Oh, so that is how those headphones work. I had an MRI a long time ago as a child, and really can’t remember much about it at all.

Was it really the headphones being low quality or is the MRI just so loud that any headphones would sound terrible?

And this is why double negatives are in general frowned upon in the English language, because they make the content much more difficult to understand.

You had me in the last sentence… sadly

Although it would probably be fitting to describe it as a subset. If you look at vision, then it is a spectrum that includes everyone. Even blind people. If you are looking at blindness, then it is a subset of the vision spectrum that only includes people that meet certain other criteria, i.e. below a certain threshold of vision. Same for autism disorder. Every human is on a mentality spectrum, and autism is a subset of that.

cheap for a human to complete but expensive for a computer to beat

This is the reason and logic. There are no advanced algorithms deciding your “humanness.”