diagram displaying relevant institutions, keywords, and authors in inter-institution collaboration. Larger colored circles indicate higher frequency, and connection lines vary based on affiliations, themes, and authors. The thickness of the connection line varies between affiliations, themes, and authors based on the number of connections. Key keywords include functional magnetic resonance imaging, consumer neuroscience, and neuromarketing.

Fig. 8

Most occurrences of keywords by institutions and authors

Figure 9 shows the most prominent topics according to co-word analysis (authors’ keywords) in the "neuromarketing OR consumer neuroscience" and "functional magnetic resonance imaging OR fMRI" research from 2007 to 2021. "fMRI" was led cluster 1 (red color), with a betweenness score of 4.263, of maintains a network of interconnections with most of the topics in the network. "Neuromarketing" and “consumer neuroscience” with a betweenness score of 3.407 and 2.525; whereas "health communication" and "advertising" were the themes with the highest proximity with betweenness scores of 2.243 and 1.471, which were defined as the thematic network.

Fig. 9

Co-word analysis (author keywords)

Figure 10 illustrates two clusters (e.g., red and blue clusters). For example, we can notice a relationship between some words in each cluster. The red cluster reveals more relevant words to each other, which means most publications belong to this cluster. At the same time, the blue cluster shows fewer words mean fewer publications.

Fig. 10

Shows the conceptual structure map of the keywords plus

Conversely, the dendrogram depicted in Fig. 11 illustrates the hierarchical arrangement and interrelationships among the concepts identified through hierarchical clustering. This visual representation allocates significance to each element according to the clusters and gages the associations among them. Essentially, each element represents a set of keywords associated with the concepts of "neuromarketing" and "fMRI."

Fig. 11

Topic dendrogram

The authors used "Keywords plus" to track the development of themes over time (see Fig. 12). The authors have selected “Keywords plus” as a method with parameters of five as minimum frequency words and five as the number of words per year. We can see that “neuromarketing OR consumer neuroscience” and “functional magnetic resonance imaging OR fMRI” were related to priority journal (year 2009) and normal human (year 2010) terms. In 2011, new terms emerged, such as decision-making, adolescent, brain mapping, adult, and male. Neuroimaging and human experiment terms were highlighted in 2013. “Magnetic resonance imaging”, “article”, “human”, “female”, and “functional magnetic resonance imaging” terms emerged in 2014. In 2016, three terms appeared: physiology, nuclear magnetic resonance imaging, and brain, but “attention” and “young adult” terms were highlighted in 2017. Advertising theme has emerged in 2018.

Fig. 12

The trends of topics

Citation analysis

Citation analysis is crucial for researchers and scholars to understand global academic trends, providing insights into the most-cited articles or papers within a specific theme, like neuromarketing [5, 22]. The analysis of 36 articles using the fMRI tool in "neuromarketing or consumer neuroscience" research provides valuable references for future researchers and practitioners. Table 8 shows the most-cited articles using fMRI to study consumer behavior toward marketing stimuli, with more than 20 T.Cs. As indicated in Table 8, the article titled "Marketing actions can modulate neural representations of experienced pleasantness," authored by Plassmann et al. [90], has the highest total citations among others, totaling 620 T.Cs. This is followed by the article titled "Orbitofrontal cortex encodes willingness to pay in everyday economic transactions," also by Plassmann et al. [89], with 563 T.Cs. As shown in Table 8, there is a large gap in the total citations between the 2nd article and 3rd. Wherein the title “Aesthetic package design: A behavioral, neural, and psychological investigation” has 249 T.Cs, with 19.154 average T.Cs per year, which was written by Reimann et al. [96]. The title in the 4th position is " From Neural Responses to Population Behavior: Neural Focus Group Predicts Population-Level Media Effects" has 177 T.Cs, with 16.091 average T.Cs per year, which was written by Falk et al. [48]. The titles "The neural mechanisms underlying the influence of pavlovian cues on human decision making" and " How we relate to brands: Psychological and neurophysiological insights into consumer-brand relationships" have 131 and 129 total citations, which were written by Bray et al. [34] and Reimann et al. [97], respectively. In addition, four articles have total citations between 50 and 100 citations, while the rest articles have less than 50 T.Cs.

Table 8 The most globally cited articles (> 20 T.Cs)

Co-citation network of authors

For the analysis of the co-citation network, R Package software has been used. The instructions recommended by Aria and Cuccurullo [24] were followed to map the co-citation network of the top thirty-six articles. The findings enabled the determination of four clusters having high correlations between them, as depicted in Fig. 13. The purple cluster is the largest cluster, which was led by McClure et al. [79]. The blue cluster was dominated by Knutson et al. [71]. Reimann et al. [97] dominated the green cluster, while the red cluster was dominated by Plassmann et al. [91]. Despite the fact that these clusters dealt with different aspects of “neuromarketing OR consumer neuroscience" and "functional magnetic resonance imaging OR fMRI", they are highly interrelated.

