Is it possible some became interested and learned more after their experience?
Discussion
Yes. But could also just be the case that they are stitching together experienced from their knowledge about the subject.
Almost certainly happens. It's a common (similar) issue with healthcare and psychology students as well. But there are also instances where people find things more often specifically because they are looking and haven't written it off or developed tunnel vision (an opposite problem in healthcare differentials). I don't know how to strike a balance with these things other than to have an open mind while leaning heavily on evidence, as you mentioned.