One of the things I wanted to do when I grew up was to catalogue fairy tales. I read a few collections of fairy tales from various countries and noticed that there were notable similarities between folk tales from completely unrelated countries. I decided I would hunt down these similarities, compare them, and find out why this was.
When I grew up, I found this had already been done. Well, fairy tales had been catalogued- centuries ago. There were universally acknowledged and referenced 'types', which you can refer to by number if you know the catalogue well. This was fairly discouraging. I guess I should have seen it coming, what with the collections of comparative folktales and all, but you always hope. They'd even tried to figure out why. This is where Jung's idea of the collective unconscious theory comes in. As far as I understand it, the theory states that human experience is to some extent innately shared between all humanity, without needing to be learned, and this knowledge encompasses a large portion of mythology, and perhaps language to an extent.
I kind of like that theory, it has an implication for the shared humanity of all people, and that everyone has something in common deep down. But I think it's largely discredited, maybe there's some correlation between the preference for nurture over nature in the nature vs. nurture debate. Which has now swung back, at least a bit. Also modern science and psychology doesn't sit well with it. So maybe I will have to give up on it. Another theory involves migration.
Long story short, I find fairy tale comparisons fascinating. So many variations, so similarity. Joseph Campbell tried to condense the comparison even further, by theorising that most tales share one basic structure, involving hero going on a journey. This was famously used by George Lucas as the basis for Star Wars. It's interesting that where fairy tale similarities are seen as a sign of shared humanity, works of popular culture which share similar themes are often seen as derivative. That seems somewhat unfair. So I'm glad to see that they have now catalogued tropes in popular culture in a handy online location- TVTropes. Although, I will warn you that XKCD has classified that site as addictive, so view at your own peril.
I wonder how much overlap there is between folk and fairy tale tropes and popular culture tropes?