1) There was no link to the actual studies done. The writer didn't even list the title or authors of the meta-study she's referencing. That's sloppy journalism. I don't trust sloppy third-hand accounts of what a study says. I always go to the study itself to see what it says. The article does provide the issue where the study can be found. I'll go to the university library when I have time and look it up, but I could find the article itself from my home computer if I had the title.
2) I outright laughed at the assertion that the benefit of literary fiction is its psychological insights into characters, which the writer asserts that genre or popular fiction doesn't have. Anyone who's read sci-fi authors like Neal Stephenson, Terry Pratchett or Philip K Dick, or mystery authors like, Michael Connelly, Ian Rankin or even John Sandford, would be shocked to learn that they aren't reading books with psychological insights into the characters, be it heroes or villains. Good grief, Philip K Dick has readers thinking, and hard, about who among humans today would pass the storyline's empathy test (not to mention questioning what existence and being means at all) in "Do Androids Dream of Electric Sheep?" That takes some serious psychological insight. So maybe it's something else that inspires more empathy in "literary" fiction readers than psychological insights alone. The themes addressed, and how they're addressed, in literary fiction versus genre fiction would be a damned good place to start looking if you ask me.
3) Another problem with the article: The writer keeps jumbling "genre" fiction with "popular" fiction, and there is a difference. Many titles in the popular fiction category are non-genre works, and not all genre fiction is "popular" fiction. Some clarity of terms is in order.
So I'm not buying the argument made in the article. It could be that the writer didn't analyze the original paper about the subject properly. That happens far too often with journalists writing about findings in articles from Science or Nature. Or it could be that the study writers were off-kilter in their assessments.
The only way to know is to read the original paper(s).
Moved to respond to the proper post.