Abstract: Virtual influencer endorsements, empowered by artificial intelligence technology, offer a new approach to brand communication and exert outstanding influence on social media platforms. However, research on the relationship between virtual influencer endorsements and consumer engagement remains in its early stages, not only limited in scope but also facing two primary research gaps. First, firms face a unique challenge in leveraging these endorsements to enhance consumer engagement. This challenge arises from a strategic tension in selecting either brand-developing proprietary virtual influencers or collaborating with third-party virtual influencers. However, there is a lack of exploration of the impact of virtual influencer endorsement selection strategies on consumer engagement. Second, existing literature has yet to investigate the underlying mechanisms and boundary conditions. From various theoretical perspectives, virtual influencer endorsement involves several key mechanisms, including the communication cycle, information processing, and relationship interaction. Therefore, understanding the effectiveness of these mechanisms is crucial for addressing the differing brand communication effects generated by different virtual influencer endorsement selection strategies.
In response to these research gaps, based on the communication time, accuracy, and relationships perspectives, this study proposes communication timeliness mechanisms (Study 1), information discrimination mechanisms (Study 2), and relationship-building mechanisms (Study 3) to comprehensively examine the effects and mechanisms of virtual influencer endorsement selection strategies (brand-developing proprietary versus collaborating with third-party) on consumer engagement, and explores key boundary conditions from artificial intelligence technology factors and virtual influencer/consumer factors perspectives, combined with brand communication-related theories and influencer marketing.
Specifically, first, drawing on the research insights on brand awareness in the process of brand communication in marketing, and based on the signal detection theory, this study aims to explore the communication time mechanism of long-term "brand awareness" and "virtual influencer awareness" induced by virtual influencer endorsements selection strategies, and further analyze the moderating effect of the artificial intelligence technology factor (i.e., authenticity level of virtual influencers) and influencer factor (i.e., brand-virtual influencer consistency) (Study 1). Second, grounded in the elaboration likelihood model (ELM), which is widely used in the advertising domain, this study aims to explore the double-edged sword information discrimination mechanism of advertising intrusiveness and information diagnostic induced by virtual influencer endorsements selection strategies selection and examine the moderating effect of artificial intelligence technology factor (i.e., authenticity level of virtual influencers) and consumer factor (i.e., need for cognition) (Study 2). By doing so, it comprehensively understands how consumers distinguish the endorsement information of virtual influencers. Third, following the widely used parasocial interaction theory in the field of social media marketing, this study explores the relationship-building mechanism of consumers in virtual influencer endorsement brand activities, that is, consumer-brand identification and consumer-virtual influencer identification, and examines the moderating effect of artificial intelligence technology factor (i.e., virtual influencer’s agency: fully artificial intelligence-driven versus manual intervention) the authenticity level of virtual influencers and influencer factor (i.e., brand-virtual influencer consistency) (Study 3).
In response to these research gaps, this work makes the following contributions. First, this article focuses on the uniqueness of virtual influencer endorsement selection strategies, thus expanding the scope of brand endorsement research. While existing studies primarily explore the differences between virtual and real influencers in brand communication, few studies examine the specific selection strategies for virtual influencer endorsements. By analyzing this selection strategy, this study enriches the theoretical research system of brand endorsement and provides new topics for further research in this field. Additionally, this study systematically investigates the multiple mediation models, comprehensively revealing the underlying mechanisms, which contributes to understanding the relationship between virtual influencer endorsements selection strategies and consumer engagement and advancing virtual influencer marketing research. Furthermore, this study reveals the boundary conditions related to artificial intelligence technology factors (i.e., authenticity level of virtual influencers, virtual influencer’s agency: fully artificial intelligence-driven versus manual intervention), virtual influencer factor (i.e., brand-virtual influencer consistency), and consumer factor (i.e., need for cognition), thereby facilitating interdisciplinary integration between the fields of influencer marketing, AI technology and psychology. Moreover, this study aims to offer effective guidance for firms in selecting virtual influencer spokespersons, managing interventions for virtual influencer applicability, and implementing artificial intelligence marketing, thereby providing crucial insights for virtual influencer practices.

Key words: brand endorsement, virtual influencer, marketing strategy, consumer engagement, artificial intelligence marketing