Journal of the Japanese Association for Digital Humanitiesに以下の論文が掲載されました（こちらからダウンロードすることができます）。
- Yuichiro Kobayashi, Misaki Amagasa, & Takafumi Suzuki (2017). Investigating the chronological variation of popular song lyrics through lexical indices. Journal of the Japanese Association for Digital Humanities, 2(1), 90-107.
- Popular songs can be regarded as a fine representation of modern society and culture. In particular, the lyrics of popular songs are the most important aspect for understanding the sense of values and linguistic sensitivity in a given generation and community. The purpose of the present study is to investigate the chronological variation of popular Japanese songs using stylometric techniques. This study draws on the lyrics of 858 songs, which appeared on the Oricon annual top 20 single hit chart between 1976 and 2015. The linguistic features investigated in this study include five different types of lexical indices, namely (a) number of words, (b) parts-of-speech, (c) word types, (d) character types, and (e) vocabulary level. Multiple regression analysis was conducted to explore the chronological change in the frequencies of lexical indices. The results showed that the frequencies of word types and character types dramatically changed before and after 1990. Moreover, the usages of auxiliary verbs as well as lower level vocabulary became more prominent,whereas the frequencies of adjectival nouns and conjunctions decreased. The findings suggest that a turning point in cultural trends corresponds with the historically significant political and economic events, such as the end of the Showa era and the burst of the bubble economy.