Among these assumptions are:
1. Every trait is an adaptation, i.e. has an evolutionary function
2. Evolutionary adaptations are optimally designed
3. Natural selection is unconstrained
The characteristics of the evolutionary process are quite different, however:
1. Traits of an organism can be the outcome of a variety of processes, not just of direct natural selection. They can be by-products of selected traits; the results of short-term fluctuations in biological and/or environmental context; the outcome of robust generative developmental processes; or the result of developmental noise.
2. Evolutionary outcomes are not necessarily optimal in any sense, because evolution lacks freedom and foresight. Its "solutions" are never "designed" from scratch. It has to work with and build on what is available, which often is highly limited. Evolution is a tinkerer, not a designer. We are much better served by thinking about evolution in terms of the tortuous bizarreness of a Rube Goldberg device than the streamlined perfection of modern automobile design. The peculiar way the vertebrate retina is constructed is a case in point.
3. The variation that fuels evolution is constrained by the availability of developmental resources, which in turn depends on the history of the organism and its lineage. Every type of organism comes equipped with a morphological structure that severely restricts the range of possible directions in which further evolution can proceed. It is also embedded in a physical (and social) environment which can be substantially of its own making and likewise channels its future evolution.
4. Evolution is largely a historical and contingent process. We cannot infer the status of a trait as evolved by natural selection from general considerations ("This trait is so complex, it must be an evolutionary adaptation"; or "Detecting cheaters was certainly important in our ancestors' social environment, so it's likely that our present ability to do so is an evolutionary adaptation"). Rather, showing that a trait is an evolutionary adaptation requires adducing substantial historical evidence, most of which is not available for mental traits that do not fossilize.
His main point seemed to be, since he came back to it frequently, that evolutionary traits are often inelegant and not optimal -- a kluge. Further, not all adaptations necessarily have a function, contrary to widely held beliefs among the scientifically-minded public.
Well, that puts a wrench in John Stewart's Evolution's Arrow theory. Funny that they both spoke in the same session. It was a nice balance in approaches from two well-known and respected psychologists.
But Gamma is not alone in his beliefs.
In his new book, Kluge: The Haphazard Construction of the Human Mind, research psychologist Gary Marcus argues that the human brain is a "Kluge," a term popularized by computer pioneer Jackson Granholm, "an ill-assorted collection of poorly matching parts, forming a distressing whole."
He contends that evolution has produced a complex, but overloaded, neurological system that utilizes "contextual memory"- we retrieve material out of our memories by using context or clues that hint at what we are looking for. Thus, the system is built for speed rather than reliability, and is better at the quick retrieval of general information rather than specific details.
"In the best-case situation, this process works well: the particular memory we need just 'pops' into our minds, automatically and effortlessly," Marcus, a professor in NYU's Department of Psychology, writes in the New York Times Magazine. "The catch, however, is that our memories can easily get confused, especially when a given set of cues points to more than one memory. What we can remember at any given moment also depends heavily on the accidents of which bits of mental flotsam and jetsam happen to be mentally active at that instant. Our mood, our environment - even our posture - can all influence our delicate memories."
This is from Publisher's Weekly review of Kluge:
Why are we subject to irrational beliefs, inaccurate memories, even war? We can thank evolution, Marcus says, which can only tinker with structures that already exist, rather than create new ones: 'Natural selection... tends to favor genes that have immediate advantages' rather than long-term value. Marcus (The Birth of the Mind), director of NYU's Infant Language Learning Center, refers to this as 'kluge,' a term engineers use to refer to a clumsily designed solution to a problem. Thus, memory developed in our prehominid ancestry to respond with immediacy, rather than accuracy; one result is erroneous eyewitness testimony in courtrooms. In describing the results of studies of human perception, cognition and beliefs, Marcus encapsulates how the mind is 'contaminated by emotions, moods, desires, goals, and simple self-interest....' The mind's fragility, he says, is demonstrated by mental illness, which seems to have no adaptive purpose. In a concluding chapter, Marcus offers a baker's dozen of suggestions for getting around the brain's flaws and achieving 'true wisdom.' While some are self-evident, others could be helpful, such as 'Whenever possible, consider alternate hypotheses' and 'Don't just set goals. Make contingency plans.' Using evolutionary psychology, Marcus educates the reader about mental flaws in a succinct, often enjoyable way.
You can also read a photocopy of P.Z. Myers' review for Seed.
One of the most obvious areas in the human brain that fits the kluge idea is memory. Rather than the efficiently organized memory storage systems of computers, our brains seemingly store memories at random, without any idea where they are, and relying on sense triggers or random associations quite often to access older memories.
