Is human consciousness a trick to ensure survival?

Commenter ST quotes psychologist Nicholas Humphrey at Edge, saying:

I believe that human consciousness is a conjuring trick, designed to fool us into thinking we are in the presence of an inexplicable mystery. Who is the conjuror and why is s/he doing it? The conjuror is natural selection, and the purpose has been to bolster human self-confidence and self-importance—so as to increase the value we each place on our own and others' lives.

Now, like the commenter, I am pretty skeptical when I read stuff like that, and there is an amazing amount of it out there right now.

One aspect of the question of consciousness that is worth commenting on is the assumption that the advent of consciousness improved human survival chances. Of course it did in the long run; otherwise we would not be as numerous as we are. But it didn't do so in the short run, or not noticeably. The short run matters because Darwinian evolution, by its very nature, is not goal-directed, so the Darwinist must show that consciousness also aids survival in the short run. And that is far from clear.

To see what I mean, read J. G. Frazer's The Golden Bough, an account of the earliest known religions. When humans became conscious of such matters as future risk and inevitable death, they seem to have developed manage them. Some of these beliefs and rituals (washing, for example) may have been useful, but others were time sinks (menstrual taboos, ancestor worship, etc.) Many practices, such as human sacrifice and the execution of violators of a taboo, etc., surely decreased the human population, as would any form of religious or ideological warfare. All these net population decreases are direct outcomes of human consciousness that would not occur in a non-conscious species.

Once humans became conscious, there was no going back, to be sure, but there was certainly a long period when it was only intermittently "useful" in the Darwinian sense - which suggests in turn that consciousness did not develop in a Darwinian way.