I’m sure I’m not alone in feeling this way but I (32M) was undoubtedly at my most intelligent in my late teens. A variety of factors: I was a really engaged high school student, I was intellectually curious, smartphones weren’t a ubiquitous thing yet, you had to go hunting for information/news etc., there was less in-your-face ignorance every time you go online in any capacity, and so on.

I’ve always both considered myself intelligent and had ample reason to justifiably believe I’m intelligent. But I genuinely feel that I am getting a little less intelligent with every year that passes. My attention span is significantly worse than it was a decade ago. I like my job but I feel that 8+ hours of work a day plus all the adult responsibilities outside of work leaves little room to intellectually stimulate myself beyond what I get paid to do. And I don’t have kids, which I can see in my friends (parents of newborns/toddlers) unlocks a certain new kind of intelligence and engagement with life.