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Evolution Did Not Snap the Brain Together like LEGOS

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Human cognition is more than a legacy of our Paleolithic past

Evolutionary psychology has typically tried to identify the piece parts of human cognition shaped by the rigors of natural selection. New questions have arisen in this contentious discipline about what exactly is on that parts list—or whether the list itself really exists.

One of the foremost debating points centers on whether the brain consists of a series of Lego-like modules, each one produced from evolutionary adaptations that resulted in mental tools for things like going after Mastodons, forming clans and communicating the daily incidentals related to food, shelter and mating.  Another way to think about all this is to invoke the metaphor of a Swiss-Army knife, with each adaptive  module the equivalent of a corkscrew, nail clipper or a myriad of cutting implements.

The revisionist viewpoint rejects this neat tailoring of mental functioning  championed by psychologists like Leda Cosmides and John Tooby. Instead, upstarts trot out the human hand as a replacement analogy for the pocket knife, a single all-purpose implement that can poke, prod, pull and push. A walk through the new thinking on evolutionary psychology appears in the Aug. 5 edition of the Philosophical Transactions of the Royal Society of London B. (The original journal, founded in 1665, was the first anywhere  to deal solely with science—and this issue is open to everyone for a download.)

The metaphor of the hand, notes Cecilia Heyes of Oxford in an introductory article, alludes to the ability of a limb extension that can “strip the defensive spines from a piece of fruit, making it safe to eat, but in Thai dancing it can also signal the smallest nuances of emotion. The human hand performs with equal facility a vast array of tasks that natural selection did and did not ‘foresee’.”

The hand analogy translates into sub-cranial physiology. On the most basic level, the new view holds that the brain did not develop through a dichotomy between higher brain functions and the automatic reflexes that enable us to catch a baseball. This can be witnessed in the neocortex and the cerebellum—executive control in the neocortex (“Don’t hit that jerk!”) is not an evolutionary plug-in that evolved independently from the sensorimotor functions of the cerebellum. Says Heyes: “The co-evolution of these structures not just in primates, but over deep evolutionary time—in all mammalian lineages—implies that in evolutionary terms the division between higher and sensorimotor intelligence, between thinking and acting, is artificial.”  In other words, it’s all one big integrated system that takes on a  functional identity when responding to the environment—a form of interaction to which academics bequeath the ponderous term “embodied cognition.”

Traditionalists assert that our Stone Age forbears developed a set of planning skills— “conceptual abstraction”— to befuddle and ultimately overpower prey. The revisionist argument counters that these and facets of cognition existed at least six million years ago in the common ancestor of chimps and humans and therefore were not just the equivalent of downloadable apps that turned up millions of years later with the arrival of the Stone Age. The evolutionary line that ultimately led to the invention of the iPhone did refine these capabilities to enhance social interactions to an extent not found in chimps, enabling hunter gatherers in the Flintstone era to function as a “unique and highly competitive predatory organism.” But both the chimp and hominid lines tended in the same direction.

The new Evo-Psych also affords a new place at the table to cultural evolution, with a lexicon influenced by the world of the gene: “differential copying of instances of cultural variants.” The totality of this emerging view of cognition replaces “special-purpose cognitive gadgets,” subject to little influence from the environment, with “domain-general” thinking machines that use a common set of computations for everything from tool-making, to mentalizing to imitating others. The nouveau Evo lends a hand to explicating how we resolve everyday social and technical problems encountered when this general-purpose cognitive maquina encounters the world beyond the eyeballs.

Source: The Wonderful Paleo Art of Heinrich Harder








Gary Stix About the Author: Gary Stix, a senior editor, commissions, writes, and edits features, news articles and Web blogs for SCIENTIFIC AMERICAN. His area of coverage is neuroscience. He also has frequently been the issue or section editor for special issues or reports on topics ranging from nanotechnology to obesity. He has worked for more than 20 years at SCIENTIFIC AMERICAN, following three years as a science journalist at IEEE Spectrum, the flagship publication for the Institute of Electrical and Electronics Engineers. He has an undergraduate degree in journalism from New York University. With his wife, Miriam Lacob, he wrote a general primer on technology called Who Gives a Gigabyte? Follow on Twitter @@gstix1.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. priddseren 1:00 pm 08/29/2012

    The theory the brain developed all of its functions simultaneously makes more sense. While evolution itself is the method that has refined life on earth to what it is today, it us more logical to start evolution with all possibilities in life and millions of years later evolution has removed the useless genes and combinations of functions leaving what is useful. The idea that totally random mutations somehow just came together the right way is what makes no sense because it leaves totally unknown the cause of these mutations and why they would happen in an adult organism somehow and then that somehow gets passed on. Starting with everything and whittling out the useless actually is possible, doesn’t require some sort of unknown mechanism to create mutations which somehow work. This fits with this article and specifically the brain. If a protobrain of the earliest organisms had basically every possible brain function that matters, then today the human brain is the result of removing all the clutter and useless components, leaving behind a human brain which has the best of the best parts of the brain left and uncluttered. The brain starting with all functions also fits the theory because the brain evolving with all of its functions from the beginning, makes more sense than somehow parts of brains from different organisms mixed with totally random mutations somehow pieced a human brain together. It also makes sense to start with a brain with all functions from the beginning which would imply the basic functions of the brain are not the parts we observe but more of the underlying way neurons connect and can be programmed to be the brain. This allows for the wide variation of brains in various animals. They all have the same basic parts, the differences are accounted for by what specific parts evolution removed or left behind in any given animal.
    The brain certainly was not pieced together like legos and I think any organism was not pieced together like legos either. A better analogy is a sculptor removing the excess marble resulting in something presumably beautiful.

