The same Google user behaves differently in AI Overviews and AI Mode.

I broke down a new clickstream study of 846k US Google sessions from Feb and March 2026. Prior public Google SERP mouse-tracking studies measured dozens of people. This one analyzed tens of thousands.

The pattern: AI Mode is autoplay. AI Overviews is the Netflix browse.

In AI Mode, users accept what they're handed. 88% take the AI's shortlist as-is, 74% pick the top result, and 64% click nothing at all. Closed loop.

In AI Overviews, the same user starts comparing. Cursor coverage hits 83% of the visible page (vs. 66% without an AIO). Stillness rises from 29% to 44%. Back-scrolling makes up nearly half of all scroll activity. The user reads, weighs, scrolls past, then circles back.

AI Mode optimization is a visibility problem at the model layer. AI Overview optimization is a comparison problem on the SERP itself.

Full breakdown in today's Growth Memo.