Zuckerberg Testifies in Bellwether Trial Over Instagram's Alleged 'Addiction by Design'

Meta Platforms CEO Mark Zuckerberg is scheduled to testify before a jury in a pivotal bellwether trial in Los Angeles Superior Court, addressing allegations that Instagram was intentionally engineered to foster compulsive use among young individuals. This initial test case, which could establish a legal precedent for thousands of consolidated actions, centers on claims that the platform's design contributed to the severe mental health deterioration of the 20-year-old plaintiff, identified as K.G.M.

The plaintiff's legal argument is founded on the theory of 'addiction by design,' asserting that features such as infinite scrolling were implemented specifically to maximize user engagement and advertising revenue, irrespective of the impact on adolescent mental well-being. K.G.M. began using YouTube at age six and Instagram at age eleven, subsequently alleging that this prolonged, addictive exposure led to depression and suicidal ideation. Prior to this trial, both TikTok and Snapchat reached confidential out-of-court settlements with K.G.M. in December 2025, positioning Meta and Google as the primary defendants facing the jury.

Legal observers are drawing comparisons between this litigation and the mass legal actions against the tobacco industry in the 1990s, which resulted in significant settlements and regulatory shifts. Plaintiffs contend that social media companies knowingly engineered addictive products and concealed internal research on potential harm to maximize profits, framing the platforms as 'digital casinos.' This strategy seeks to pivot the legal focus from content liability, often protected under Section 230 of the Communications Decency Act, toward product design defects, a novel theory with global regulatory implications.

Meta's defense counters by emphasizing parental responsibility, suggesting the plaintiff's mental health challenges stemmed from a difficult home environment rather than platform architecture. The defense also disputes the clinical recognition of 'social media addiction' and questions the direct causation between platform use and mental health outcomes. Testimony from Instagram chief Adam Mosseri, which referenced internal debates over teen safety and business 'trade-offs,' may have supported the plaintiff's argument regarding foreseeability.

The jury, overseen by Los Angeles Superior Court Judge Carolyn Kuhl, will determine whether the applications were defectively designed to maintain minor addiction and if that design substantially contributed to the alleged harm. This bellwether case, projected to last six to eight weeks, is the first of nine selected actions in California testing this legal theory, with approximately 1,600 similar plaintiff actions consolidated within the process. The outcome is expected to serve as a critical indicator for related lawsuits, potentially compelling broad changes to platform architecture, including features like constant push notifications and recommendation algorithms, and setting a new standard for executive accountability in the technology sector.