August 10, 2010

From social intelligence to cognitive fluidity

Posted in Language and Myth tagged , at 9:47 pm by Jeremy

This section of my book draft, Finding the Li: Towards a Democracy of Consciousness, examines how humans originally developed a social intelligence which evolved over time to what’s been called “cognitive fluidity” by  renowned archaeologist Steve Mithen.  It ties in Mithen’s view with the theory of Coolidge & Wynn that enhanced working memory is responsible for this unique aspect of human cognition.  As always, constructive comments are welcomed.

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From social intelligence to cognitive fluidity

Whether our social intelligence has caused us to be fundamentally cooperative, competitive, or both, there’s one aspect of it that most researchers can agree on: it’s driven by the actions of the pfc.  And increasingly, it’s believed that most of the special capabilities of the pfc emerged from its evolution as a tool of social intelligence.  Tomasello, among others, speculates that “the evolutionary adaptations aimed at the ability of human beings to coordinate their social behavior with one another” is what underlies “the ability of human beings to reflect on their own behavior and so to create systematic structures of explicit knowledge.”[1] Another researcher notes that “the neuropsychological functions that create the capacity for culture are very much akin to those capacities attributed to executive functioning—inhibition, self-awareness, self-regulation, imitation and vicarious learning.”[2]

In this view, many of our unique abilities that are mediated by the pfc – abstract thinking, rule-making, mental time travel into the past and the future – arose not because they were in themselves vital for human adaptation but as an accidental by-product of our social cognitive skills.  Surprisingly, this phenomenon has been found to be fairly common in evolution, and has been given the name “exaptation,” meaning a characteristic that evolved for other usages and later got co-opted for its current role.  A classic example of exaptation is bird feathers, which are thought to have originally evolved for regulation of body heat and only later became used as a means of flying.[3]

What is it, then, about the pfc that could take a set of social cognitive skills and transform them into an array of such varied and astonishing capabilities?  One answer to this question might be that the pfc is connected to virtually all other parts of the brain, and this gives it the unique capability to merge different inputs, such as vision and hearing, instinctual urges, emotions and memories, into one integrated story.  This has led one research team to speculate that the “outstanding intelligence of humans” may result not from “qualitative differences” compared with other primates, but from the pfc’s combination of the same functions which may have developed separately in other species.[4] In fact, the human pfc’s connectivity is dramatically greater than that of other primates.  The celebrated neuroscientist, Jean-Pierre Changeux, notes that “from chimpanzee to man one observes an increase of at least 70 percent in the possible connections among prefrontal workspace neurons – undeniably a change of the highest importance.”[5]

At what point did the human brain stop acting like a Swiss army knife?

Archaeologist Steve Mithen has proposed an influential theory of human evolution on this basis.[6] Mithen begins with the premise that early hominids may have developed specialized, or “domain-specific” skills.  For example, they may have developed social intelligence (as discussed above), technical intelligence for tool-making, or increasing knowledge about the natural world, but they were unable to connect these intelligences together.  It’s helpful to imagine these domain-specific intelligences like the blades and tools in a Swiss army knife.  You can use each of them, but you’d be hard pressed to use them all together at the same time.[7] But, Mithen suggests, at some time in the development of the modern human mind, we developed what he calls “cognitive fluidity,” whereby we started combining these domain-specific intelligences into an integrated meta-intelligence.  He gives an example of Neanderthals who may have been socially intelligent and technically able to make clothes and jewellery, but only modern humans, in his view, made the evolutionary jump to combine these skills and make their artefacts in a particular way to “mediate those social relationships.”[8]*

Working memory acts like the blackboard of the mind

Another research team, Coolidge and Wynn, have focused their attention on a particular pfc capability, known as “working memory,” which may have been the linchpin to permit this kind of cognitive fluidity in humans.[9] Working memory is the ability to consciously “hold something in your mind” for a short time.  For example, if someone tells you a phone number and you have to go across the room to write it down, you’ll use your working memory to hold it in your mind until it’s down on paper, at which point it’s freed up for something else.  But working memory is far more than just “short-term memory.”  Comparable to the random access memory (“RAM”) of a computer, it’s the process used by the mind to keep enough discrete items up and running so they can be joined together to arrive at a new understanding or a new plan.  It’s been referred as a “global workspace… onto which can be written those facts that are needed in a current mental program,”[10] or perhaps more concisely, “the blackboard of the mind.”[11] Changeux notes that there is “a very clear difference between … higher primates and man with regard to the quantity of knowledge that they are capable of holding on working memory for purposes of evaluation and planning,”[12] and Coolidge and Wynn have gone on to argue that it’s the enhanced working memory of humans that’s the crucial differentiating factor for our uniqueness.

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[1] Tomasello, op. cit. p. 197.

[2] Barkley, R. A. (2001). “The Executive Functions and Self-Regulation: An Evolutionary Neuropsychological Perspective.” Neuropsychology Review, 11(1), 1-29.

[3] Gould, S. J., and Vrba, E. S. (1982). “Exaptation – A Missing Term in the Science of Form.” Paleobiology, 8(1: Winter 1982), 4-15.

[4] Roth, G., and Dicke, U. (2005). “Evolution of the brain and intelligence.” Trends in Cognitive Sciences, 9(5: May 2005), 250-253.

[5] Changeux, J.-P. (2002). The Physiology of Truth: Neuroscience and Human Knowledge, M. B. DeBevoise, translator, Cambridge, Mass.: Harvard University Press, 108-9.

[6] Mithen, S. (1996). The Prehistory of the Mind, London: Thames & Hudson.

[7] The Swiss army knife metaphor is attributed to Leda Cosmides & John Tooby in Mithen, op. cit. 42.

[8] It should be noted that, although Mithen contrasts modern humans with Neanderthals, the cognitive difference between the two is a matter of great controversy.  See Zilhao, J. (2010). “Symbolic use of marine shells and mineral pigments by Iberian Neandertals.” PNAS, 107(3), 1023-1028, for an argument that the difference between the two was demographic/social rather than genetic/cognitive.  However, the Neanderthal issue is not crucial to Mithen’s underlying thesis.

[9] Coolidge, F. L., and Wynn, T. (2001). “Executive Functions of the Frontal Lobes and the Evolutionary Ascendancy of Homo Sapiens.” Cambridge Archaeological Journal, 11(2:2001), 255-60. See also: Coolidge, F. L., and Wynn, T. (2005). “Working Memory, its Executive Functions, and the Emergence of Modern Thinking.” Cambridge Archaeological Journal, 15(1), 5-26.

[10] Duncan, J. (2001). “An Adaptive Coding Model of Neural Function in Prefrontal Cortex.” Nature Reviews: Neuroscience, 2, 820-829.

[11] Patricia Goldman-Rakic quoted by Balter, M. (2010). “Did Working Memory Spark Creative Culture?” Science, 328, 160-163

[12] Changeux, op. cit.

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