What they did
Pew Research Center recruited 900 US adults from an online probability panel who let an app record their browsing. It logged every Google search and click during March 2025, then coded which result pages carried an AI summary.
What they found
Around 18% of searches produced an AI summary. When one showed, people clicked a normal search result on 8% of visits, against 15% when no summary appeared. Only 1% of visits included a click on a source cited inside the summary itself. Sessions ended on 26% of pages with a summary versus 16% without.
How much weight to give it
This is one of the few studies watching real logged behaviour rather than modelled clickstream estimates. The panel is probability-based and the query count is large, so the click gap is credible.
What it doesn't prove
It covers a single month and US users only. Google disputed the findings. AI Overviews were still young in March 2025, so the numbers will have moved since.