Zuckerberg testifies in landmark social media addiction trial

Mark Zuckerberg testified for nearly eight hours on February 18, 2026, at the Los Angeles County Superior Court Spring Street Courthouse. It was his first time testifying about child safety before a jury. The trial is a bellwether case — meaning its outcome will directly shape how more than 1,600 similar pending lawsuits from families and school districts are resolved.

The case centers on a 20-year-old 🌴California woman identified as 'Kaley' (K.G.M.) who alleges she began using YouTube at age 6, Instagram at age 9, and spent as many as 16 hours on Instagram in a single day as a teenager. Her lawsuit claims addictive design features — including beauty filters, infinite scroll, auto-play, and algorithmic engagement maximization — caused her to develop depression, body dysmorphia, anxiety, and suicidal thoughts. She also alleges bullying and sextortion on the platforms.

Plaintiff attorney MLMark Lanier deployed an unconventional approach at trial: at one point having six lawyers unspool a 35-foot-wide collage of hundreds of Kaley's Instagram selfies in the courtroom and asking Zuckerberg to examine her account's history. Lanier also cited internal Meta documents showing the company set goals to increase Instagram daily engagement time from approximately 40 minutes in 2023 to 46 minutes by 2026, and evidence that all 18 external consultants Meta hired to assess beauty filters raised concerns.

Zuckerberg testified that Meta does not seek to make Instagram addictive and that the company is focused on building 'a community that is sustainable.' He said he believes the existing scientific record has not proved that social media causes mental health harms — a position consistent with his 2024 congressional testimony. He acknowledged that some users lie about their age to join the platform, admitted underage users exist, and said Meta is working to find and remove them.

The legal innovation at the core of the case is the use of product liability law — the same framework used against Big Tobacco and defective vehicles — to bypass Section 230 of the Communications Decency Act (1996), which shields tech platforms from lawsuits based on what users post. Plaintiff attorneys argue that the harm comes not from user-posted content but from deliberately designed product features: infinite scroll, auto-play, beauty filters, notification systems. The argument treats Instagram as a defective consumer product, not a content host.

TikTok and Snapchat settled before trial for undisclosed amounts, leaving only Meta (Instagram) and Google (YouTube) as defendants. YouTube's chief executive Neal Mohan was removed from the witness list during the trial because plaintiff attorneys said they were 'running out of time' and would instead call YouTube's Vice President of Engineering, Cristos Goodrow. Instagram head AMAdam Mosseri testified the prior week, saying he thinks there can be 'problematic use' of social media but doesn't consider it clinical addiction.

The trial has international policy implications: Australia has banned social media use for those under 16. Denmark, Spain, and Malaysia are considering similar bans.

Multiple U.S. states including 🌴California have passed laws requiring stronger age verification and limiting algorithmic targeting of minors. Congress has passed the Kids Online Safety Act through the Senate, but it has not come before the House, and the trial's outcome could affect its prospects.

DWDarrell West, senior fellow at the Brookings Institution's Center for Technology Innovation, said the trial 'represents the test of a novel legal theory' because 'for 30 years, tech platforms have been shielded from legal liability by congressional legislation.' He noted the Big Tobacco comparison directly: the 1990s tobacco lawsuits established that companies had internal knowledge of harm, targeted young users, and concealed that information — the same allegations being made against Meta in this trial.