BRAIN EVOLUTION AND NEUROLINGUISTIC PRECONDITIONS
ww> It might seem obvious, when we think of modern humans, that
ww> language is an adaptive trait, one that makes us more able to
ww> survive in our environment. By the term "reappropriation", we mean
ww> specifically to highlight the means by which a structure or
ww> function in the repertoire of a species reaches an evolutionary
ww> state that is compatible with, and facilitates, a new function.
ww> This new function may or may not be behaviorally related to the
ww> original. The secondary function via its underlying structure may
ww> itself then be operated upon, and refined, by natural selection
ww> and, additionally, may "set in motion selection for changes in
ww> other structures" (Futuyma, 1986, p. 424).
ww> Our investigation of the origins of language concerns itself
ww> specifically with the reappropriative basis of these structures
ww> rather than subsequent adaptive mechanisms that may have shaped
ww> language as a communicative device.
In their paper the authors presents an interesting evolutionary theory
about the brain evolution and the emergence of certain neurolinguistic
preconditions for language and they do not intend, as they say, to
illuminate those mechanisms that may have shaped language as a
communicative device. So, in my opinion, their theory is not about the
origin of language, rather it is about the emergence of those
structures which being reappropiative can support the neurological
basis of the language.
ww> Rather, as we will show in detail, language came to utilize the
ww> processing strategies available from newly evolving premotor
ww> cortex paired with those aspects of neural organization that allow
ww> for amodal concept formation and yield structured abstract
ww> representations. These aspects of neural organization arose as
ww> byproducts of the evolution of the brain with respect to the
ww> regulation of repatterned motor programs dedicated to the novel
ww> manual manipulative abilities and requisite feedback circuits
ww> associated with eye-hand coordination ccompanying the hominid
ww> shift to bipedal locomotion.
In my interpretation the authors are claiming that according to their
investigations it is probable that language came to utilize those
processing strategies which were derivated from the evolving premotor
cortex. I think this is too much to say, I belive that from their datas
we could only conclude that certain brain areas( which has certain role
in the linguistic processing, also) like the POT and Broca s area are
possibly derivated from the premotor cortex.
ww> It is now generally accepted that a portion of the posterior
ww> aspect of the third frontal convolution (Broca's area) and the
ww> region including the posterior aspect of the superior temporal
ww> gyrus (Wernicke's area) of the left cerebral hemisphere (for
ww> nearly all right-handed, and most left-handed individuals) are the
ww> two brain regions most closely associated with linguistic ability.
ww> Of particular significance for our thesis is the region known as
ww> the parieto-occipito-temporal cortex (see Sanides, 1975). The POT
ww> is, in essence, an area of integration for the three neocortical
ww> sensory association areas (Pandya and Yeterian, 1985). Incoming
ww> information is extensively, locally integrated and outgoing
ww> pathways are extremely selective with respect to the parts of the
ww> brain to which they project. What we designate as the POT has been
ww> referred to as the "association area of association areas"
ww> (Geschwind's 1965 term).
ww> Specifically, the Broca s area will be shown to have inherited its
ww> functional organization from the motor association cortex from
ww> which it evolutionarily derives. In an abstract sense (i.e.,
ww> non-language- specific), the specialization of this region is
ww> temporal sequencing (Tallal and Schwartz, 1980) and the
ww> hierarchical organization of information (Greenfield, 1992).
ww> H. habilis appears to have been the first species in which
ww> researchers might agree that there is human posterior neural
ww> organization. She may therefore be considered the first potential
ww> possessor of uniquely human modality-free sensory representation.
ww> Before leaving our discussion of potential incipient language
ww> capacity in early hominids, we note that there is supporting
ww> evidence in the fossil record bearing on the phenomena of cerebral
ww> lateralization and handedness, two characteristically human traits
ww> highly correlated with language.
ww> We have concluded that there are significant differences, evident
ww> in the fossil record, that distinguish H. habilis from the
ww> australopithecines with respect to neurolinguistic preconditions.
ww> These include a demarcated Broca's area, an identifiable POT
ww> (indicative of Wernicke's area), and asymmetrical development of
ww> the cerebral hemispheres indicative of handedness. It is relevant
ww> now to ask how, and even why, such changes in structure took place
ww> in this evolutionary line.
