These kind of studies are dubious. The PhD report could have been generated by an LLM in about a day, and no one would know any better.

It works like this:

Take any hypothesis. And have a lot of verbiage around it with dubious experiments to "statistically" validate it. and write a giant report which would eventually turn into a book.

Steve Pinker and his likes excel in this kind of stuff. Psychology/Sociology and sometimes economics are filled with these sorts of studies.

It is more persuation than science.

And one could could argue that science itself is a certain kind of persuation.