Darwin's God, an article that ran in the New York Times Magazine (March 4), has stimulated me to think about a number of ideas regarding how evolutionary theory relates to thinking about and acting out the future. See my earlier post and thought stub on evolution, God, and ubiquitous computing. I'm posting a longish section here but it's worth it as I've already had some inquiry on whether I've written anything about this theme yet. Thanks to my colleague Grant Kien for that inquiry!
Here's a selection from Darwin's God:
"Some cognitive scientists think of brain functioning in terms of modules, a series of interconnected machines, each one responsible for a particular mental trick. They do not tend to talk about a God module per se; they usually consider belief in God a consequence of other mental modules.
Religion, in this view, is ''a family of cognitive phenomena that involves the extraordinary use of everyday cognitive processes,'' Atran wrote in ''In Gods We Trust.'' ''Religions do not exist apart from the individual minds that constitute them and the environments that constrain them, any more than biological species and varieties exist independently of the individual organisms that compose them and the environments that conform them.''
At around the time ''In Gods We Trust'' appeared five years ago, a handful of other scientists -- Pascal Boyer, now at Washington University; Justin Barrett, now at Oxford; Paul Bloom at Yale -- were addressing these same questions. In synchrony they were moving toward the byproduct theory.
Darwinians who study physical evolution distinguish between traits that are themselves adaptive, like having blood cells that can transport oxygen, and traits that are byproducts of adaptations, like the redness of blood. There is no survival advantage to blood's being red instead of turquoise; it is just a byproduct of the trait that is adaptive, having blood that contains hemoglobin.
Something similar explains aspects of brain evolution, too, say the byproduct theorists. Which brings us to the idea of the spandrel.
Stephen Jay Gould, the famed evolutionary biologist at Harvard who died in 2002, and his colleague Richard Lewontin proposed ''spandrel'' to describe a trait that has no adaptive value of its own. They borrowed the term from architecture, where it originally referred to the V-shaped structure formed between two rounded arches. The structure is not there for any purpose; it is there because that is what happens when arches align.
In architecture, a spandrel can be neutral or it can be made functional. Building a staircase, for instance, creates a space underneath that is innocuous, just a blank sort of triangle. But if you put a closet there, the under-stairs space takes on a function, unrelated to the staircase's but useful nonetheless. Either way, functional or nonfunctional, the space under the stairs is a spandrel, an unintended byproduct.
''Natural selection made the human brain big,'' Gould wrote, ''but most of our mental properties and potentials may be spandrels -- that is, nonadaptive side consequences of building a device with such structural complexity.''
The possibility that God could be a spandrel offered Atran a new way of understanding the evolution of religion. But a spandrel of what, exactly?
Hardships of early human life favored the evolution of certain cognitive tools, among them the ability to infer the presence of organisms that might do harm, to come up with causal narratives for natural events and to recognize that other people have minds of their own with their own beliefs, desires and intentions. Psychologists call these tools, respectively, agent detection, causal reasoning and theory of mind.
Agent detection evolved because assuming the presence of an agent -- which is jargon for any creature with volitional, independent behavior -- is more adaptive than assuming its absence. If you are a caveman on the savannah, you are better off presuming that the motion you detect out of the corner of your eye is an agent and something to run from, even if you are wrong. If it turns out to have been just the rustling of leaves, you are still alive; if what you took to be leaves rustling was really a hyena about to pounce, you are dead.
A classic experiment from the 1940s by the psychologists Fritz Heider and Marianne Simmel suggested that imputing agency is so automatic that people may do it even for geometric shapes. For the experiment, subjects watched a film of triangles and circles moving around. When asked what they had been watching, the subjects used words like ''chase'' and ''capture.'' They did not just see the random movement of shapes on a screen; they saw pursuit, planning, escape.
So if there is motion just out of our line of sight, we presume it is caused by an agent, an animal or person with the ability to move independently. This usually operates in one direction only; lots of people mistake a rock for a bear, but almost no one mistakes a bear for a rock.
What does this mean for belief in the supernatural? It means our brains are primed for it, ready to presume the presence of agents even when such presence confounds logic. ''The most central concepts in religions are related to agents,'' Justin Barrett, a psychologist, wrote in his 2004 summary of the byproduct theory, ''Why Would Anyone Believe in God?'' Religious agents are often supernatural, he wrote, ''people with superpowers, statues that can answer requests or disembodied minds that can act on us and the world.''"