LIWC-ing at a Century of Introductory College Textbooks: Have the Sentiments Changed?

In this study, we analyzed the language from 66 Introduction to Psychology college textbooks published over the last eleven decades. In our analysis, however, we put aside the usual tools employed in text and sentiment analysis and used instead the Linguistic Inquiry Word Count (LIWC), an often-overlooked tool that originated in Social Psychology. Our analysis across decades revealed significant shifts in almost all summary variables. Authors wrote with gradually increasing authority and less tentatively over the decades. But at the same time, authors wrote in a more guarded and less emotional manner from earlier writings to the present.