Fig. 13

Co-citation network of authors

Co-citation of papers

Table 9 illustrates the co-citation of papers, wherein the title “Neural predictors of purchases” has led the cluster 1 (red cluster), which was written by Knutson et al. [71]. Cluster 2 (blue cluster) was led by Bartra et al. [29], which has written the article titled “The valuation system: a coordinate-based meta-analysis of bold fMRI experiments examining neural correlates of subjective value.” The title “How we relate to brands: Psychological and neurophysiological insights into consumer-brand relationships” has led the cluster 3 (green cluster), which was written by Reimann et al. [97]. Cluster 4 (purple cluster) was led by the article titled “Branding the brain: A critical review and outlook” by Plassmann et al. [91]. But clusters 5,6,7, and 8 have equal citations between the two papers.

Table 9 Leading paper of each cluster

Topics of interest and thematic analysis

Thematic content analysis of selected papers

Table 10 provides a summary of the status of the "neuromarketing OR consumer neuroscience" and "functional magnetic resonance imaging OR fMRI" research and the type of data being used, showing that researchers have started to integrate the fMRI tool in the neuromarketing or consumer neuroscience field since 2007.

Table 10 Trends in "neuromarketing or consumer neuroscience" and "functional magnetic resonance imaging or fMRI" research

Proposed flowchart of using fMRI in marketing research

The fMRI integration in neuromarketing research provides a sophisticated method for understanding consumers' unconscious emotional and cognitive reactions to marketing stimuli [21]. The approach integrates neuroscience principles with marketing strategies to uncover insights beyond traditional methods, starting with clear research objectives (ROs) (see Fig. 14). The ROs are crucial as they guide the entire project, ensuring that every step taken is aligned to understand specific consumer responses to the marketing mix. Objectives should be SMART: Specific, Measurable, Achievable, Relevant, and Time-bound, ranging from assessing emotional reactions to new product designs to evaluating cognitive load in response to pricing strategies [58, 86]. Following an objective setting, hypotheses are developed based on existing theories, literature, or outcomes from previous campaigns. These hypotheses act as educated guesses that the research aims to test, such as predicting that certain advertisements will trigger activity in brain areas associated with emotional engagement [66].

Fig. 14

Flowchart of using fMRI in research

The selection of participants is another critical step, aiming to ensure the study's results apply to the broader target market. This involves detailed demographic criteria setting, ethical considerations like informed consent, and methodologies to ensure participant diversity [26].

Experimental design is where the methodology for exposing participants to marketing stimuli and capturing data is outlined. This phase considers the stimuli (images, videos, etc.), control conditions, and the sequence of exposure, tailored to exploit fMRI technology's capabilities while considering its limitations, such as the need to minimize participant movement [13, 15]. Before the experiment, participants undergo a briefing to understand the process and reduce any potential anxiety. This includes explaining the fMRI procedure and the experience during scanning. Equipment calibration is essential at this stage to ensure the fMRI accurately captures brain activity [78].

The actual fMRI scanning involves presenting the marketing stimuli to participants in the scanner, capturing data on their brain activity. This step requires precise coordination to align stimuli presentation with the scanning protocol, ensuring accurate and reliable data collection [79]. Post-experiment procedures include debriefing participants to provide closure, gather feedback, and ensure their well-being. The raw fMRI data then undergo preprocessing to correct for artifacts and prepare it for analysis, a crucial step for data quality and reliability [25]. The data analysis phase employs statistical techniques to decipher brain activity patterns in response to the marketing stimuli, aiming to link these patterns to specific emotional and cognitive processes [56]. This is where the scientific investigation reveals insights into consumer behavior, necessitating expertise in neuroscience and data analysis [9, 93]. These insights are then compiled into a comprehensive report that translates complex neuroscientific findings into actionable marketing insights. The report aims to be accessible to non-experts, explaining the implications of brain activity for consumer behavior and potential marketing strategies.

Finally, the insights gained are applied to refine marketing strategies. This could involve adjusting advertising to align better with emotional triggers identified in the study, modifying product designs, or tailoring pricing strategies based on the perceived value. The ultimate goal is leveraging these deep insights to create marketing campaigns that resonate with consumers on a subconscious level, thereby enhancing engagement and effectiveness.

