Wharton’s Leon Musolff explores how default settings shape Google’s dominance — and why exposing users to alternatives could boost competition in search.
Google’s near-total dominance in the search engine market is often assumed to be a result of its superior quality. But what if it’s not just about being the best? A recent study, co-authored by Wharton professor of business economics and public policy Leon Musolff, challenges this assumption. Musolff finds that many users stick with Google simply because they never explore other options — and when they do, some choose to stay with a competitor, like Microsoft’s Bing.
In August last year, a U.S. judge ruled Google illegally maintained its search monopoly by paying companies like Apple to keep it as the default, blocking fair competition. But if policymakers want to create a more level playing field, the results of Musolff’s study, published by the National Bureau of Economic Research, suggest they may need to rethink how default settings and consumer learning shape our online behavior.
Today, Google’s search engine market share remains overwhelmingly dominant, controlling around 90% of the global search market. Last year, the company generated $175 billion from search-based advertising, accounting for more than half of its total $307 billion in revenue. Musolff’s study finds that most people don’t actively choose Google — they simply never switch.
When a browser sets Google as the default search engine, as is often the case, most users stick with it out of habit, or an assumption that the alternatives are worse.
“Most devices and browsers actually come with a default search engine,” said Musolff in an interview with Wharton Business Daily. (Listen to the podcast.) “Even though technically you have the choice, you don’t have what we would call an ‘active choice,’ because you are basically just following the default that was set.”
To test this, Musolff and his co-authors divided participants into different groups. Some were simply asked to choose a search engine, while others were paid $10 to switch to Bing for a short period. The results were telling: Very few Google users (1.1%) voluntarily changed their default when given the choice.
However, when paid to use Bing, 58% switched, and 33% of them stuck with the Microsoft alternative even after the experiment ended. Many said they had either grown used to Bing or found it better than expected. This suggests that one of Google’s biggest advantages isn’t necessarily its quality, but its dominance in the search engine market, as most users never give competitors a real chance.
“What we see in our paper is that what wouldn’t work is just removing this Google default,” said Musolff. “If you just have people make an active choice, Google’s market share goes down by maybe one percentage point. But what really would work is if you somehow found a way to get users to try out alternative search engines.”
Another question in the competition debate is whether Google’s dominance is reinforced by its massive data advantage. Musolff’s study examined how search quality improves when a search engine processes more user interactions. But the results suggest that if Bing had access to Google’s data, its search quality would improve slightly, but not dramatically.
Can Policy Interventions Balance the Search Engine Market?
The study’s findings have major implications for policymakers and antitrust regulators. If Google’s dominance is reinforced by default settings and limited user exposure to alternatives, then competition-focused policies should address these structural barriers.
The most effective intervention might involve changing the default search engine temporarily, followed by a “choice screen,” where users select a search engine when setting up a browser or device. This approach would allow users to experience an alternative before making a final decision.
After all, the study found that when users were forced to use Bing for a short period, some discovered they preferred it and never switched back.
“What we propose in the paper to do on top of that is to say, actually, maybe you want to default people into some search engine that isn’t Google for a couple of weeks, and then have sort of a delayed choice screen,” Musolff said. “That way, they get to experience that other search engine, and then they can actually make an informed choice.”
The study’s findings go beyond search engines, however — they highlight a broader issue in digital markets. Many tech giants benefit not just from superior products but from consumer habits, default settings, and limited exposure to alternatives. Whether it’s social media, online shopping, or digital advertising, dominant platforms often shape user behavior in ways that entrench their power.
For regulators, this means that traditional antitrust tools — such as breaking up large firms or imposing fines — may not be enough. Instead, policies that focus on consumer learning and reducing default-driven advantages could be more effective in promoting competition.
