از اثربخشی بازاریابی دهان‌به‌دهان الکترونیکی تا خرید تکانشی: تبیین نقش میانجی ارزش ادراک‌شده و تعامل مشتری در میان کاربران نسل Z اینستاگرام

EXTENDED ABSTRACT



Introduction: Generation Z, as the first cohort of true digital natives, constitutes over one-third of the global population and has emerged as a pivotal consumer segment in contemporary marketing research. Their daily immersion in social media platforms, particularly Instagram-with its rich visual and interactive affordances- has fundamentally reshaped the pathways through which marketing communications translate into purchasing behaviors. Among these pathways, Electronic Word-of-Mouth effectiveness (eWOM effectiveness) has gained prominence as a credible, peer-driven information source capable of influencing consumer decisions. However, while prior studies have largely focused on the direct effects of eWOM effectiveness on impulsive buying, the underlying mechanisms through which eWOM effectiveness exerts its influence remain underexplored, especially within the context of Generation Z on Instagram.

Drawing upon the Stimulus-Organism-Response (S-O-R) framework, the Elaboration Likelihood Model (ELM), and the Dual-System Theory, this study proposes a dual-pathway mediation model in which perceived value and customer engagement serve as sequential and parallel mediators in the relationship between eWOM effectiveness and impulsive buying. Specifically, three research hypotheses are addressed: (H1) eWOM effectiveness has a direct positive relationship with impulsive buying; (H2) customer engagement mediates the relationship between eWOM effectiveness and impulsive buying; and (H3) perceived value mediates the relationship between eWOM effectiveness and impulsive buying.

Methodology: This applied, cross-sectional, quantitative study employed a descriptive-survey design and was conducted among Generation Z consumers (born 1997–2012) residing in Isfahan, Iran. Using a non-probability convenience sampling method, data were collected via an online questionnaire distributed through Telegram and Instagram during winter 2025–2026. A total of 569 valid responses were retained after rigorous screening for incomplete responses, uniform patterns, and duplicate IP addresses. The sample comprised 62.6% females, with a mean age of 21.74 years (SD = 2.99). Standardized scales were utilized: the 9-item Impulsive Buying Scale (Rook & Fisher, 1995), the 2-item Perceived Value Scale (Eggert & Ulaga, 2002), the 2-item eWOM effectiveness Scale (Kim et al., 2018), and the 9-item Customer Engagement Scale (Vivek et al., 2014) encompassing conscious attention, enthusiastic participation, and social connection. Given the violation of multivariate normality (Mardia’s coefficient = 63.443, CR = 77.228), the present research employed bootstrapping with 5,000 resamples and bias-corrected confidence intervals for all structural equation modeling analyses using SPSS 24 and AMOS 24. Model fit was assessed via multiple indices, including χ²/df, GFI, AGFI, CFI, TLI, IFI, PNFI, PCFI, and RMSEA, along with the Bollen-Stine bootstrap test.

Discussion and Results: Descriptive statistics and Pearson correlations revealed significant positive associations between eWOM effectiveness and all study variables, though the direct correlation with impulsive buying was relatively weak (r = 0.140, p < 0.01). Perceived value and the three dimensions of customer engagement showed stronger correlations with impulsive buying, particularly social connection (r = 0.372, p < 0.01), hinting at potential mediation.

The initial structural model indicated that the direct path from eWOM effectiveness to impulsive buying (β = 0.04, p > 0.05) and the direct path from perceived value to impulsive buying (β = -0.038, p > 0.05) were not statistically significant. Consequently, these paths were removed from the final model. The revised model demonstrated excellent fit: χ²(8) = 13.971, GFI = 0.992, AGFI = 0.978, CFI = 0.993, TLI = 0.986, IFI = 0.993, RMSEA = 0.036, and Bollen-Stine bootstrap p = 0.579, confirming that the model adequately fits the data.

Path analysis revealed that eWOM effectiveness significantly predicted perceived value (β = 0.156, p < 0.05) and customer engagement (β = 0.128, p < 0.05). Perceived value, in turn, strongly predicted customer engagement (β = 0.566, p < 0.01), and customer engagement significantly predicted impulsive buying (β = 0.484, p < 0.01). The bootstrapped indirect effects confirmed two significant mediation pathways: (1) the indirect effect via customer engagement alone (β = 0.088, 95% CI [0.026, 0.170]), and (2) the serial mediation path through perceived value followed by customer engagement (β = 0.061, 95% CI [0.021, 0.123]). Both confidence intervals excluded zero, confirming full mediation. Thus, H1 was rejected, while H2 and H3 were supported, though H3 was supported only in the serial mediation context rather than as simple mediation.

These findings indicate that eWOM effectiveness does not directly trigger impulsive buying among Generation Z on Instagram. Instead, eWOM effectiveness first enhances consumers’ cognitive evaluation of value, which subsequently fuels deeper engagement—manifested as conscious attention, enthusiastic participation, and social connection—and it is this heightened state of engagement that ultimately precipitates unplanned, impulsive purchases. This serial mechanism aligns with the S-O-R model, where eWOM effectiveness serves as a stimulus, perceived value and engagement represent the organism’s cognitive and affective processing, and impulsive buying is the behavioral response. The lack of a direct effect also underscores that in visually saturated, algorithmically curated environments like Instagram, raw eWOM effectiveness information must be transformed into meaningful, interactive experiences before it can override self-control mechanisms.

Conclusion: This study advances the understanding of digital consumer behavior by uncovering a serial mediation mechanism through which eWOM effectiveness influences impulsive buying among Generation Z on Instagram. Contrary to common assumptions, the present research reveals that eWOM effectiveness’s impact is fully indirect, operating through a dual-pathway process: first through perceived value as a cognitive foundation, and then through customer engagement as an affective-behavioral catalyst. The serial pathway- eWOM effectiveness → perceived value → customer engagement → impulsive buying- highlights the critical role of engagement as the proximal driver of impulsive responses. Practically, these results urge marketers to design eWOM effectiveness content not merely to inform, but to actively stimulate interaction and community participation. Creating visually compelling, relatable, and interactive content that fosters comments, shares, and immersive browsing can amplify perceived value and engagement, thereby increasing the likelihood of spontaneous purchases. Methodologically, future research should adopt longitudinal designs and integrate objective behavioral data to strengthen causal inferences. Cross-platform comparisons (e.g., TikTok vs. Instagram) and moderation analyses by personality traits or product categories would further enrich the theoretical framework.