Johan J. Bolhuis; Ian Tattersall; Noam Chomsky; Robert C. Berwick

“ With merge, however, the basic properties of human language emerge. Evolutionary analysis can thus be focused on this quite narrowly defined phenotypic property, merge itself, as the chief bridge between the ancestral and modern states for language. ”

“ Along with the conceptual atoms of the lexicon, the SMT holds that merge, plus the internal interface mappings to the conceptual system, yields what has been called the “language of thought” [27] .
More narrowly, the SMT also suffices to automatically derive some of the most central properties of human language syntax. For example, one of the most distinctive properties of human language syntax is that of “displacement,” along with what is sometimes called “duality of semantic patterning.” ”

“ Natural selection can be seen as one causal factor for the historical process of evolutionary change, but that is merely stating the essence of the theory of evolution. As we have argued, communication cannot be equated with language, so its evolution cannot inform the mechanisms of language syntax. ”

“ The Strong Minimalist Thesis (SMT) [17] , as discussed above, greatly eases the explanatory burden for evolutionary analysis, since virtually all of the antecedent “machinery” for language is presumed to have been present long before the human species appeared. For instance, it appears that the ability to perceive “distinctive features” such as the difference between the sound b, as in bat, as opposed to p, as in pat, might be present in the mammalian lineage generally [48] , [49] . The same holds for audition. Both comprise part of the externalization system for language. ”

“ As the text below and Figure 1 shows, merge also accounts for the characteristic appearance of displacement in human language—the apparent “movement” of phrases from one position to another. Displacement is not found in artificially constructed languages like computer programming languages and raises difficulties for parsing as well as communication. On the SMT account, however, displacement arises naturally and is to be expected, rather than exceptional, as seems true in every human language that has been examined carefully. ”

“ Contrary to recent suggestions [11] , [12] , to date there is no evidence to suggest that birdsong patterns exhibit the hierarchical syntactic structure that characterizes human language [5] , [13] , [14] or any mapping to a level forming a language of thought as in humans. Avian vocal-learning species such as parrots are able to synchronize their behavior to variable rhythmic patterns [15] . Such rhythmic abilities may be involved in human prosodic processing, which is known to be an important factor in language acquisition [16] . ”

“ While the peripheral ability to produce speech is undoubtedly a necessary condition for the expression of vocally externalized language, it is not a sufficient one, and hyoid morphology, like most other lines of evidence, is evidently no silver bullet for determining when human language originated. ”

“ Crucially, merge can apply to the results of its own output so that a further application of merge to ate and {the, apples} yields the set {ate, {the, apples}}, in this way deriving the full range of characteristic hierarchical structure that distinguishes human language from all other known nonhuman cognitive systems. ”

“ Furthermore, the general constraint of efficient computation would also seem plausibly antecedent in the cognitive computation of ancestral species. The only thing lacking for language would be merge, some specific way to externalize the internal computations and, importantly, the “atomic conceptual elements” that we have identified with words. ”

“ Lacking both, as in the case of language, makes the explanatory search more difficult. In addition, evolutionary analysis of language is often plagued by popular, naïve, or antiquated conceptions of how evolution proceeds [28] , [31] . That is, evolution is often seen as necessarily a slow, incremental process that unfolds gradually over the eons. ”

“ Jacobs, Z & Tribolo, C, “Emergence of modern human behavior: Middle Stone Age engravings from South Africa”, Science 295: 1278–1280, [ [pmid:11786608 HenshilwoodCd'ErricoFYatesRJacobsZTriboloCet al] ] ↑ McDougall, I; Brown, FH & Fleagle, JG, “Stratigraphic placement and age of modern humans from Kibish, Ethiopia”, Nature 433: 733–736, [ [pmid:15716951 McDougallIBrownFHFleagleJG] ] ↑ Clark, JD ”