Court Filings Allege Meta Suppressed Causal Evidence That Facebook and Instagram Harm Teens' Mental Health

By Jeff Horwitz

Unredacted court filings in a class-action lawsuit brought by U.S. school districts claim Meta stopped internal research after it produced causal evidence that Facebook and Instagram harmed users' mental health.

According to documents obtained through discovery, Meta researchers in 2020 ran a study called 'Project Mercury' with the survey firm Nielsen to measure the effects of temporarily deactivating Facebook and Instagram. Internal results reportedly showed that participants who stopped using Facebook for a week reported lower levels of depression, anxiety, loneliness and social comparison.

Instead of publishing the findings or pursuing follow-up research, the filings say Meta discontinued the project and internally attributed the negative results to the 'existing media narrative' surrounding the company. Privately, however, staff reportedly told then-head of global public policy Nick Clegg that the results were valid.

'The Nielsen study does show causal impact on social comparison,' an unnamed researcher wrote, and another staffer warned that concealing such findings would be comparable to how the tobacco industry handled harmful research.

Broader allegations in the filing

The filing, submitted by Motley Rice on behalf of school districts suing Meta, Google, TikTok and Snapchat, accuses the companies of knowingly hiding internal assessments of product risks from parents, educators and users. The complaint levels a range of charges — some aimed primarily at Meta — including allegations that platforms encouraged underage use, failed to address child sexual abuse material adequately, and sought to expand teen usage during school hours.

1. Meta allegedly designed youth-safety features to be ineffective or seldom used and blocked testing of tools it feared would reduce growth.
2. Internal documents reportedly said Meta required users to be caught multiple times attempting to traffic people for sex before removing them, calling the threshold 'a very, very, very high strike threshold.'
3. Meta is said to have recognized that optimizing for teen engagement increased exposure to harmful content but pursued that optimization anyway.
4. The company allegedly delayed efforts to stop child predators from contacting minors because of growth concerns and pressured safety teams to circulate arguments supporting inaction.
5. A 2021 text message attributed to Mark Zuckerberg reportedly stated he would not prioritize child safety above other initiatives, such as building the metaverse; the filing also says Nick Clegg's requests for more funding for child-safety work were rebuffed or ignored.

The filing also alleges that other platforms engaged in influence efforts: for example, TikTok is said to have sponsored the National PTA and internally celebrated its ability to shape the group's public messaging.

Company response and next steps

Meta spokesman Andy Stone responded that Project Mercury was stopped because its methodology was flawed and said the company has worked 'diligently to improve the safety of its products.' Stone disputed the filing's characterizations, calling them 'cherry-picked quotes and misinformed opinions,' and said Meta's teen safety measures are effective and that accounts flagged for sex trafficking are removed when identified.

The underlying Meta documents cited in the filing remain sealed; Meta is opposing their unsealing. A hearing on the filing is scheduled for January 26 in U.S. District Court for the Northern District of California.