Unwordy Analysis: Can You Identify Authors by Their Punctuation?

Can you identify who wrote a big chunk of text, if you remove all the words and examine only the punctuation. This new study says that in many cases yes, you can:

Pull Out All the Stops: Textual Analysis Via Punctuation Sequences,” Alexandra N.M. Darmon, Marya Bazzi, Sam D. Howison, and Mason Porter, SocArXiv. January 1. 2019. The authors, at the University of Oxford, the University of Warwick, and University of California, Los Angeles, write:

Whether enjoying the lucid prose of a favorite author or slogging through some other writer’s cumbersome, heavy-set prattle (full of parentheses, em-dashes, compound adjectives, and Oxford commas), readers will notice stylistic signatures not only in word choice and grammar, but also in punctuation itself…. In this paper, we examine punctuation sequences in a corpus of literary documents and ask the following questions: Are the properties of such sequences a distinctive feature of their punctuation sequences? Do the punctuation styles of authors evolve over time? Are we on to something interesting in trying to do stylometry without words, or are we full of sound and fury (signifying nothing)? …

Using a large corpus of documents from Project Gutenberg, we observed that simple punctuation-based quantitative features (which account for both frequency and order) can distinguish accurately between the styles of different authors.

Here are further details from the study.

In (a), we show the temporal evolution of all punctuation marks. For clarity, we also separately plot (b) the three punctuation marks with the largest frequencies in the final year of our data set.
Temporal evolution of mean number of words between two consecutive punctuation marks versus author middle years, which we
bin into ten-year periods starting at 1700. This reflects how the punctuation rate in our corpus has changed over time.