    Link to this
  2. 2. jsweck 2:37 pm 08/29/2012

    Cognition only partly comes from evolution

    When we analyze or create a computing system we always have both hardware and software elements. There is no way to make a computing machine as a hardware-only or software-only entity. So when we speak of the evolution of a computer, we must separate the idea of the hardware design and the software design. Human brain hardware is determined by a genetic recipe. Like all hardware systems it’s generally fast, inflexible, and stupid.

    What about the software? Software is slow, flexible and smart. It’s either designed, or learned over the lifetime of the system. Computing systems grow in mental capability (intelligence) as they accumulate software. That software is the entity that solves their problems, serves as the locus of control, and is the stuff of perception. When used as an informational control system, we call this software system a mind.
    Minds don’t have to be complicated; they just need to be made of software (information in memory). There is no other means of making a mind. Psychology is not high level biology; it’s really about studying a software system that develops over a lifetime (far after hardware construction). Psychology always reduces to memories and experience – more software. Delusions are really software errors.

    Software is made of information, not electronics or biology. It exists in a completely different realm – memory. As long as you have memory, the existence of software is unavoidable.

    I hope this helps.

    Link to this
  3. 3. HubertB 4:57 pm 08/29/2012

    Ouch. The use of the quote by Cecilia Heyes claiming Natural Selection could have a plan in evolution treads on dangerous territory. When scientists go beyond presenting Evolution as a basic unit and get to a reason behind evolution they rightfully open the door to creationists. Undoubtedly God had just as much right to design the human hand the way he wanted to for his own purpose as Natural Selection had in designing the human hand the way it wanted to.
    No scientific article should ever claim Natural Selection designed anything with a future purpose in mind. Then it is getting into territory belonging to theologians.

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  4. 4. davidschmitt 4:58 pm 08/29/2012

    I must say there seems to be a small industry developing in which evolutionary psychology is being stereotyped with these and other similar distortions. Read any introductory evolutionary psychology textbook and you’ll see many of these issues (i.e., importance of local environment, developmental experience, cultural context, cross-species comparisons, EEAs that extend well beyond Pleistocene, etc.) are directly addressed and have long been key parts of evolutionary psychology (e.g., Buss, 2012, Chapter 2).

    To quote another’s view of this new Transactions issue, “…the papers that keep coming out that say ‘Here’s how evolutionary psychology SHOULD do things,’ and then proceed to describe the current field of evolutionary psychology as it is; reminds one of the Vaudeville joke that’s still used in movies and TV and has to be as old as humor itself: Person 1 enunciates an idea, and Person 2, seemingly ignoring Person 1, presents the same idea as if it were original and may add, just to drive the point home “I’m glad I thought of it!”

    see also,

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  5. 5. where'stheproof 6:17 pm 08/29/2012

    Comparing human evolution to evolving technology is very unscientific.

    Darwin’s theory worked well to keep the black man a slave after deeming him a monkey.

    Darwin is responsible for the Nazi depiction of the Jews and the result was genocide.

    Seems to me evolution/Darwin is a master scheme for depopulation,infanticide, abortion, euthanasia that the world elite hide behind as they dream of ridding the “useless eaters”.

    Because the government school systems, government parks and museums all babble this nonsense, does not make it true.

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  6. 6. amdurso 6:19 pm 08/29/2012

    It makes sense that most organs would evolve holistically, rather than piecemeal – after all, all the parts of the brain coexist within the same organism.

    Link to this
  7. 7. Laroquod 8:20 pm 08/29/2012

    Awkward shoehorning of an iPhone reference into an otherwise good post.

    Link to this
  8. 8. Percival 12:39 am 08/30/2012

    “The human hand performs with equal facility a vast array of tasks that natural selection did and did not ‘foresee’.”

    Of course, natural selection doesn’t actually ‘foresee’ the utility of any anatomical feature or combination of features. It works the other way around; features that confer survival advantages get passed on to progeny, and those features can have applications other than “nature intended” such as modified forefeet (hands) being useful for more than mere locomotion.

    I am slightly surprised that it apparently isn’t mainstream thinking to recognize that we (and all other extant species) are the result of the interactions of all the features, both physical and behavioral, of all our ancestors.

    Other articles in Sci Am discuss research indicating that complex behaviors previously considered to be promulgated solely by social interactions can be determined and transmitted genetically. We know that every one of our behavioral, emotive and so-called “higher functions” can be seen in our mammalian relatives; memory, planning, social and familial interactions, and emotions previously considered exclusive to humans like love and grief.

    I strongly suspect that there has been a residual religious bias subtly influencing researchers to consider humans to be somehow “special”, a bias slowly being recognized and eliminated. We are definitely different from other species intellectually and emotionally; but only in degree, not in kind.

    Link to this
  9. 9. marclevesque 6:17 pm 08/31/2012


    I don’t understand why a lot of good, and in my opinion interesting, articles get so few comments.

    Link to this

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