Not related to the content of the article, but am I the only one bothered with the way the article spell ranges: "six to 15 minutes", "Twelve of 18 men", "six of 24 females" ...
It is in the APA style guide: "In addition to using words to express numbers below 10, use words to also express: Numbers beginning a sentence, title, or text heading" https://owl.purdue.edu/owl/research_and_citation/apa6_style/...
If you’re unsure which modifier to write and which to express numerically, try it both ways. Be sure the way you express the numbers is in the clearest way possible.