Over the arc of time, I’m not sure that an accurate characterization is that humans have been getting dumber and dumber. If that were true, we must have been super geniuses 3000 years ago!
I think what is true is that the human condition and age old questions are still with us and we’re still on the path to trying to figure out ourselves and the cosmos.
That's my theory, anyway.
I definitely think we are smarter if you are using IQ, but are we less reactive and less tribal? I'm not so sure.
Here is one paper: https://www.nature.com/articles/s41598-020-62877-0
"Although the longitudinal sample was small, we observed an important effect of GPS use over time, whereby greater GPS use since initial testing was associated with a steeper decline in hippocampal-dependent spatial memory. Importantly, we found that those who used GPS more did not do so because they felt they had a poor sense of direction, suggesting that extensive GPS use led to a decline in spatial memory rather than the other way around."
In my opinion, this is a uniquely human thing because we're smart enough to develop technologies with planet-level impact, but we aren't smart enough to use them well. Other animals are less intelligent, but for this very reason, they lack the ability to do self-harm on the same scale as we can.
Another way of saying it: the problem we should be focused on is not how smart the AI is getting. The problem we should be focused on is how dumb people are getting (or have been for all of eternity) and how they will facilitate and block their own chance of survival.
That seems uniquely human but I'm not a ethnobiologist.
A corollary to that is that the only real chance for survival is that a plurality of humans need to have a baseline of understanding of these threats, or else the dumb majority will enable the entire eradication of humans.
Seems like a variation of Darwin's law, but I always thought that was for single examples. This is applied to the entirety of humanity.