Discussion

Neuromarketing is an interdisciplinary field that integrates marketing, neuroscience, and psychology to investigate consumer behavior. By applying neuroimaging tools such as fMRI, researchers aim to analyze and predict neural responses related to consumer emotions, attention, attitudes, and decisions toward marketing stimuli, including brands and advertisements. This study focuses on articles that utilize fMRI in neuromarketing to understand consumer behavior, adhering to the PRISMA framework for systematic selection and analysis of pertinent articles. From the SC database, 36 articles published between 2007 and 2021 were extracted and analyzed using bibliometric tools and Biblioshiny for global research trends.

The study's first objective was to examine the overall production of academic research in this field. The analysis revealed a fluctuating number of publications annually, with no clear trend of growth or decline, indicating an inconsistent but ongoing interest in neuromarketing research. The field has expanded with contributions from a diverse range of disciplines, including psychology and marketing. Collaboration networks have also become more complex, with cross-institutional and international partnerships becoming more common, highlighting the interdisciplinary nature of contemporary consumer neuroscience research.

The second objective identified the USA as the leading contributor with 23 articles, led by the California Institute of Technology. Germany and Denmark followed, with significant contributions from Otto-Von-Guericke University and Aarhus University, respectively. Interestingly, despite having only one publication, Mexico's article was highly cited, highlighting the potential impact of individual contributions. The USA also demonstrated extensive international collaboration, particularly with Germany, Canada, Denmark, and Switzerland. Leading journals in this domain include the Journal of Neuroscience and the Journal of Consumer Psychology, with American universities dominating author contributions. Notable authors include Rangel, A., Reimann, M., and Langleben, D.D., alongside significant contributions from international scholars.

The third objective focused on identifying the most frequent keywords and research themes. "Functional magnetic resonance imaging" or "fMRI" was the most common keyword, followed by "consumer neuroscience" and "neuromarketing." Key research themes included "neuroeconomics," "advertising," and "health communication," highlighting the diverse applications of neuromarketing research.

The fourth objective highlighted [90] article on neural representations of pleasantness as the most cited work, emphasizing the orbitofrontal cortex's role in economic transactions. This underscores the relevance of specific neural regions in understanding consumer behavior.

For the fifth objective, an analysis of 36 articles revealed trends in neuromarketing and fMRI research since 2007, offering a foundational guide for future studies. This analysis identified key areas for exploration and potential under-researched marketing activities, providing a roadmap for further research and potential replication under various conditions. Furthermore, the use of fMRI in studying marketing stimuli has yielded significant insights into how various factors like advertising, branding, pricing, and products influence consumer behavior at the neural level. Research using fMRI has demonstrated that advertising and branding can activate brain regions associated with emotion, memory, and reward, such as the orbitofrontal cortex, which is linked to pleasantness and decision-making. Studies on pricing reveal neural correlations between perceived value and the activation of areas related to pain and reward, indicating that high prices may trigger negative emotional responses, while discounts can enhance reward processing. Product-related research has shown how sensory and functional attributes of products engage different neural circuits, affecting consumer preferences and choices. Overall, fMRI provides a powerful tool to uncover the underlying neural mechanisms of consumer responses to marketing stimuli, offering a deeper understanding of how these factors drive decision-making and behavior.

Despite the growing body of research, emerging countries have not significantly contributed to this field. The high costs associated with fMRI, the lack of available tools in universities, and the cost of conducting neuromarketing research in public institutions are significant barriers. Additionally, there may be a lack of neuromarketing experts in these regions. To address these challenges, it is recommended that scholars and researchers from emerging countries explore global research trends in neuromarketing. This could enrich the body of knowledge and ensure their studies are considered in future research, potentially leading to more inclusive and comprehensive advancements in the field.

Bibliometric analysis involves examining the citation patterns, publication trends, and collaboration networks within the literature, while thematic content analysis focuses on the key themes and topics explored in these studies. By comparing these bibliometric and thematic trends, we can observe the field's transition from foundational, exploratory research to more sophisticated, integrative studies. Early research laid the groundwork by identifying key brain regions and basic neural mechanisms. In contrast, recent studies leverage advanced technologies and interdisciplinary approaches to address more nuanced questions, reflecting a maturation of the field. This evolution highlights the increasing complexity and depth of consumer neuroscience, as researchers move beyond simple mappings of brain activity to understand the dynamic interplay between neural processes, psychological factors, and environmental influences in shaping consumer behavior.

To recapitulate, it has been noted that emerging countries do not contribute by publishing articles in the “neuromarketing OR consumer neuroscience” and “functional magnetic resonance imaging OR fMRI” research. Latter findings have led authors to infer several reasons for the lack of using fMRI in neuromarketing experiments/research in emerging countries: (a) the high costs of using fMRI tools to conduct the experiment might stop the researchers; (b) a lack of the fMRI tool in universities stops the development of methodologies and frameworks; (c) the cost to conduct neuromarketing research by using the fMRI experiment in public universities which has fMRI tool, and maybe lack of neuromarketing experts [52]. Therefore, we encourage scholars/researchers from emerging countries to explore the global academic research trends in neuromarketing research, which can enrich the body of knowledge, and their studies can be considered in future research.

