Can AI outperform humans on Instagram? Evidence from engagement and growth metrics

Purpose This study aims to examine how AI-generated and human-managed Instagram accounts perform as competing interactive marketing actors. It provides an empirical comparison of their overall engagement rates, passive and active interaction patterns, and follower growth efficiency. Design/methodology/approach Utilizing a matched-pair comparative design, the research analyzes objective behavioral marketplace data from 204 matched pairs (408 accounts) on Instagram. The design strictly controls for content typologies and follower tiers, applying non-parametric statistical analysis to evaluate live platform metrics. Findings Overall engagement rates and passive interactions (average likes) are statistically indistinguishable between AI and human creators. Crucially, H3 was not supported; we found no evidence that human accounts receive more comments than AI accounts. Active conversation is constrained across both groups by a structural floor effect and audience disclosure bias. However, AI-led accounts demonstrate significantly higher growth efficiency, acquiring more followers per post. Practical implications AI influencers optimize top-of-funnel audience acquisition and growth efficiency but face a friction bottleneck in active engagement. Marketers should deploy synthetic creators for rapid scalability while implementing specific conversational tactics to overcome consumer hesitation toward disclosed profiles. Social implications This paper highlights digital dehumanization and synthetic parasocial relationships. Algorithmic scaling alters consumer trust, shifting social media from genuine human connection to optimized synthetic influence. Originality/value This paper offers a rare natural marketplace benchmark for synthetic influencer marketing. It advances Social Presence Theory within interactive marketing by proving that algorithmic platform dynamics can equalize behavioral engagement, demonstrating that human authenticity no longer holds a monopoly on user interaction.