That's the same source I found for the quotation when I hit up the search engines, but I was rather hoping for a naturalist of some description to back up the theory. I don't see that you could be confident of that explanation without some amount of field work. Who put in the eye-hours to develop and confirm this hypothesis?
Edit: I mean, if Eb the author did, that's fine, but he doesn't even mention growing up in the country.
O, btw, I grew up in the country. Spent several years on the sheep farm. Interestingly, the herd dogs use the same "signal" mechanism to move sheep. Rather than run around and bark, they get in "predator" pose and the sheep move accordingly.
Interesting to watch low-power energy, i.e. "signals", accomplish work.
Sweet, there's another Bloggingheads episode with Eliezer.
Bloggingheads: Robert Wright and Eliezer Yudkowsky: Science Saturday: Purposes and Futures