Cultural Shift or Linguistic Drift? Comparing Two Computational Measures of Semantic Change

Proceedings of the 2016 Conference on Empirical Methods in Natural Language Processing, pages 2116–2121, Austin, Texas, November 1-5, 2016. c⃝2016 Association for Computational Linguistics Cultural Shift or Linguistic Drift? Comparing Two Computational Measures of Semantic Change William L. Hamilton, Jure Leskovec, Dan Jurafsky Department of Computer Science, Stanford University, Stanford CA, 94305 wleif,jure,jurafsky@stanford.edu Abstract Words shift in meaning for many reasons, including cultural factors like new technolo- gies and regular linguistic processes like sub- jectification. Understanding the evolution of language and culture requires disentangling these underlying causes. Here we show how two different distributional measures can be used to detect two different types of seman- tic change. The first measure, which has been used in many previous works, analyzes global shifts in a word’s distributional semantics; it is sensitive to changes due to regular pro- cesses of linguistic drift, such as the semantic generalization of promise (“I promise.”→“It promised to be exciting.”). The second mea- sure, which we develop here, focuses on local changes to a word’s nearest semantic neigh- bors; it is more sensitive to cultural shifts, such as the change in the meaning of cell (“prison cell” → “cell phone”). Comparing measure- ments made by these two methods allows re- searchers to determine whether changes are more cultural or linguistic in nature, a distinc- tion that is essential for work in the digital hu- manities and historical linguistics. 1 Introduction Distributional methods of embedding words in vec- tor spaces according to their co-occurrence statis- tics are a promising new tool for diachronic seman- tics (Gulordava and Baroni, 2011; Jatowt and Duh, 2014; Kulkarni et al., 2014; Xu and Kemp, 2015; Hamilton et al., 2016). Previous work, however, does not consider the underlying causes of seman- tic change or how to distentangle different types of change. We show how two computational measures can be used to distinguish between semantic changes caused by cultural shifts (e.g., technological ad- vancements) and those caused by more regular pro- cesses of semantic change (e.g., grammaticalization or subjectification). This distinction is essential for research on linguistic and cultural evolution. Detect- ing cultural shifts in language use is crucial to com- putational studies of history and other digital hu- manities projects. By contrast, for advancing histor- ical linguistics, cultural shifts amount to noise and only the more regular shifts matter. Our work builds on two intuitions: that dis- tributional models can highlight syntagmatic ver- sus paradigmatic relations with neighboring words (Schutze and Pedersen, 1993) and that nouns are more likely to undergo changes due to irregular cul- tural shifts while verbs more readily participate in regular processes of semantic change (Gentner and France, 1988; Traugott and Dasher, 2001). We use this noun vs. verb mapping as a proxy to compare our two measures’ sensitivities to cultural vs. lin- guistic shifts. Sensitivity to nominal shifts indi- cates a propensity to capture irregular cultural shifts in language, such as those due to technological ad- vancements (Traugott and Dasher, 2001). Sensitiv- ity to shifts in verbs (and other …

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