Commentary on Hurford

Word Counts:

Abstract: 61

Main Text: 1208

References: 241

Entire Text: 1531

Message and Medium: Lowly and Action-Related Origins

Peter F. MacNeilage

Department of Psychology

University of Texas at Austin

Austin, TX 78712 A8000

Ph: 512 475-7009

e-mail: macneilage@psy.utexas.edu

Barbara L. Davis

Department of Communication Sciences and Disorders

University of Texas at Austin

Austin, TX 78712

Ph: 512 471-1929

e-mail: babs@mail.utexas.edu

Abstract

Hurford presents a much-needed lowly origins scenario for evolution of conceptual precursors to lexical items. But more is still needed on action, regarding both the message level of lexical concepts and the medium. We summarize our complementary action-based lowly origins (Frame/Content) scenario for the vocal auditory medium of language, which, like Hurford’s scenario, is anchored in a phylogenetically old neurological dichotomy.

Main Text

When a future history of the understanding of language evolution is written, a major 21^st century contribution may have been the widespread gut-level realization of the relevance of Darwin’s "lowly origins" metaphor: "in his bodily form, man bears the indelible stamp of his lowly origins." (Darwin, l871, p. 597) As form is in the service of function, we must necessarily seek a lowly functional origin for language. A number of issues have blocked consideration of the deep historical roots of modern language, including our characteristic anthropocentrism, the Western religious dichotomy between man and animal, endorsed by Descartes, the scientific tradition of considering language as autonomous, and the consequent tendency within the formalist linguistic tradition to ignore the question of prelinguistic evolution altogether. For most people, what could be simple ental precursors are seen as altogether too remote from language. Hurford has the courage to challenge this intuition by proposing a phylogenetically deep and therefore necessarily multistage scenario.

One criticism of Hurford’s perspective is that he could have made more of his second major conclusion from research on the neurology of vision – "that much of the visual processing in any organism is inextricably linked with motor systems." He does note that Bridgeman et al’s label of "motor oriented" for the dorsal system might be better than the label Where, He also proposes this system must play a role in attention and orientation precursors to deixis, which is in turn a precursor to labeling, and thus nominalization. Nevertheless, Hurford’s scenario remains too reminiscent of the classical approach to mind as an organ of perception of the world and cogitation, but not the organ of action that the Darwinian theory of natural selection calls for. What is selected is successful use. As Mayr has said, "Behavior (is) the pacemaker of evolutionary change" (Mayr, l982, p 612). There are two issues here. First, he neglects the importance of action beyond deixis at the conceptual or message level. Second, if one supposes that relatively early stages of language evolution occurred in a communicative context, the message level must have been interfaced with the medium, and for this an action component was also essential

Consider the message level. An early origins scenario must get beyond deixis to the fact that what you do about something – the action it affords – is is part of the mental conceptualization of a large number of environment entities, especially for predators, and the consequences of this must have been important in the evolution of syntax from the very beginning. The importance of action in conceptualization today is clearly indicated by the presence of a brain region that apparently mediates category-specific lexical representations (names) for tools. These representations must necessarily contain information regarding the actions that the tools afford. The brain region – the posterolateral part of the left inferior temporal lobe, and the lateral temporo-occipito-parietal junction (Damasio et al, l996) - is part of the What system. A chimpanzee, looking at a sapling as a potential termite wand. The subsequent decision must be based on a representation of action affordances. An additional lowly origins scenario for the anterior cingulate cortex, a major player in attentional control and in selection of appropriate action, (Gazzaniga, Ivry and Mangun, 2002) would be a desirable addition to Hurford’s proposal.

Despite this criticism, we are sympathetic to Hurford’s proposal because, like him, we also are trying to sketch out a lowly origins approach to the evolution of language. We are trying to do for the medium what he has done for the message. We also emphasize the likelihood of a multistage evolutionary process in contrast to the single stage scenario for both grammar and phonology favored by Chomsky and many other generative linguists. Furthermore, we, like Hurford, are trying to find a wormhole between linguistics and neuroscience in relating basic properties of language to a well-accepted dichotomy of mechanisms at the neurological level (See the target article by Goldberg, l985). We see our approach as complementary to Hurford’s, and consequently we will briefly spell it out here.

