Mark Zuckerberg Testifies in Landmark Youth Social Media Harm Trial in Los Angeles

At exactly 9 a.m. on Wednesday, Meta CEO Mark Zuckerberg stepped into a Los Angeles County Superior Court courtroom walking with noticeable stiffness, after a security detail including two U.S. Department of Homeland Security officers escorted him into the building. Presided over by Judge Carolyn Kuhl, the space was overflowing with spectators and reporters, many squeezed shoulder-to-shoulder on benches. Everyone in attendance had gathered to watch Zuckerberg answer to a jury over allegations that Meta’s products put young users at severe, avoidable risk.

The core claims against Meta are clear: Zuckerberg and his team intentionally engineered flagship products Facebook and Instagram to be addictive, and deliberately targeted pre-teens and teenagers with engagement-driving algorithms that have spurred a widespread youth mental health crisis. Wednesday’s testimony marked the opening of a pivotal showdown in a 2023 lawsuit filed by 20-year-old Californian Kaley (identified in court records only by her initials K.G.M.) and her mother, who originally sued Meta alongside YouTube, Snap, and TikTok. The pair alleges Kaley’s compulsive use of the platforms starting in early childhood left her with permanent, severe psychological damage.

After Meta and Google failed to get the entire case dismissed last November, Snap and TikTok chose to resolve their claims out of court. That leaves Meta and Google to face the first of nearly two dozen bellwether trials for social media addiction currently on the Los Angeles court docket. These test cases are selected to represent the claims of a far larger group of roughly 1,600 total litigants, all of whom have sued the same social media brands over similar harm. Every family alleges their children developed depression, body dysmorphia, or died by suicide after becoming hooked on the platforms’ attention-grabbing design. Many of these families were in the crowd Wednesday, eager to see Zuckerberg called to account under oath.

Lead plaintiff’s counsel Mark Lanier opened his cross-examination by immediately putting Zuckerberg’s credibility under intense scrutiny. Lanier systematically dismantled claims the Meta CEO made under oath during January 2024 congressional testimony on child online safety. While Zuckerberg had testified that Instagram bars all users under the age of 13 from joining the platform, Lanier introduced 2015 internal Meta data showing the company already estimated 4 million under-13 users were active on Instagram that year — equal to 30% of all 10- to 12-year-olds in the U.S. Zuckerberg had also previously claimed Meta’s leadership never issued directives to push teams to increase the total amount of time users spend on Meta platforms. Lanier countered with a 2015 goal-setting email from Zuckerberg himself that listed increasing user time as the company’s top priority that year.

To underscore Zuckerberg’s ultimate authority over all Meta decisions, Lanier quoted a line from the CEO’s 2023 interview on the Joe Rogan Experience podcast: “Because I control our company, I have the benefit of not having to convince the board not to fire me,” Zuckerberg told Rogan. On the stand Wednesday, Zuckerberg pushed back, arguing the comment was just a “simplified” retelling of Meta’s actual governance structure.

Throughout hours of testimony, Zuckerberg was strangely evasive even on trivial details and basic definitions. He could not definitively confirm his 2024 congressional testimony had taken place on January 31, for example, and hesitated to agree with Lanier’s simple proposition that addictive substances or activities lead people to engage with them more often. He ultimately hedged: “Maybe in the near term.” When asked to confirm he had made past comments, he relied regularly on the vague, non-committal line: “It sounds like something I would have said.” When confronted with internal documents showing Meta prioritized maximizing “total teen time spent” on its apps, he repeatedly replied, “That’s what the document says.”

Zuckerberg repeatedly fell back on the claim that Lanier was “mischaracterizing” his previous statements. When questioned about old internal emails, he often objected either by noting the message’s age or claiming he had no familiarity with the Meta employees referenced. When asked if he knew Karina Newton, Instagram’s head of public policy in 2021, he answered flatly: “I don’t think so, no.” He also never missed an opportunity to point out when he was not included on an email thread entered as evidence.

Anticipating Zuckerberg’s distant, repetitive talking points — in which he repeatedly framed any increased user engagement as a reflection of the “value” users get from Meta’s products — Lanier early on suggested the CEO had been extensively coached for his testimony. “You have extensive media training,” Lanier said. “I think I’m sort of well-known to be pretty bad at this,” Zuckerberg retorted, drawing one of the only laughs from the packed courtroom. Lanier followed by introducing internal Meta documents that outlined formal communication strategies for Zuckerberg, noting the materials described his team as “telling you what kind of answers to give” even for testimony under oath. “I’m not sure what you’re trying to imply,” Zuckerberg responded. Later that afternoon, Meta lead counsel Paul Schmidt circled back to the topic, asking if Zuckerberg’s role requires more media appearances than he prefers. “More than I would like,” Zuckerberg answered, drawing another round of laughter.

In an oddly meta moment after court resumed from lunch, Judge Kuhl issued a stern warning to all attendees: anyone wearing recording-enabled smart glasses — specifically the AI-powered Oakley and Ray-Ban smart glasses sold by Meta for up to $499 — were required to remove them, since the court bans all audio and video recording of proceedings.

K.G.M.’s lawsuit and the upcoming bellwether trials use a novel legal approach that sidesteps Section 230, the federal law that has long protected tech companies from liability for content posted by third-party users. Accordingly, Zuckerberg stuck to a prepared defense that framed the entire lawsuit as a fundamental misunderstanding of how Meta operates. When Lanier presented evidence that Meta teams worked to increase daily user time on the platforms, Zuckerberg countered that the company had abandoned those goals years ago, or that the metrics cited were never formal company goals, just standard industry competitiveness measurements. When Lanier pressed him on an email from former Meta global affairs president Nick Clegg that called Meta’s age-limit policy “unenforced” and potentially “unenforceable,” Zuckerberg calmly deflected, arguing users regularly find ways to bypass safeguards even as Meta continues to improve its age-verification tools.

Lanier constantly anchored his arguments back to Kaley, noting she created her Instagram account at just 9 years old — five full years before Instagram began requiring all new users to enter a date of birth in 2019. While Zuckerberg was able to brush off questions about internal data pushing Meta to convert pre-teens into long-term loyal users, or Meta’s choice to ignore alarming internal research on the harm of Instagram’s beauty filters, he had no prepared response for Lanier’s grand finale: a billboard-sized tarp stretching across half the courtroom, held up by seven members of the plaintiff’s team, covered in hundreds of posts pulled directly from Kaley’s Instagram account. As Zuckerberg blinked at the giant display, visible only to him, Judge Kuhl, and the jury, Lanier explained it demonstrated the sheer volume of time Kaley poured into the app. “In a sense, y’all own these pictures,” Lanier said. “I’m not sure that’s accurate,” Zuckerberg replied.

After Lanier finished his cross-examination, Schmidt led Zuckerberg through redirect, framing Meta as a platform that fosters connection and protects free expression. The Meta founder quickly regained his comfortable rhythm on the stand. “I wanted people to have a good experience with it,” he said of the company’s platforms. He added a moment later: “People shift their time naturally according to what they find valuable.”