The book actually does address this. ROT13 to avoid spoilers:
Vg vf fgebatyl fhttrfgrq gung gur inzcverf bs gur abiry ynpx pbafpvbhfarff, juvpu tnir gurz n fvtavsvpnag nqinagntr bire 'onfryvar' uhznaf gung gurl uhagrq.
Still, I remain unconvinced of the author's depictions of a lack of consciousness. The problem is the "philosophical zombie". It looks and acts, to all accounts, like a normal human, but has no internal experience. Since I can't even prove anybody else has experience (despite acting a lot like me), what's the basis for different behavior just because an organism lacks consciousness?
I found it intriguing but unlikely, based on evolutionary fitness.
We know that perceptual awareness has some connection to biology (sleep, seizures, drugs, etc), so to the extent that consciousness requires energy, it has to justify its caloric expenditure.
However, it strongly requires that consciousness be not detrimental (at least not overall), because otherwise, evolution probably would have weeded it out.
The novel Blindsight kind of suggests that humans are a local evolutionary maxima, that we achieved mastery of our planet due to our other talents, despite being burdened with consciousness. But again, this runs afoul of evolutionary fitness. Even if animals lacking consciousness couldn't surmount our other abilities, if a mutant human arose without consciousness, presumably it would have an advantage over other humans, and its genes would spread throughout the populace.
The book is really interesting, but having studied this for 7 years of my life, there's no way the author is correct. It's much more likely that other animals experience conscious awareness too. We don't know for sure, and we don't know where to draw the line (fish, insects, aplysia, bacteria?), but it seems reasonable to believe higher mammals have awareness (which is distinct from language, tool use, self-reflection, Theory of Mind, etc).