The Silent Seraph
The stories, as I stated, were all extrapolated from Biblical stories. "Unfamiliar", as used in the study, merely means they changed "sea" into "mountain" and "God" into "magic", but the story's premise and events remain otherwise identical. That, coupled with the fact that they were easily able to distinguish between non-biblical fiction and reality shows that the researchers have created a biased system designed to trigger familiar pathways to produce manipulated results.
I concede that it would be informative to conduct further research involving fantastical stories that bore no resemblance whatsoever to the biblical ones. I just couldn't tell from your initial post whether or not you realized that some of the narratives were quite different from what the Bible says. I personally think that the stories were altered enough to yield valuable information about what children exposed to religion are willing to believe.
You make a good point to bring up how easily the children could tell the difference between non-biblical fiction and reality. However, the examples presented during that part of the study involved
familiar people/characters, so of course it was easy for them to make that distinction. The results from the story-based portion suggest that the distinction is not quite as easy for children who have been exposed to religion when they aren't familiar with the character, and have not had the chance to be told that said character is purely imaginary or that he/she was actually a historical figure.
The Silent Seraph
In addition, the study doesn't show what they claim it does, even disregarding their flawed methodology. It shows that secular children are closed-minded, and more apt to dismiss views contradicting their own, whereas religious children are more open-minded, and more apt to provide justification for unexplained events. Shortly put, the secular children would be those more likely to dismiss evidence which contradicted long-held beliefs, whereas religious children would be more likely to suspend disbelief and find explanations. This, interestingly enough, could serve as an explanation for why the champion minds of scientific advancement are primarily religious.
I don't think it really demonstrates much of anything about whether secular or religious children are more closed-minded. They both had to make a definite decision about the status of each character as real or fictional. In order to make a decision they had to close their minds to one possibility, but that doesn't mean they're closed-minded in the sense that they are unwilling to consider other possibilities when given a valid argument against their choice.
I don't know if that last sentence is true or not, but I won't dismiss it if you produce good evidence for it.
The Silent Seraph
Now let's have your inevitable, ignorant debate of that last line.
Please don't use that tone with me. I try to be as respectful as I can in these discussions. I'm not sure if anyone has ever tested my patience quite as much as yourself.
Edit: I found something else from the paper that's definitely worth pointing out, and this time I am going to quote it. In the second study, "religious children very rarely appealed to religion to justify their responses. This is in contrast to the findings from Study 1, where they appealed to religion for both fantastical and religious stories." So, perhaps the children didn't simply regard the stories as true because of their similarity to specific biblical passages, but rather because the children's exposure to religion and all its miracle claims has caused them to be less apt to recognize causal violations as absurd.