Edward Harris's contention that religion--the capacity for unsubstantiated believe--evolved genetically leads to several interesting notions. As I've mentioned elsewhere (The Sacred Pool afterword) the willing suspension of disbelief that fiction writers struggle to maintain and the struggle of the Faithful with inevitable skepticism ("Lord, I believe. Help thou my unbelief. ") are, when viewed as a defining human trait, one and the same.
This amazing ability to accept, for the length time it takes to read a novel, that witches' spells really work, or that spaceships can travel faster than light, stems from the same adaptation that allows us to accept virgin birth, a convoluted, non-intuitive concept of Trinity, and Mohammed's overnight journey to Jerusalem and back on a magical winged horse.
Obviously, that capacity once had adaptive advantage. At some time between 70,000 and 35,000 B.C., when worldwide glaciation exerted its greatest stress upon the human race, and at the very time when survival depended upon our ancestors graduating from generalized primate troop to the more organized and specialized human tribe, the ability to adopt a common belief system and to adhere to it rigorously, even obsessively, was a significant survival adaptation.
But like the island-dwelling elephants (a kind of mini-mammoth, if I recall correctly) for whom great size became a liability, the human proclivity to hold irrational beliefs in the face of clearly established fact has become maladaptive as it now acts to suppress not only genuine knowledge (as in Wahabist Islamic "schools" and Christian fundamentalist ones) but to restrict enlightened progress like the emancipation of women, and above all to support and encourage Jihad, largely the product of another once-adaptive human behavior that has now become self-destructive: feud and revenge.
And of course people who are conditioned by Wahabist teachers or Christian home schooling parents to believe literally in magical nighttime journeys, in reanimated corpses (whether of a religious leader or a Halloween nightmare is no qualitative distinction), or of a unique creation sometime around 6000 B.C., become by that training equally susceptible to accept any other promulgation by Imam Achmed or Jim Jones, and strap on a C 4-packed vest or toss down a cup of doctored Kool-Aid. Clearly, these illustrate the evolutionary dead-end that Harris's adaptation has reached. And of course such "Conservatives" are not the only ones affected by the malaise... Doesn't the name Harry Reid come to mind?