Marcus wrote about this recently -- Total Recall -- in the New York Times:
The dubious dynamics of memory leave us vulnerable to the predations of spin doctors (because a phrase like “death tax” automatically brings to mind a different set of associations than “estate tax”), the pitfalls of stereotyping (in which easily accessible memories wash out less common counterexamples) and what the psychologist Timothy Wilson calls “mental contamination.” To the extent that we frequently can’t separate relevant information from irrelevant information, memory is often the culprit.All this becomes even more poignant when you compare our memories to those of the average laptop. Whereas it takes the average human child weeks or even months or years to memorize something as simple as a multiplication table, any modern computer can memorize any table in an instant — and never forget it. Why can’t we do the same?
Much of the difference lies in the basic organization of memory. Computers organize everything they store according to physical or logical locations, with each bit stored in a specific place according to some sort of master map, but we have no idea where anything in our brains is stored. We retrieve information not by knowing where it is but by using cues or clues that hint at what we are looking for.
In the best-case situation, this process works well: the particular memory we need just “pops” into our minds, automatically and effortlessly. The catch, however, is that our memories can easily get confused, especially when a given set of cues points to more than one memory. What we remember at any given moment depends heavily on the accidents of which bits of mental flotsam and jetsam happen to be active at that instant. Our mood, our environment, even our posture can all influence our delicate memories. To take but one example, studies suggest that if you learn a word while you happen to be slouching, you’ll be better able to remember that word at a later time if you are slouching than if you happen to be standing upright.
And it’s not just humans. Cue-driven memory with all its idiosyncrasies has been found in just about every creature ever studied, from snails to flies, spiders, rats and monkeys. As a product of evolution, it is what engineers might call a kluge, a system that is clumsy and inelegant but a lot better than nothing.
Read the whole article.
Marcus had another interesting article at Huffington Post recently: Does Brain Imaging Make You Dumb?
This is worth the few minutes to read it -- especially if you have ever looked at fMRI images of the brain and thought you understood the brain better.
Here is an excerpt from the book, posted at the CTV site:
Remnants of History
"It has been said that man is a rational animal. All my life I have been searching for evidence which could support this."
-- Bertrand Russell
Are human beings "noble in reason" and "infinite in faculty" as William Shakespeare famously wrote? Perfect, "in God's image," as some biblical scholars have asserted? Hardly.
If mankind were the product of some intelligent, compassionate designer, our thoughts would be rational, our logic impeccable. Our memory would be robust, our recollections reliable. Our sentences would be crisp, our words precise, our languages systematic and regular, not besodden with irregular verbs (sing-sang, ring-rang, yet bring-brought) and other peculiar inconsistencies. As the language maven Richard Lederer has noted, there would be ham in hamburger, egg in eggplant. English speakers would park in parkways and drive on driveways, and not the other way around.
At the same time, we humans are the only species smart enough to systematically plan for the future -- yet dumb enough to ditch our most carefully made plans in favor of short-term gratification. ("Did I say I was on a diet? Mmm, but three-layer chocolate mousse is my favorite... MaybeI'll start my diet tomorrow.") We happily drive across town to save $25 on a $100 microwave but refuse to drive the same distance to save exactly the same $25 on a $1,000 flat-screen TV.
We can barely tell the difference between a valid syllogism, such as All men are mortal, Socrates is a man, therefore Socrates is mortal, and a fallacious counterpart, such as All living things need water, roses need water, therefore roses are living things (which seems fine until you substitute car batteries for roses). If I tell you that "Every sailor loves a girl," you have no idea whether I mean one girl in particular (say, Betty Sue) or whether I'm really saying "to each his own." And don't even get me started on eyewitness testimony, which is based on the absurd premise that we humans can accurately remember the details of a briefly witnessed accident or crime, years after the fact, when the average person is hard pressed to keep a list of a dozen words straight for half an hour.
I don't mean to suggest that the "design" of the human mind is a total train wreck, but if I were a politician, I'm pretty sure the way I'd put it is "mistakes were made." The goal of this book is to explain what mistakes were made -- and why.
There's more, so check it out.
You can also watch Marcus talk with Carl Zimmer at Bloggingheads.tv and a shorter TV appearance on CTV.
I don't really have any objections to his arguments, at least from what I have read and heard. It makes sense biologically.
However, the cool thing is that we are so efficient despite this random assortment of sub-routines in our brains. Even more, it's cool that we are conscious.
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