Why don't we improve captcha?

Question

I just wrote a self-answered question on the Physics site. The answer is really long, and frankly speaking, it takes some time getting all the diagrams right, researching, making sure the explanations are lucid etc. So, I started yesterday evening (IST) and then I stopped for the night and continued today morning (IST)

This is what I was shown when I tried to publish it:

Now, I am fine with that, I understand: we don't need bots running the sites, we need humans with flesh and blood. But, when I went ahead to tick the box:

It comes right back to being unticked. Now, occasionally if this happens, I am fine with it, but this is happening the third time in a row!

Eventually, it allowed to continue after I tried it in a new window. I don't know the technical aspects of how captcha works, but why is this happening? Is it because of some server error, that this thing happens every time, or is there something else?

Also, the captcha looks pretty outdated. Again, I got no clue on how AI or scripts work, but it seems that a script can be well-equipped to tick a box. So, why don't we get something more advanced and efficient: like the ones where you have to select a letter or tick some images with certain objects in it? Why cant we improve captcha, both error free versions and more challenging ones?

Answer 1

That Captcha is provided by Google, and what it does is much more than having a user check a box. In the background, when you click that checkbox, Google uses all the information it has on the actions of the user to estimate how likely the user is to be a real person compared to a bot. If the estimate is that you're probably a real user, the box is checked and you can continue. If it is low, you get a real captcha (or several after each other) of the really annoying kind with the images that refresh very slowly.

Your case does look a bit like an error on the SE side, or some issue with the Captcha service itself.

If the error isn't due to the SE integration of the Captcha, there are several things this Captcha does not like. If you use Chrome and are logged into a Google account, it should almost always work because Google has a lot of information on you at that point. If you e.g. use Firefox with Adblocker, tracking protection and browse in incognito mode, Google has much less information about you. It is much more likely to consider you a bot then.