As part of his research, Guy Aridor of Columbia University blocked participants’ access to YouTube and Instagram.
On February 28, 2022, Aridor joined Stanford Digital Economy Lab Director Erik Brynjolfsson for “Drivers of Digital Attention: Evidence from a Social Media Experiment.”
I study demand for social media services by conducting an experiment where I comprehensively monitor how participants spend time on digital services. I shut off access to Instagram or YouTube on their mobile phones and investigate how participants substitute their time allocations during and after the restrictions. During the restriction period, I observe substitution towards a wide range of alternatives including across product categories and off digital devices and relate these findings to market definition in attention markets. Participants with the Instagram restriction had their average daily Instagram usage decline after the restrictions are lifted. Participants with the YouTube restriction spent more time on applications installed during the restriction period both during and after the restriction period.
Motivated by these results, I estimate a discrete choice model of time usage with inertia and find that inertia explains a large portion of the usage on these applications. I apply the estimates to conduct merger evaluation between prominent social media applications using an Upward Pricing Pressure Test for attention markets. I find that inertia plays an important role in justifying blocking mergers between the largest and smallest applications, indicating that digital addiction issues are important from an antitrust perspective. Overall, my results highlight the usefulness of product unavailability experiments in analysis of mergers between digital goods.
Guy Aridor is an Economics PhD candidate at Columbia University. He holds a BA in Economics, Computer Science, and Pure/Applied Mathematics from Boston University. His research studies competition and regulatory issues in digital markets, with a particular focus on the economic aspects of consumer data collection and dissemination. He has worked on projects studying social media, privacy regulations, recommendation systems, and online product experimentation. His work uses methods from empirical industrial organization, applied microeconomic theory, and field experiments to study substantive economic issues in this space.