ww> We suggest that the configuration of the association cortex,
ww> derived from primary motor and sensory cortices and motivated via
ww> selection for neural control of the evolving hand, provided a
ww> foothold for the operations involved in linguistic processing.
ww> This does not imply that the respective roles of the POT or of
ww> Broca's area in language were in any sense predetermined. Rather,
ww> functional changes in parietal and frontal structures proceeded
ww> even as did changes in the structures themselves (for general
ww> discussion of relevant principles, see Bock, 1959; Futuyma, 1986,
ww> p. 424). It is our contention that, as a consequence of the
ww> configurational compatibility, these parietal and frontal
ww> substrates were subsequently reappropriated for language and,
ww> ultimately, for linguistically formatted communication.
In my opinion this is an acceptable theory for the evolution of
certain brain areas(POT, Broca) and certein functions, indeed this
structures could be reappropiated for language, but not necessarily.
ww> The proposed cognitiveconstruct (relevant to language) most
ww> apparently compatible with this view of neurology is Jackendoff's
ww> Conceptual Structure (1983,1987, 1990, and elsewhere). To relate
ww> the discussion of CS more directly to what we have said regarding
ww> neuroanatomical structure, we suggest that CS is the cognitive
ww> construct that is produced by the POT through its interaction with
ww> Broca's area. By virtue of the POT, human sensory input is highly
ww> processed in association cortex and loses its modality-specific
ww> character; by virtue of Broca's area's influence on the POT, the
ww> amodal representations are subject to hierarchical structuring.
ww> Structured modality-neutral representation, we suggest, is the
ww> essence of CS.
ww> Importantly, CS is not part of the linguistic system per se.
I only want to accentuate thah this can be a theory for the Cs, but if
we are accepting that CS is not equal with the language, knowing
something about CS we can say nothing important about the language,
excluding the fact that certain cognitive functions ( eg hierarhical
organization, abstraction, generalisation) are used by both. I accept
that knowing a component of system we can conclude certain important
issues, but I think there have to be a component not shared by the
language and CS, which is more important for the language. The level of
CS and the level of language are completly different in my opinion. ( I
am not saying that the linguistic level is higher).I belive that, if we
have to hierarhise the level of CS can be a first representational
level, and the linguistic level can be a second level, because a
linguistic module can refer to or symbolise components of the CS.
(symbolise the symbols).
ww> However, the first step in language acquisition for H. habilis
ww> might not have been so radically different from that for the
ww> modern human child.
ww> Something very like this was reported on by Feldman, et al.
ww> (1977) for deaf children raised in linguistic isolation because
ww> their parents and other care givers thought it best not to provide
ww> them access to a manual language. These deaf linguistic isolates
ww> underwent an acquisition process with striking parallels to what
ww> might have been plausible for the first generation of language
ww> acquirers. According to Feldman et al., the children they studied
ww> created manual language; in the absence of language data they
ww> developed symbolic gestures. Furthermore, they developed
ww> gesture-order rules similar to the word-order rules devised by
ww> hearing children in the early acquisition stages. Of particular
ww> relevance to our earlier discussion of representation and
ww> structure, these deaf children demonstrated naturally-occurring
ww> segmenting behavior
I can argue here that the authors do not take in consideration that the
modern or deaf child s brain is not the same wiht the homo habilis
brain. And in the example with the deaf childs they are contradicting
theirselves: they claimed earlier that language has not evolved from
communication and now are illustrating how the deaf childs have
developed a laguage like symbolic gesture system, from gestures that
(I presume) subserve the communication. And this is the argument for the
following passage too.
ww> As is well known, primatesare noisy animals. They tend to
ww> vocalize as they execute certain behaviors and, further, certain
ww> external stimuli typically evoke particular vocalizations. It is
ww> not unreasonable to assume that H. habilis too was a noisy animal,
ww> that she had a systematic repertoire of calls. It seems not
ww> unreasonable also to think that a habiline child might have
ww> recruited from this call repertoire to create a linguistic sign
ww> (just as the deaf children recruited from the gesture repertoire to
ww> create gestural signs). These acoustic signals, simply part of the
ww> primate call system for the adult vocalizer, might have taken the
ww> form of linguistic signs in the mind of the child. This is not
ww> meant to indicate that the vocal call system became language,
ww> rather that the calls might have served as the primary data from
ww> which signs were recruited by the first language acquirers.
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