An excellent and insightful reply, Keeper Dan. It is true that once the character has been "initiated" into the fact that there is a horrific, sanity-burning reality out there, it's difficult and indeed implausible for them to continue as if those experiences shouldn't inform their actions and attitudes from that point on. I suppose one could make that willful ignorance an aspect of a character's insanity, admittedly, but let's put that aside for the moment. It's just that I sometimes struggle with the idea of taking an X-Files approach where encounters with the fantastic and horrific simply become de rigueur: "Okay, what am I up against this time?" Admittedly, in Laundry/Delta Green-based games, that's a given -- it's simply built into the structure of the game itself. But I do sometimes think it can skew too much in the direction of Ghostbusters if Keepers and investigators aren't careful -- and that's just not the kind of Call of Cthulhu game I personally like to play. I'm not saying it's wrong or right -- it just comes down to a statement of preference.Keeper Dan wrote: For a shorter campaign, using non-supernatural elements works fine, but I could see it being more tricky in a longer campaign. It's not like the characters un-learn that they faced Deep Ones and a mad sorcerer living in a basement. If I had those experiences and were still able to function, I'd probably start looking for weird stuff behind every shrub. After that innocence is broke, there's no fixing it unless you kill off the characters and bring in new ones.
I love playing with skeptical investigators -- both as a player character and as a Keeper. For me, a large part of the charm of the game (if that makes sense) is watching persons who are thoroughly ensconced in the mundane "realities" of everyday life struggle to come to grips with the fantastic. It reminds me of something I once heard or read by Stephen King to the effect that horror is more "horrific" when it is juxtaposed with things that are thoroughly normal. I don't say i as well as he does, alas. To go back to Dan's point -- that sooner or later an investigator is going to lose his or her "virginity" in this respect -- well, yes, that's absolutely true. But it's also why I like the idea of ultimately letting go of those characters who have been so thoroughly immersed in the Mythos as to make them misfits in everyday society, assuming they live that long, and starting over with the next campaign or sequence of adventures.
Again, sorry for the long and rambling reply. This is just something I find fascinating about the game and I love to hear others' insights about this.