Not just psychology. Even the claims within this very paper are hard to test. Anything involving evolution is almost impossible to test. The "science" is mostly

Not just psychology. Even the claims within this very paper are hard to test. Anything involving evolution is almost impossible to test. The "science" is mostly observational and descriptive and arrived at through logical guesses. If all of "science" involved strict rigor to the "scientific method" we'd have none of the social sciences like anthropology or evolutionary psychology. This paper is simply pointing out differences in view points. I think the general idea in psychology is real though, the paper gets into details which is a bit pedantic. In fact the paper literally states that they are all in agreement that all brains evolved from a common ancestor. This would be the "reptile" and for sure common features in our brain such as serotonin stem from this "reptile" brain. Psychology gets a lot of bad rep for the reproduction crisis, but evolution should largely be worse because we can't experimentally verify anything without time travel. So it's not like this paper is about true science defeating pseudo science. It's all really speculative.