Toward the Language-Ready Brain: Biological Evolution and Primate Comparisons

Abstract

The approach to language evolution suggested here focuses on three questions: How did the human brain evolve so that humans can develop, use, and acquire languages? How can the evolutionary quest be informed by studying brain, behavior, and social interaction in monkeys, apes, and humans? How can computational modeling advance these studies? I hypothesize that the brain is language ready in that the earliest humans had protolanguages but not languages (i.e., communication systems endowed with rich and openended lexicons and grammars supporting a compositional semantics), and that it took cultural evolution to yield societies (a cultural constructed niche) in which language-ready brains could become language-using brains. The mirror system hypothesis is a well-developed example of this approach, but I offer it here not as a closed theory but as an evolving framework for the development and analysis of conflicting subhypotheses in the hope of their eventual integration. I also stress that computational modeling helps us understand the evolving role of mirror neurons, not in and of themselves, but only in their interaction with systems Bbeyond the mirror.B ecause a theory of evolution needs a clear characterization of what it is that evolved, I also outline ideas for research in neurolinguistics to complement studies of the evolution of the language-ready brain. A clear challenge is to go beyond models of speech comprehension to include sign language and models of production, and to link language to visuomotor interaction with the physical and social world.

Empirical approaches to the study of language evolution

“…In the second Bmimetic protolanguage^stage, vocal learning combined with preexisting gestural capabilities to yield a much richer communicative system; although this combines aspects of music and gestural protolanguages, it differs from them in not proposing any point at which gesture alone was central: learned vocal displays were there from the beginning. In this I closely follow Donald, Kendon, and others, with acknowledgement of Arbib's more nuanced Bupward spiral^concep-tion of gestural-vocal interaction (Arbib, 2005(Arbib, , 2016.…”

“…Again, I need not belabor this topic in the introduction: it is covered by many experts in this issue (Arbib, 2016;Boeckx, 2016;Friederici, 2016;Hickok, 2016). Together, this body of research clearly refutes the misconception that we know little or nothing about the brain mechanisms underlying language.…”

“…A key virtue of this model is that it takes the well-attested superiority of apes in gestural versus vocal communication as its starting point. Its prime flaw is that it has difficulties explaining why the transition to speech, which came later in the evolution of language, was so complete (Emmorey, 2005;MacNeilage & Davis, 2005;Seyfarth, 2005), as further discussed by Arbib (2016) and Kendon (2016) in this issue. The clear prediction of this model is that syntax and semantics preceded speech during evolution.…”

“…The core findings, as taught in introductory courses in linguistics or psychology of language, have been reviewed in detail in many places (e.g., Crystal, 2003;Yule, 2006). Although the correct theoretical and philosophical framework for understanding this picture remains a topic of discussion (see, e.g., the articles by Arbib, 2016;Chomsky, 2016;Jackendoff & Wittenberg, 2016;ScottPhillips, 2016), it all concerns modern humans and thus defines the Bend target^of any evolutionary model, rather than the steps required to get to this point. It is only rather recently that detailed theoretical models of modern language have been used to fuel hypotheses about how language evolved (e.g., Berwick & Chomsky, 2016;Givón, 2002;Hurford, 2011;Jackendoff, 2002Jackendoff, , 2010Scott-Phillips, 2014), though earlier efforts include Bickerton (1990) and Pinker and Bloom (1990).…”

“…This special issue provides a very rich selection of comparative data, including work on nonhuman primates (Arbib, 2016;Byrne & Cochet, 2016;Fischer, 2016;Lyn, 2017;Seyfarth & Cheney, 2016), birds (Fehér, 2016;Okanoya, 2017;ten Cate, 2016), bats (Vernes, 2016), or a mixture of species (Pepperberg, 2016). I will thus delve no further in this introduction into the value and virtues of comparative data.…”