Jannidis, F., Pielström, S., Schöch, C., Vitt, T.: Improving Burrows’ Delta – An empirical evaluation of text distance measures.Book of Abstracts of the Digital Humanities Conference 2015. UWS (2015).
Since John Burrows first proposed Delta as a new stylometric measure (Burrows 2002), it has become one of the most robust distance measures for authorship attribution (Juola 2006, Stamatatos 2009, Koppel, Schler and Argamon 2009). It has been shown to render very useful results in different text genres (Hoover 2004a) and languages (Eder and Rybicki 2013). Nowadays, Delta is widely used not the least because there is the free stylo package in R (Eder, Kestemont and Rybicki 2013). There have been several proposals to improve Delta (Hoover 2004b, Argamon 2008, Eder, Kestemont and Rybicki 2013, Smith and Aldridge 2011). In the following, we report on a series of experiments to test these proposals using collections of novels in three languages. Our results will show that one of Hoover’s and one of Argamon’s measures show good results, but are outperformed in general by Burrows’ Delta and by Eder’s Delta. The modification of Delta proposed by Smith and Aldridge, on the other hand, shows a remarkable improvement of the results in all languages and has the advantage of providing a stable increase of performance up to a specific point, unlike the other measures which are very sensitive to the amount of most frequent words (mfw) used. These results also allow to discuss some of the theoretical assumptions for the success of these measures, even if we are still far away of providing a “compelling theoretical justification” (Hoover 2005) for their success.
Herrmann, J.B., van Dalen-Oskam, K., Schöch, C.: Revisiting Style, a Key Concept in Literary Studies.Journal of Literary Theory.9,25-52 (2015).
Language and literary studies have studied style for centuries, and even since the advent of ›stylistics‹ as a discipline at the beginning of the twentieth century, definitions of ›style‹ have varied heavily across time, space and fields. Today, with increasingly large collections of literary texts being made available in digital form, computational approaches to literary style are proliferating. New methods from disciplines such as corpus linguistics and computer science are being adopted and adapted in interrelated fields such as computational stylistics and corpus stylistics, and are facilitating new approaches to literary style. The relation between definitions of style in established linguistic or literary stylistics, and definitions of style in computational or corpus stylistics has not, however, been systematically assessed. This contribution aims to respond to the need to redefine style in the light of this new situation and to establish a clearer perception of both the overlap and the boundaries between ›mainstream‹ and ›computational‹ and/or ›empirical‹ literary stylistics. While stylistic studies of non-literary texts are currently flourishing, our contribution deliberately centers on those approaches relevant to ›literary stylistics‹. It concludes by proposing an operational definition of style that we hope can act as a common ground for diverse approaches to literary style, fostering transdisciplinary research. The focus of this contribution is on literary style in linguistics and literary studies (rather than in art history, musicology or fashion), on textual aspects of style (rather than production- or reception-oriented theories of style), and on a descriptive perspective (rather than a prescriptive or didactic one). Even within these limits, however, it appears necessary to build on a broad understanding of the various perspectives on style that have been adopted at different times and in different traditions. For this reason, the contribution first traces the development of the notion of style in three different traditions, those of German, Dutch and French language and literary studies. Despite the numerous links between each other, and between each of them to the British and American traditions, these three traditions each have their proper dynamics, especially with regard to the convergence and/or confrontation between mainstream and computational stylistics. For reasons of space and coherence, the contribution is limited to theoretical developments occurring since 1945. The contribution begins by briefly outlining the range of definitions of style that can be encountered across traditions today: style as revealing a higher-order aesthetic value, as the holistic ›gestalt‹ of single texts, as an expression of the individuality of an author, as an artifact presupposing choice among alternatives, as a deviation from a norm or reference, or as any formal property of a text. The contribution then traces the development of definitions of style in each of the three traditions mentioned, with the aim of giving a concise account of how, in each tradition, definitions of style have evolved over time, with special regard to the way such definitions relate to empirical, quantitative or otherwise computational approaches to style in literary texts. It will become apparent how, in each of the three traditions, foundational texts continue to influence current discussions on literary style, but also how stylistics has continuously reacted to broader developments in cultural and literary theory, and how empirical, quantitative or computational approaches have long existed, usually in parallel to or at the margins of mainstream stylistics. The review will also reflect the lines of discussion around style as a property of literary texts – or of any textual entity in general. The perspective on three stylistic traditions is accompanied by a more systematic perspective. The rationale is to work towards a common ground for literary scholars and linguists when talking about (literary) style, across traditions of stylistics, with respect for established definitions of style, but also in light of the digital paradigm. Here, we first show to what extent, at similar or different moments in time, the three traditions have developed comparable positions on style, and which definitions out of the range of possible definitions have been proposed or promoted by which authors in each of the three traditions. On the basis of this synthesis, we then conclude by proposing an operational definition of style that is an attempt to provide a common ground for both mainstream and computational literary stylistics. This definition is discussed in some detail in order to explain not only what is meant by each term in the definition, but also how it relates to computational analyses of style – and how this definition aims to avoid some of the pitfalls that can be perceived in earlier definitions of style. Our definition, we hope, will be put to use by a new generation of computational, quantitative, and empirical studies of style in literary texts.
