A jury in Nashville heard this week that Meta once concluded, in its own internal language, that the features keeping teenagers glued to Instagram were “inherently at odds with well-being”, and that the company then chose to say nothing about it.

The line comes from a 2017 document that the state of Tennessee has placed at the centre of its case, and it set the tone for opening statements in a trial that could run for seven weeks.

The case, brought by Tennessee Attorney General Jonathan Skrmetti in the Chancery Court in Nashville before Chancellor Russell Perkins, argues that Meta violated the Tennessee Consumer Protection Act by hiding what it knew and by shipping features designed to hook young users.

It is the latest venue for a fight over Instagram’s addictive design that regulators have been building towards for years, and one of the first to put those questions in front of a jury rather than settle them on paper.

The state points to autoplay, Reels, push notifications, and posts engineered to disappear as the mechanics that, together, encourage compulsive use.

The stakes across the wider litigation have grown steep enough that the numbers now read as abstractions.

Tom Cartmell, arguing for Tennessee, told jurors that Meta’s own product managers had written in 2017 that features such as notifications and infinite scroll worked against users’ well-being, and that the company should warn the public.

“This warning never came,” he said. The state contends that Meta researchers went on to document compulsive teen use, and its links to eating disorders, depression, and self-harm, while leadership left the underlying design in place because it drove ad views.

Much of that argument runs through Mark Zuckerberg. The complaint alleges that Meta’s chief executive was repeatedly warned by employees about research showing Instagram harmed the mental health of young users, and that he declined to fund the work that might have reduced those harms.

No executives were named from the stand during opening statements, though, and the allegation remains the state’s characterisation rather than a finding.

Meta’s lawyer, Kevin Huff, offered jurors the same documents read the other way. The internal research the state calls a cover-up, he argued, is instead evidence of a company that goes looking for problems on its platforms so that it can fix them.

Meta has built tools to limit heavy use of Instagram and to help parents and teachers set boundaries, he said, before landing on the framing the defence will lean on for weeks: “Protecting teens online is a shared responsibility. It takes a village.”

Outside the courtroom the company has struck a similar note, saying it has *“spent a decade building safe, age-appropriate defaults for teens alongside simple tools for parents to set the right boundaries for their family”. *

Meta has spent much of the past year pointing to those design and default settings as evidence of good faith rather than negligence.

If the jury finds Meta liable, the case moves to a second phase before Perkins to weigh penalties and possible changes to the product.

Tennessee is seeking civil penalties of up to $1,000 per violation, a figure that sounds modest until it is multiplied across a teenage user base the size of a state’s, which is why the eventual exposure is so hard to bound and why both sides are treating a liability finding as the moment that matters.

Tennessee is far from alone. Nearly every US state has now filed claims against Meta over youth safety, and more than two dozen suits have been consolidated into multidistrict litigation in San Francisco.

The company already knows how a jury can land, too. In March a Santa Fe jury ordered Meta to pay $375m in a separate New Mexico case built around child exploitation rather than addictive design, and that verdict now hangs over every state trial that follows. The Nashville proceedings continue.

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