I’ve spent many a night huddled in my rocking chair with a murder mystery held steady under the lamp. Why did I keep reading? It might have something to do with the Zeigarnik Effect, which is defined thusly: The tendency for people to remember unfinished or interrupted tasks better than completed ones.
In writing, this translates to leaving questions open—introducing problems, tensions, or mysteries that are not immediately resolved. Sound familiar? “I don’t care if I wake up late tomorrow, I’ve got to find out how the corpse came back to life and performed in a play!” Whether it’s a missing motive, a strange detail, or a contradiction that doesn’t make sense yet, the reader stays engaged because their mind is actively trying to complete the pattern.
The Zeigarnik Effect fits mystery fiction (especially impossible crime stories) like a lock fits its key. These narratives are built out of deliberate incompletion: contradictions that shouldn’t exist, timelines that refuse to align, rooms that seal themselves against reason. Each of these elements creates an open mental loop the reader cannot comfortably ignore. The impossible crime sharpens this even further because the central question isn’t merely who committed the murder, but how reality itself seems to have been violated. That kind of paradox lodges in the mind and stays active. Every clue, every witness statement, every physical detail becomes part of an unresolved system the reader is compelled to reconcile. In that sense, the writer is engineering a series of cognitive tensions that the reader feels an almost physical need to resolve.
Of course, not all storytelling thrives on this kind of omission.
When I was thirteen, I read Hills Like White Elephants in my English class. I was far too young to appreciate Hemingway and I was far too young to understand what the story was about. At the end of the class, our teacher informed us. This story is probably the best example of Hemingway’s Iceberg Theory. It’s the radical notion that a story should present only the surface details, while the deeper meaning remains unstated beneath the text.
This approach is considered a strength because it creates depth and subtlety. By leaving things unsaid, the writer invites the reader to infer meaning, read between the lines, and engage more actively with the story. (Contrast this with the game of gathering clues in a murder mystery to solve the case.) It can make prose feel more natural, restrained, and powerful, since the impact comes from implication rather than explicit explanation.
Iceberg Theory runs counter to the core promise of murder mysteries. Hemingway’s approach relies on omission, and what is left unsaid carries the weight. But a fair-play mystery, particularly an impossible crime, depends on the opposite contract: nothing essential can remain submerged. The reader expects not just an answer, but a complete accounting—every clue placed, every contradiction resolved, every mechanism laid bare. This is why the seemingly artificial convention of gathering all suspects in a room persists; it satisfies a structural need for total clarity. In mystery fiction, ambiguity is a breach of trust. Where the iceberg invites the reader to sit with uncertainty, the mystery demands that uncertainty be methodically dismantled.
In a way, mysteries do use the iceberg; they just refuse to leave it submerged. For most of the story, things are hidden, implied, half-glimpsed. But unlike Hemingway, we don’t leave them there. By the end, the whole thing has to rise to the surface. That’s a strength and a limitation of the form.
James Scott Byrnside 