[n1c00o]

I assume they do use your search history for some purposes. For instance I have been enrolled inside the Foo Bar challenge from Google, and from my deductions it is thanks to my search history (mainly programming-related). The Foo Bar challenge is a suite of tricky programming questions and in the end, some of the winners of the challenge receive a message from Google's recruiting team (as I did) where it can lead to a job at Google.

This is only my deductions from my experiences with Foo Bar, it might only be in that case, I am not exactly sure, but you should assume they do.

[KomoD]

That's not a person checking it.

[n1c00o]

It still means they are, therefore it is not impossible for an automation to detect “red flags” and warning the recruiter for manual verification or anything.