Today is Darwin’s birthday, so I thought I’d make one more evolutionary point related to The Believing Brain before I move on.

In that post I worried about facile evolutionary explanations of psychological traits.  At the site Why Evolution is True, Jerry Coyne takes on just such an explanation, based on an article about a forthcoming book, The Republican Brain by Chris Mooney.  The book’s thesis is that Republicans and Democrats have observable differences in brain structure, and these differences have a genetic component.  The author then pushes the theory into the world of evolution, and Coyne (who is a professor of evolutionary biology at the University of Chicago) will have none of it:

Mooney concludes, then, that liberals are a bunch of soft-nosed tree-huggers and bunny lovers, while conservatives are alert and wary, easy to perceive threat.  Where does the evolution come in? Because Mooney suggests that those differences, to the extent that they’re genetic, arose by natural selection.  Not only that, but “liberal” genes are less adaptive than “conservative ones”!:

The big question lying behind all this, of course, is why some people would have stronger and quicker responses than others to that which is perceived as negative and threatening (and disgusting). Or alternatively, why some people — liberals — would be less threat aversive than others. For as the University of Nebraska-Lincoln researchers note: “given the compelling evolutionary logic for organisms to be overly sensitive to aversive stimuli, it may be that those on the political left are more out of step with adaptive behaviors.”

“Compelling evolutionary logic,” of course, is not data: it’s just the perceived ability to make a convincing story. I could easily make a story about why it’s more adaptive for people to smile at bunnies than to frown at Bill Clinton: perhaps that is a byproduct of devotion to one’s children and family, which is also adaptive.  The point, though, is that we have no idea a priori which sort of behavior is or was adaptive in the evolutionary sense of conferring reproductive advantage, and absolutely no data on the reproductive output of liberals versus conservatives.

Science is more powerful than superstition, but you need to think clearly about it, and that often requires experts.  Of course, those alert and wary conservatives don’t have anything good to say nowadays about experts.

To pick up where we left off: The Believing Brain makes the case that beliefs come first, and explanations follow.  We’re hardwired to believe, and this wiring leads to all kinds of false conclusions about the world, because the way our belief system works leaves us open to all kinds of cognitive biases.

Shermer coins a couple of ugly words to embody the basic biological issues underpinning belief: patternicity and agenticity.  Patternicity is our tendency to see patterns — even when they aren’t there.  Agenticity is our tendency to infuse these patterns with meaning, intention, and agency.  (Shermer acknowledges that agenticity is comparable to what Daniel Dennett calls “the intentional stance.”)

Presumably evolution selected for these traits.  You’re better off if you occasionally see a pattern that isn’t there than if you miss patterns and as a result are eaten by a predator hiding in the trees.  You’re more likely to survive if you assume that some inexplicable event was caused by someone with a mind like your own.  And, of course, God is the ultimate pattern, the ultimate agent.  So, primitive man sees lightning in the sky and wonders What’s up with that?  He tries to see a pattern in the even, he assumes that there is intention behind the event.  He decides that some being in the sky is angry about something.  What’s he angry about?  Well, maybe he’s angry at us.  What can we do to calm him down?  Maybe we should sacrifice a goat or something.  Sacrifice a goat, and maybe the lightning stops.  Hey, it works!  Better keep sacrificing goats.  If the lightning comes back — maybe we didn’t sacrifice enough goats.  Or maybe we sacrificed them the wrong way. Or maybe he’s sick of goats — he wants rams or our virgin daughters or something.  Let’s give them a try!

This all seems plausible to me, and Shermer points to lots of neurological research to show what may be going on in the brain to account for this at the physical level (dopamine and whatnot).  But I’m always a little worried when people come up with evolutionary explanations for the way we are — not because I don’t believe in evolution, but because these explanations don’t tend to be testable, so  you can make up an evolutionary case for just about anything and no one can prove you wrong.

This is popular science writing, so Shermer also brings in lots of anecdotes from appearances on TV shows and encounters with conspiracy fanatics and the like.  These are pretty entertaining, although they don’t always advance the plot.  For example, he goes into a lot of detail about why the 9/11 truthers are nuts — good to know, but a little off topic.

The counterbalance to the believing brain is, of course, the scientific method.  Shermer’s discussion of the scientific method is fine, although I started skimming at that point — I already knew most of what he was talking about. Science is our only hope but, as Shermer acknowledges, the problem with the scientific method is that if it leads to conclusions that counter our beliefs, we tend to stick with our beliefs.  It’s easier to believe in miracles than to understand the null hypothesis.