A girl’s grades drop every summer. There’s an alarming explanation. | One family’s concern is a warning sign for kids around the world.

That’s a bit of a myth:

The history of summer holidays is clouded with myths. One popular idea is that school children have a long summer holiday (six weeks for most pupils in the UK) so that they could help work in the fields over the summer. But the current school system was developed over the course of the 19th century, when English farms were increasingly mechanised and having children helping with the harvest would only have been necessary for a small percentage of the population. Besides which, a brief glance at the farming calendar tells you that a holiday that ends at the start of September is not going to be much use for bringing in the harvest in the early autumn. So whatever the origin of six weeks off at the height of summer is, it’s not for the sake of farmers.

We should also distinguish between two types of historical explanation: people do all kinds of things for all kinds of reasons, but they tend to keep doing the things that create good results. However, they may not know what’s causing those results, and it may have nothing to do with why they initially decided to engage in that behavior. So you can have people all over converge on a certain behavior without a consistent explanation for why they’re doing it—and popular explanations (even if historically informed) may have nothing to do with why the behavior actually persists.

Can confirm. I live here and I don’t go outside during the summer because it fucking sucks, and everyone is an idiot. Humidity makes people do stupid shit.