<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">Dear INFO-CHILDES readers,</P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">I thought I’d start the new year by surprising regular readers of this forum by agreeing, at least in part, with a theoretical position championed by Liz Bates. As noted in this forum over the last couple weeks, Liz advocated a sort of language-from-spare-parts view, and in the last couple years (for my own reasons) I’ve been arguing for something quite similar (Marcus, 2004a; Marcus 2004b, esp. Chapter 7; Marcus 2006; and in a just-published review of the genetic basis of language, Fisher & Marcus 2006). In words that I very much agree with, Bates argued that </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 43px; font-size: 13px; "> the cognitive machinery that makes us human can be viewed as a new machine constructed out of old parts (Bates, 1999, and related quotes mentioned recently on Info-Childes)</P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">At the same time, Liz’s perspective on this idea, which I think of as an extension of Darwin’s notion of descent with modification, is different from my own. For her, descent-with-modification was all about quantitative change, and the poster-child of evolutionary novelty was the giraffe: </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 43px; font-size: 13px; ">[C]onsider the metaphor of the giraffe’s neck. Giraffes have the same number of neckbones that you and I have, but these bones are elongated to solve the peculiar problems that giraffes are specialized for (i.e., eating leaves high up in the tree). As a result of this particular adaptation, other adaptations were necessary as well, including cardiovascular changes (to pump blood all the way up to the giraffe’s brain), shortening of the hindlegs relative to the forelegs (to ensure that the giraffe does not topple over), and so on… The giraffe’s neck is still a neck, built out of the same basic blueprint that is used over and over in vertebrates, but with some quantitative adjustments. It still does other kinds of “neck work”, just like the work that necks do in less specialized species, but it has some extra potential for reaching up high in the tree that other necks do not provide. If we insist that the neck is a leaf-reaching organ, then we have to include the rest of the giraffe in that category, including the cardiovascular changes, adjustments in leg length, and so on. In the same vein, our “language organ” can be viewed as the result of quantitative adjustments in neural mechanisms that exist in other mammals. (Bates, 1999) </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">In my view, Liz overemphasized the quantitative at the expense of the <I>qualitative</I>. Take color vision, for example. Much (though not everything) is known about how it arose, evolutionary, and while the process of color vision surely should be seen as the product of descent with modification, the capacity to see in color equally surely differs qualitatively from anything preceded it. In essence, the critical step involved an evolutionary process known as duplication-and-divergence. Around 400 million years ago, gene for producing photoreceptor pigment was duplicated, and one copy of the gene was then free to diverge, yielding a second photoreceptor pigment with a slightly different spectral sensitivity. At that point, it became possible for ancestral retinas to distinguish not just the amount of light (monochromatic vision) impinging upon the eye but also the nature of that light (dichromatic vision). In understanding the nature and evolution of color vision, it's important to recognize how color vision is continuous with ancestral systems for monochromatic vision, but missing the point to think of the dramatic reorganization that ensued as nothing more than quantitative change. Liz’s conception of language through the quantitative change leads to a kind of language as cognition-writ-large perspective, whereas I think that process of evolutionary tinkering very much open the possibility of genuine novelty. Rather than trying to understand language as the product of (say) little more than an exceptionally large chimp brain, I suggest that we would be best off seeing language as the product of both qualitative and quantitative change.</P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">I further depart from Liz’s company when the question of what kinds of genetic change might have taken place. In the 1999 paper quoted from above, Bates went on to suggest that</P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 43px; font-size: 13px; "> developmental neurobiologists have abandoned the idea that detailed aspects of synaptic connectivity are under direct genetic control, in favor of an activity-dependent account. There has to be something special about the human brain that makes language possible, but that “something” may involve highly distributed mechanisms that serve many other functions. </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">Here again, Bates's view seems half right; the notion that language relies on highly distributed mechanisms seems even more plausible several years later, and many (though perhaps not all) of the relevant neural regions play roles in other cognitive functions. But distribution, and even the important role of activity-dependence, do not diminish the importance of genetic contributions; in the same half decade since Bates wrote those words, it is has become amply clear that genes do in fact drive initial synaptic connectivity in very detailed ways. As I emphasized in<I> The Birth of the Mind</I>, molecular control of initial brain-wiring is both precise and powerful, even while it is flexible. Although activity-dependence (which I think of as rewiring) is crucial, endogeneous mechanisms are no less crucial; indeed, many neural hallmarks can develop in the absence of any activity at all (e.g, Crowley & Katz, 1999; Verhage, 2000). A synthetic explanation of human cognition – and human uniqueness – must look for both qualititative and quantitative changes both in what is learned and what is contributed via biology.</P><P align="right" style="text-align: right; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">– Gary Marcus </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">p.s. Brian MacWhinney alluded to a an excellent early statement of this view, in Kaplan & Werner (1963). For those interested, I tracked down the original wording: </P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 43px; font-size: 13px; ">Even in the emergence of novel functions and forms, however, there is, as a rule, an intertwining of continuous and discontinuous changes: though novel features come about by qualitative change, which necessarily implies discontinuity, the manner in which such features emerge may be gradual in various respects, e.g., there may be a gradual increase in the frequency of occurrence of the new over the old, or there may be employment of older forms for new functions before the new functions secure the formation of novel, function-specific means, etc</P><P style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; ">They in turn seem to have credited their idea to a reading of Mayr (1960), who of course traced his own work back to Darwin. </P><P align="center" style="text-align: center; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">References </SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Bates, E. (1999). Plasticity, localization, and language development. In S. H. Broman & J. M. Fletcher (Eds.), </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>The changing nervous system: Neurobiological consequences of early brain disorders</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">. New York: Oxford University Press.</SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Crowley, J. C., & Katz, L. C. (1999). Development of ocular dominance columns in the absence of retinal input. </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Nature Neuroscience</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">, 2(12), 1125-1130.</SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Fisher, S. E., & Marcus, G. F. (2006). The eloquent ape: genes, brains and the evolution of language. </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Nature Reviews Genetics</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">, 7(1), 9-20. </SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Kaplan, B. & Werner, H. (1963) </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Symbol Formation: An Organismic-Developmental Approach to Language and the Expression of Thought.</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "> Wiley. </SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Marcus, G. F. (2004a). Before the word. </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Nature</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">, 431(7010), 745. </SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Marcus, G. F. (2004b). </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>The Birth of the Mind: How A Tiny Number of Genes Creates the Complexities of Human Thought</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">. New York: Basic Books.</SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Marcus, G. F. (2006). Cognitive Architecture and Descent with Modification. </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Cognition</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">, in press.</SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 12px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Mayr, E., 1960. “The emergence of evolutionary novelties”. In Tax, S. (Ed.), Evolution after Darwin, Vol. I. Chicago: University of Chicago Press.</SPAN></FONT></P><P style="text-indent: -18px; margin-top: 0px; margin-right: 0px; margin-bottom: 12px; margin-left: 21px; font-size: 13px; "><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">Verhage, M., et al. (2000). Synaptic assembly of the brain in the absence of neurotransmitter secretion. </SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; "><I>Science</I></SPAN></FONT><FONT class="Apple-style-span" size="3" style="font-size: 13px; "><SPAN class="Apple-style-span" style="font-size: 12px; ">, 287(5454), 864-869.</SPAN></FONT></P></BODY></HTML>