So it was with Joyride. It's about a man who witnesses a couple commit murder and decides that they would be the perfect people to help him with a little spree...uh, project of his own. It's hardcore, no doubt, and every bit as gruesome as it sounds. And at the end of it, I could only shake my head and think: great writing, but where the hell's this guy's head at?
Which could be said (and has - I know this for a fact) about anyone writing horror, right?
But this actually isn't a book review, and it certainly isn't an attempt to justify or judge why any writer writes what they do. This is more about the ideas themselves. Stephen King and others have gone on at length about that most oft-asked question by non-writers: "Where do you get your ideas?"
As if we knew.
But in Ketchum's case, there is a sense of how the process works for one writer. In the afterward to Joyride, Ketchum explains that while he doesn't outline his works, he essentially "scrapbooks" his ideas, that is, he will collect disparate ideas with no obvious connection until - bam! - the ideas coalesce into something that becomes a book. This, I think (and this is entirely my own humble opinion, of course) may work for him because of the "ripped from the headlines" subjects. Ketchum readily admits that seed for Joyride came from another story by Emil Zola, called La Bete Humaine, where a character standing in a railway yard witnesses two people commit a murder. The antagonist in Ketchum's work is pieced together from what is known about several serial killers, and some of the other characters are fashioned after some of Ketchum's own experiences. Apparently, this is how Ketchum comes up with most of his ideas.
I found this utterly fascinating, because it is both like and unlike the way my ideas come. For me, ideas usually come as a single image or line of dialogue (although I have had some ideas come from stories I've heard, real or fiction) and my mind works at it like an anthropologist lovingly piecing together ancient artifacts until the story of the people who left them is told. For instance, one short story of mine, "Mama Sweet," came to me while I was washing dishes one day. In my mind, I saw a little girl walking alongside a fence. In one hand, she held a teddy bear, and the light was weak, unnatural - I remember that particularly - and I thought to myself, what is this girl doing out by herself like that? The answer came slowly, a bit at a time, not as if I was creating a story, but more as if I were both zooming outward and focusing with greater and greater clarity on a series of events until the truth was revealed.
See why writers rarely have a good answer to "where do you come up with your ideas?" The answer to that question can be as slippery and difficult to define as why someone "chooses" to write in a particular genre in the first place.
The ideas come from wherever they come from, and the artist is blessed. And we work in whatever medium or genre we work in because to do otherwise is unthinkable.
Sorry, but it's all I got.
You want concrete answers, join a math club.