A court has heard claims Meta intentionally hooked a generation of children on Facebook and Instagram, as the biggest legal challenge the social media platform has faced began on Tuesday.

A jury in Oakland, California will spend the next six weeks wading through claims by top attorneys from several US states, and lawyers for the social media company, that at turns rebutted the other as the trial opened.

A lawyer for California claimed Meta found “millions” of 11 and 12-year-olds were on Instagram and “it did little to keep them off”.

Meta’s representative said just over 100,000 such users were found, and also argued that social media addiction does not exist.

After the state lawyer said Meta knew its platforms hurt teen mental health, Meta’s side said it was being ignored how many more teens had good experiences

The trial stems from a lawsuit filed in 2023 by 29 US states, including California and New York, in which they claim numerous violations of federal and state privacy laws for children.

Not only are the states seeking billions of dollars from Meta, they are demanding it make changes to Instagram and Facebook, including ending “like” counts and infinite scroll.

The trial started off on Tuesday with a battle of words and facts.

Paul Schmidt, a lead attorney for Meta in the trial, directly addressed an internal research report that Megan O’Neill, a lead attorney for California, made part of the states’ opening arguments.

The Meta document O’Neill showed the jury found that “1 in 5 teens says Instagram makes them feel worse”.

Schmidt said: “That sounds pretty bad.”

“What else does the document say?” Schmidt went on. “That 41% of teens said it made them feel better and another 41% said it had no effect.”

Schmidt also worked to poke holes in the states’ argument that Meta had not only failed to stop users under the age of 13 from using its platforms, but that it intentionally “hooked” teens and children as users of Facebook and Instagram, or that they were designed to be addictive.

As for Meta being able to verify the age of every user on its platform, Schmidt argued that the very privacy laws Meta was being accused of violating in the case prevent it from saving and using the data it would need to effectively track underage users.

When it comes to addiction, Schmidt argued a point that Meta has put forward in at other litigation this year: that social media addiction does not exist.

“There can be no dispute that Meta has recognised people struggle, or can struggle, with their use of social media, and has come up with tools to try and address that,” Schmidt said.

Yet, he pointed to past statements from chief executive Mark Zuckerberg and head of Instagram Adam Mosseri that not only were Facebook and Instagram not designed to be addictive, scientific research has not yet come to support the idea that an addiction to social media is possible.

O’Neill’s opening arguments seemed to challenge Schmidt’s argument.

She relied heavily on information found in millions of documents provided in the case from Meta, including internal research, employee emails, and chat logs, all the way up Zuckerberg.

One such piece of internal research stated about young people and Instagram: “Teens have an addict’s narrative about use.”

In another that O’Neill pointed the jury to, Meta found “product features designed to increase time spent are inherently at odds with well-being and take away from people’s ability to focus on activity that adds value to their lives”.

Despite Meta’s awareness of potentially negative impacts, O’Neill argued that Meta targeted young people as users of Facebook and Instagram and went out of its way to “assure the public that its platforms were safe for kids”.

Meta’s business model could be summed up this way: “Hook the users; hold them for as long as they can; harvest their data; hide the truth from the public when making public statements,” she said.

She said that throughout the trial, it would become clear that what Meta said publicly about its platforms, and what its internal research showed, were very different.

“Meta said it put safety over profits, but hid the reality that, time and again, when it came to make a decision, profits won.”