The answer is this is not a study, and the audience for this piece is not scientists. This is from scientific american, whose mission is to present easily digested scientific content. Scientific american is written for those interested, but not steeped in, science.

Articles/studies themselves are written for a professional audience, and as such include many jargon terms and require knowledge of advanced methods to fully comprehend. It may be harder for the public to engage with, but if research is dumbed-down in its study/article format, reproducibility would be even harder due to a lack of detail.

Now ask yourself “how many people did they test” and “what statistical test did they use to show significance”.

This popular-press article doesn’t say, and doesn’t have to. Their actual scientific report will have these dry details and be a more formulaic read.

Are you reading the actual study? Because what's linked here isn't a study, it's an article about a study. In other words, it's written by a journalist, not a scientist that worked on the study.

This is not a scientific report of a study, but a popular piece based on multiple studies. In an academic article every material claim has to be supported by data or previous literature. The claims have to be well specified and the study must be (or at least should be) explained in enough detail that reader can understand more or less exactly what was actually done. This tends to make very annoying reading, but also makes it clear that the results very rarely are as straightforward, generalizable and strong as presented in a popular article.

The main study report linked in the article seems to be so well paywalled that it is not available via my university's library nor sci-hub.