Our Frame/Content (F/C) theory is a conception of the evolution of the syllable according to which this basic unit of the vocal-auditory medium has deep phylogenetic roots. (See the target article by MacNeilage, l998, and also MacNeilage and Davis, 2000, 2001). The motor basis for the close-open alternation of the mouth characteristic of the syllable (closed for consonants, open for vowels) is oscillation of the mandible between elevated and depressed configurations. This movement cyclicity is proposed to have evolved for various ingestive processes (chewing, sucking, licking) in early mammals about 200 million years ago. The mandibular cycle then may have been utilized for visuofacial cyclicites (lipsmacks, tonguesmacks, teeth chatters) as observable today in many higher primates, (Redican, 1975) before it was paired with phonation in hominids to form the Frame for the syllable. Subsequently the capability of programming the frame with independently controllable Content elements (consonants and vowels) arose, in response to selection pressures to increase the message set.

In our view, the frame-content dichotomy has its neural basis in a dichotomy of motor control subsystems present in all primates. One is an "Extrinsic" system, a system which in humans allows movements to be influenced by multimodal perceptual input , whether the movements are associated with the vocal or the manual system (Goldberg, l985). The other is an "Intrinsic" system that is primarily involved in self-generated behavior, whether manual or vocal (Goldberg, l985).

A basic neurological fact relevant to the proposed evolutionary origins of the syllable is that mechanisms in ventral motor and premotor cortex, (the latter area including part of Broca’s area in humans) are specialized for the control of ingestion processes in mammals including ingestive cyclicities (Luschei and Goldberg, 1981). A key recent finding in this regard is that actions of both oral ingestion and lipsmacking have claims to be implicated in the evolution of a mirror neuron capability (Rizzolatti and Arbib, 1998) in area F5 of monkey ventral premotor cortex, the homologue of Broca’s area (Fogasy, 2003). This capability may be a precursor to the evolution of the ability of hominids to learn speech.

As suggested by its responsiveness to external input, ventral premotor cortex is part of the "Extrinsic"system. We argue that in modern humans, while ventral premotor cortex plays the main role in the production of segmental content, frame production is primarily the province of the intrinsic system, particularly the Supplementary Motor Area. The latter claim is based mainly on evidence that the SMA is implicated in the involuntary production of strings of identical consonant-vowel syllables in a number in instances of electrical stimulation or irritative lesions of the SMA and instances of apparent disinhibition of SMA output in Global Aphasics (MacNeilage and Davis, 2001).

There are major differences between Hurford’s approach to the problem of language evolution and ours, differences that are perhaps inherent in the subject matter. For example, Hurford links the message level of language with logic, while we link phylogeny and ontogeny at the level of the medium, primarily on basic biomechanical grounds. What we have in common is an attempt to establish evolutionary links between basic phenomena in linguistics and cognitive neuroscience, links that could help to reveal what we both believe to be the inevitable lowly origins of language.

References

Damasio, H., Grabowski, T.J., Tranel, D., Hichwa, R.D. & Damasio, A. (1966) A neural basis for lexical retrieval. Nature, 380,499-505.

Darwin, C. (l871) The descent of man. Chicago: Great Books, Encyclopedia Brittanica.

Fogassi, L. (2003) Action recognition in the primate motor cortex can be a basis for communication. Paper presented at the conference" "Vocalize to localize: A missing piece in the puzzling route towards language, Grenoble, January, 2003.

Gazzaniga, M.S., Ivry, R.B. and Mangun, G.R. (2002) Cognitive Neuroscience. New York: Norton.

Goldberg, G. (1985) Supplementary motor area structure and function: Review and Hypothesis. Behavioral and Brain Sciences, 8, 567-616.

Luschei, E. S. and Goldberg, L.J. (l981) Neural mechanisms of mandibular control: Mastication and voluntary biting. In J.M. Brookhart (ed.) Handbook of physiology: The nervous system, Vol. 2. Washington, D.C.: American Physiological Society.

MacNeilage, P.F. (1998) The Frame/Content theory of evolution of speech production. Behavioral and Brain Sciences, 21, 499-546.

MacNeilage, P.F., & Davis, B.L. (2000a) On the origin of internal structure of word forms. Science, 288, 527-531.

MacNeilage, P.F. & Davis, B.L. (2001) Motor mechanisms in speech ontogeny: phylogenetic, neurobiological and linguistic implications. Current Opinion in Neurobiology, 11, 696-700.

Mayr, E. (1982) The growth of biological thought. Cambridge, MA: Belknap.

Redican, W.K. (1975) Facial expressions in nonhuman primates. In L.A. Rosenblum (Ed.) Primate behavior: Developments in field and laboratory research, Vol. 4. New York: Academic Press.

Rizzolatti, G. and Arbib, M. (1998) Language within our grasp. Trends in Neuroscience, 21, 188-194.

Acknowledgment

This paper was prepared with support from research grant No.HD 27733-09 from the Public Health Service.