Masaru is interested in comparative politics, computational social science, Japanese politics, and American politics.
Using different methods, he has studied interrelated topics in different countries and time periods, theoretically and empirically.
In particular, he focuses on American democracy and affective/ideological polarisation.
Additionally, he has studied the impact of the rise of populism on democratic politics in the US, Japan, and other countries.
He also works on the impact of misinformation/ disinformation (e.g. conspiracy theories) on democratic politics, such as in Japan and the US.