I went back and read it, and I can see that you are correct, PJ. Excellent explanation, too. Thanks.
The piece is still awkward writing, though, IMO.
Rather than the author writing "...children who had been asked to taste a "new" cereal reported liking the same cereal more if there were a popular character depicted on the box," he should have written, "children who had been asked to taste a "new" cereal reported liking the same cereal more if when there were was a popular character depicted on the box."
Anyway, that's how I would have written it if I were the writer. :-)
-PJ