Psych scholars from San Diego State and U Georgia used Google Books to systematically explore the growth of swear-words in published American literature: they conclude that books are getting swearier and that this is a bellwether for a growth in the value of individualism: "Due to the greater valuation of the rights of the individual self, individualistic cultures favor more self-expression in general (Kim & Sherman, 2007) and allow more expression of personal anger in particular (Safdar et al., 2009). Thus, a more individualistic culture should be one with a higher frequency of swear word use."
These data also suggest two more historical points. First, the trend toward the use of swear words in books began before George Carlin's 1972 comedy routine. His work therefore captured and possibly amplified an emerging cultural trend. Second, this massive shift in the use of swear words in books occurred despite the U.S. federal government's efforts to reduce profanity on television. In this case, it seems the government was unable to constrain free expression broadly, such as in books (although they almost certainly have been able to on network TV). We have not examined other media in this research, but it is plausible that the cultural push for individual expression has in part resulted in the boom of less regulated media such as satellite radio and cable television.
In summary, the use of swear words was significantly more common in American books in the late 2000s compared with the early 1950s, increasing in a primarily linear fashion over this time period. The size of this effect, expressed as a d, is massive. This change is consistent with a cultural shift from more collective or communal values to more individualistic, self-expressive values.
,The Seven Words You Can Never Say on Television: Increases in the Use of Swear Words in American Books, 1950-2008 [Jean M. Twenge, Hannah VanLandingham and W. Keith Campbell/SAGE Open]
(via Marginal Revolution)