I have a new theory about why I do so much better with non-fiction than with fiction. It has to do with the way I read and the relationship between reading and kinds of memory. There has probably been no point in the last decade in which I was reading only one book at a time. At present, I am reading thirteen. It is routine for me to leave a partially completed book for weeks or months, while engaging with something more immediately interesting or urgent.
With non-fiction, every sentence and chapter you read gets integrated into your general schema of knowledge on the topic in question. You can read one chapter on cryptography or ice core sampling or the life of Voltaire and it will henceforth be stored along with related thoughts and memories in a general databank of knowledge. Admittedly, the databank is full of rats that chew their way through ideas long left uncontemplated. The point is that there is a single and relatively well ordered web of knowledge in one’s general library.
Fiction, by contrast, demands the recollection of a lot of specific facts in an organized way. You need to remember the world of that book or story: a world potentially very distinct from the ‘general world’ about which non-fiction knowledge is collected. Remembering characters, world characteristics, relationships, and plot points all calls upon us to treat a fictional universe with a similar kind of importance to the real universe. While this is simple enough when reading a single book at a time, it does not fit very well into a reading pattern based on reading many books in parallel, sometimes abandoning any particular one of them for months at a time.