[neilc]

I'd be curious to know if there's any empirical evidence for this -- that's precisely the sort of plausible claim that might easily not be supported by the evidence.

[mechanical_fish]

I'm sure there's empirical evidence somewhere that can either confirm or deny this hypothesis, exactly as stated. But it's so valuable that Google isn't likely to give you a peek at it for free.

Maybe some other market research firm will sell you related information. Or you could buy a few Google ads and see, I guess. Watch out for sample bias.