The role of human interaction in innovation: evidence from the 1918 influenza pandemic in Japan

This study empirically investigates human interaction’s role in innovation by exploiting the 1918 influenza pandemic in Japan from 1918 to 1921, which prohibitively increased the cost of interactions between inventors. Using unique patent bibliographic data for this period, we estimate the pandemic’s impact on innovation in technologies requiring intensive human interaction for invention. Specifically, we define patent technology classes with large fractions of collaborative patents before the pandemic as collaboration-intensive technology, which requires intensive human interaction for invention. Thereafter, we estimate the pandemic’s impact on the invention of collaboration-intensive technology using the difference-in-differences (DID) approach. The estimation results reveal that during the pandemic, patent applications for collaboration-intensive technology significantly decreased compared to the control group and did not fully recover, even after the pandemic ended. Additionally, we find that the negative impact is driven by a decrease in new entries into patent applications, that is, patent applications by inventors applying for patents for the first time. These results suggest that a decrease in interactions with colleagues and seniors in the preliminary stages of inventors’ careers reduces opportunities to nurture new inventors.