Last I heard it started in the 90s. Although a lot of horrifying graphs do have their inflection point the year the iPhone came out.

If you're referring to the few-point difference between 2012 and 2018 in the first chart here: https://www.oecd.org/en/publications/pisa-2025-results-volum... I think that's more likely to be statistical noise. Keep in mind that PISA was originally normed to a mean of 500 and standard deviation 100. Even the more obvious drop after 2018 (I blame the pandemic) down to a mean of 466 on the reading test in 2025 isn't all that huge in absolute terms, though definitely statistically significant with the large sample they have.

A factor, certainly, but culture, including the culture around education, are arguably bigger factors (which social media is also a vector for modifying; medium is the message and all that).

Social and cultural expectations and conventions are extremely important. Even in supposedly laissez-faire Western countries where traditional cultural expectations have withered to the point of laxity, people still live their lives according to convention and expectation, even if those conventions and expectations are increasingly vulgar and dictated by powerful interest. (Indeed, the fertility crisis is determined largely by patterns of convention. It used to be that, for most people, it was expected that you would marry and have children earlier rather than later. Now, our cultural expectations actually penalize that kind of behavior. You're supposed to "find yourself", "play the field", or "build up your career" first.)

Human beings operate more by convention than by moral reasoning. Society needs an environment demands good things from them. Even when we know what the right or good course of action is through moral reasoning and discernment, it is very helpful for social convention and culture to support those choices.

The law is also traditionally a source of guardrails that help people attain better lives.