Because that’s all we seem to have measured. So, hypothesizing about whether there’s any other finer-grained causation in the data is the logical next step.

Me personally, I have immense trouble believing that passively watching entertainment has the same effect on working memory as, say, playing video games. And even within video games there’s probably a distinction between the more story-driven games that are a lot more passive to play, versus puzzle games that require active reasoning, versus games that test reaction time or memorization, etc.

(Full disclosure: I was a child of the 80’s and raised by a Nintendo and my computer. I think I turned out ok but I don’t have any alternative childhood to compare to)

> I was a child of the 80’s and raised by a Nintendo and my computer.

I was also in this boat: My siblings and I watched hours and hours of television when we grew up, but we didn't start watching as toddlers. My own anecdata seems similar to yours, which is unable to verify what happens when you watch hours of brain rot from age 1 and up.

> And even within video games there’s probably a distinction between the more story-driven games that are a lot more passive to play, versus puzzle games that require active reasoning,

Otoh, story-driven games might be teaching social reasoning skills.

puzzle games cover a lot of ground. Some are as mindless as instagram scrolling.

Certainly would be interesting to test.

Totally, I didn't say it was illogical to hypothesize. GP made a factual assertion that there is a difference.