Unique names increased in Japan over 40 years: Baby names published in municipality newsletters show a rise in individualism, 1979-2018

•We examined whether Japanese culture became more individualistic by investigating baby names published in municipality newsletters for 40 years between 1979 and 2018.•We collected baby names published in municipality newsletters.•Results showed that over the 40 years, unique names increased in all of the municipalities examined, indicating an increase in uniqueness-seeking and individualism in Japan.•The current research investigated cultural changes for a longer time period and presented further evidence of rising individualism in Japan. We examined whether Japanese culture became more individualistic by investigating baby names published in municipality newsletters for 40 years between 1979 and 2018. Previous research has shown that the rates of unique names increased in Japan between 2004 and 2018, suggesting a rise in uniqueness-seeking and individualism. However, it was unclear whether the trend after the 2000s was found before the 2000s. To discuss cultural changes, it is desirable to examine trends over longer periods of time. Unlike in the U.S., databases of names given to newborns in previous years did not exist in Japan. Thus, we collected baby names published in municipality newsletters. Results showed that over the 40 years, unique names increased in all of the municipalities examined, indicating an increase in uniqueness-seeking and individualism in Japan. The current research investigated cultural changes for a longer time period and presented further evidence of rising individualism in Japan. [Display omitted]