It's an author's words, rather than their punctuation, that we think of as defining their style. But as Adam J. Calhoun found out this week, the periods, colons, semicolons, and commas a writer uses can have just as much impact on their output as their choice of language. In a Medium post, Calhoun stripped the words out of some of his favorite books, leaving them as streams of pure punctuation. The results showed a stark contrast between the way authors use the tools in their texts, with some exhibiting a preference for dialogue, some using commas and semicolons to construct breathless sentences, and some making almost exclusive use of the most common marks to tell their stories.

The biggest difference, Calhoun found, was between Cormac McCarthy's Blood Meridian, and William Faulkner's Absalom, Absalom! McCarthy, famous for his short sentences and unpunctuated conversations, relies almost entire on periods, commas, and a handful of question marks in his book. Faulkner, on the other hand, employs semicolons, apostrophes, and thousands of commas in his work, creating lengthy run-on passages nested inside complex arrangements of punctuation. Blood Meridian's sentences use half the words on average of Faulkner's book, McCarthy clearly preferring to break a thought into a few utterances where Faulkner happily strings them together.

This reliance on commas is apparently hallmark of older fiction: Mary Shelley's Frankenstein, Jane Austen's Pride and Prejudice, and Charles Dickens' Great Expectations all lean more heavily on the comma than the period to build descriptive sentences. But there are surprises in Calhoun's findings, too. James Joyce's Ulysses, well known for its complex modernist prose, uses surprisingly standard punctuation: lots of commas and just a few colons to frame text that's largely broken up by regular old periods.

Calhoun has also transferred the data he harvested from the books into heatmaps, glowing red where periods, question marks, and exclamation marks were used, green for commas and quotation marks, and blue for colons and semicolons. Faulkner's Absalom, Absalom! is one of the few stories with shades of green to shine through; as befitting the gory subject matter, McCarthy's Blood Meridian heatmap is almost entirely red.