Conclusion

General conclusion

This study offers an in-depth bibliometric analysis of academic research on "neuromarketing OR consumer neuroscience" and "functional magnetic resonance imaging OR fMRI," reflecting the growing interest in using neuroscience tools like fMRI in marketing to understand consumer behavior. Utilizing the PRISMA framework and R package software, this analysis delves into global academic trends, identifying key contributors in terms of countries, institutions, authors, and journals, as well as emerging themes and trends in neuromarketing research.

The study aimed to examine the overall production of academic research in neuromarketing, revealing fluctuating annual publication numbers, indicating inconsistent but ongoing interest. The USA emerged as the leading contributor, with California Institute of Technology at the forefront, followed by Germany and Denmark. Despite having only one highly cited publication, Mexico highlighted the impact of individual contributions. The USA showed extensive international collaboration, especially with Germany, Canada, Denmark, and Switzerland. Leading journals included the Journal of Neuroscience and the Journal of Consumer Psychology, with notable authors like Rangel, Reimann, and Langleben. Frequent keywords included "fMRI," "consumer neuroscience," and "neuromarketing," with key research themes like "neuroeconomics," "advertising," and "health communication." The most cited work was Plassmann et al. [90] article on neural representations of pleasantness, emphasizing the orbitofrontal cortex's role in economic transactions. An analysis of 36 articles since 2007 identified trends and under-researched areas, with fMRI studies revealing how advertising, branding, pricing, and products influence consumer behavior by activating brain regions associated with emotion, memory, reward, and decision-making.

Overall, this comprehensive overview of global academic research in neuromarketing and fMRI from 2007 to 2021 provides valuable insights for researchers. It not only outlines the foundational aspects of neuromarketing but also suggests future research directions, contributing significantly to the understanding of this evolving field.

Theoretical and practical implications

The integration of fMRI in marketing research provides a robust theoretical framework for understanding the neural underpinnings of consumer behavior. By pinpointing neural predictors of purchasing decisions, fMRI contributes to the broader field of neuromarketing, enhancing the theoretical models of how consumers process and respond to marketing stimuli. This aligns with theories in neuroeconomics that explore the neural basis of decision-making and economic behavior. The insights gained from fMRI studies can inform models of consumer behavior, emphasizing the roles of emotional and cognitive processes in shaping preferences and choices. Additionally, understanding the neural correlates of visual and sensory stimuli, such as packaging, offers theoretical advancements in the study of consumer perception and attraction.

Practically, fMRI provides a powerful tool for marketers to assess and refine their strategies. The ability to observe brain activity in response to marketing stimuli enables a more nuanced understanding of consumer reactions, facilitating the development of more effective advertising and product designs. By integrating fMRI data with other neuroimaging and biometric techniques, researchers can obtain a comprehensive view of consumer responses, enhancing the predictive power of marketing models. However, the practical deployment of fMRI in marketing must navigate several challenges, including high costs, complex data analysis, and the need for interdisciplinary expertise. Furthermore, addressing ethical concerns is critical to ensure the responsible use of neuroimaging data, particularly in safeguarding consumer privacy and preventing the misuse of technology.

Limitations and future directions

Despite efforts to mitigate methodological shortcomings, this study encountered several limitations, highlighting opportunities for future research. The study primarily utilized the SC database, the largest abstract indexing database, and focused on English-language articles to maximize coverage. This approach contributes valuable insights for future bibliometric research. The study outlines several research questions (RQs) that future studies could address, particularly in terms of global collaboration in neuromarketing and consumer neuroscience using fMRI. However, fMRI is just one of many tools available in this field, alongside EEG, fNIRS, and others.

Future research in neuromarketing and consumer neuroscience should expand database utilization beyond the SC database to include non-English publications for a more comprehensive view of global trends. Diverse methodological approaches integrating EEG, fNIRS, and eye-tracking with fMRI are necessary to gain multifaceted insights into consumer behavior. Encouraging global collaboration and inclusion, particularly from emerging countries, is crucial for resource sharing and capacity building. Comprehensive bibliometric analysis over extended periods can map research evolution and predict future directions. Under-researched areas like digital marketing, sustainable branding, and cross-cultural behavior need exploration to broaden neuromarketing applications. Longitudinal studies tracking behavioral and neural changes over time can reveal the stability of marketing effects. Leveraging technological advancements in neuroimaging and data analysis can improve the precision and predictive power of studies. Lastly, focusing on practical applications and ethical considerations ensures neuromarketing's real-world relevance while protecting consumer privacy and autonomy.