Oddly, I cannot find this quote - neither on Google nor on Google Scholar. While there are a few papers on the subject of naturals vs strivers, and while you're use of the text isn't strictly plagiarism, I find it quite disrespectful of you to have not provided a clear link or at least a citation to the original work.

None of the research I checked is attributed to Harvard. The most recent popular work seems to come from University College London.

As for the conclusions you draw, I'll note that all the research I found on the subject lies in the fields of psychology and sociology, in which the "replication crisis" is most profound.

I'm not a psychologist, and I do not intend to disparage the work of those studying this topic. I do however wish to draw your attention to the importance of proper academic methods and that one report (your mysterious Harvard document) does not a fact make.

In closing, I note that you could have avoided all this uncertainty by providing a proper citation.