Presentation on theme: "NEW COLLEGE 26-28 September 2011 EMBODIED LANGUAGE AND THE ASCENT OF INTELLIGENCE Gesture and Language : Mind and Body Robin Allott."— Presentation transcript:
NEW COLLEGE September 2011 EMBODIED LANGUAGE AND THE ASCENT OF INTELLIGENCE Gesture and Language : Mind and Body Robin Allott
ABSTRACT The acquisition of language was the turning-point for the evolutionary separation of humans from apes. From this flowed the ascent of human intelligence with the ratcheting up of human mental and cultural advance as a result of interaction between individual variations in brain structure and development and continually advancing complexity of the social, technological and cultural environment (a manifestation of the Baldwin effect).
The Starting Point: Language is not an arbitrary construction Words are not arbitrarily invented forms
The sound [the word] is not a directly imitative sign but indicates a quality which the sign and the object have in common.... sounds which partly independently and partly in comparison with others produce an impression which to the ear is similar to that which the object makes upon the mind. Humboldt, W. von.  Uber die Kawisprache auf der insel Java.Trans.1971 G.C. Buck and F.A. Raven. Univ. of Miami Press. HUMBOLDT Linguistic variability and intellectual development.
Whence comes to man the art of changing into sound what is not sound? What has a color, what has roundness in common with the name that might evolve from it... why green is called green and not blue? I do not suddenly ascribe to man an arbitrary qualitas occulta - a new power providing him with the ability to create language. I do not... proceed on the basis of arbitrary or social forces but from the general animal economy. An arbitrarily thought-out language is in all senses contrary to the entire analogy of man's spiritual forces. Herder J. G.  Essay on the Origin Of Language. Trans J. H. Moran, A. Gode. Univ. Chicago Press. HERDER: ESSAY ON THE ORIGIN OF LANGUAGE
Both body and brain were involved in the acquisition and advance of language, phylogenetically and ontogenetically. The relation between mind-state and body-state was manifested not only in the patterning of emotion (the James/Lange theory) but also in the selection of words (articulatory programs) to match patterns of perception, both of external objects and also innate attitudinal patterns, "mental" structures, which went to form both language syntax and motor syntax (cf. Karl Lashley, Kant).
THE MOTOR THEORY OF LANGUAGE
The key aspect of the motor theory of language is that words, speech and language are the outcome of an exaptation of the motor control system, that is, a direct relation between aspects of the motor cortical system and the characteristic features of phonology, lexicon and syntax. Language did not arrive de novo, but came by differentiation of and building upon pre-existing systems (such as the perceptual-motor systems... ) We see the ability to comprehend and utter words as forming perceptual and motor schemas that arise in the first place from abstraction from the sensorimotor schemas that represent the objects and actions to which those words refer. From Schema Theory to Language. Arbib, Conklin, Hill 1987 OUP
Progress in neuroscience, particularly recent experimental research using fmri and other techniques and presentations in this conference, has provided material support for the motor basis of language.
MOTOR CONTROL Bernardis Gentilucci Speech and Gesture share the same communication system 2006 Neuropsychologia Graziano Taylor Moore Cooke The cortical control of movement revisited. One possibility is that the mechanisms for speech were built on a preexisting mechanism for motor control. Neuron 36, Neuron Holden Origin of speech: The motor route Abundant behavioral evidence for an intimate connection between language and motor abilities Science 303: Pulvermüller F, Shtyrov Y, Hauk O. Understanding in an instant: neurophysiological evidence for mechanistic language circuits in the brain. Brain Lang Aug;110(2): Willems Ozyurek Hagoort When Language Meets Action: The Neural Integration of Gesture and Speech Cereb. Cortex.
The origin of words From the imitation of sounds shapes and actions Then transduced into articulatory programs By motor equivalence
Has been the central process in the origin and functioning of language and the acquisition of words. What it means is that the same motor program can be executed by different sets of muscles (and joints) - e.g. writing your signature with your foot or nose or transducing the articulatory program (articulatory phonology: Browman and Goldstein) for a word into a gesture or a sound. Berthoz The Brains Sense of Movement Harvard Browman, Catherine P. and Louis Goldstein Articulatory phonology: An overview. Phonetica 49: MOTOR EQUIVALENCE
MOTOR EQUIVALENCE EXPERIMENTS Linking of words and gestures (dual expressions of meaning) can be made overt by specific controlled mind/brain operations Click: 1. to hear sounds produced by the sound-structure of animal names 2. to see picturing gestures produced by the sound-structure of animal names (for animals which make no distinctive sound) 3. To see gestures produced by the sound-structure of action words
MOTOR EQUIVALENCE Animal sounds from animal names (in various languages): Gestures from visual images: Actions from action words The Inverse Process
BRAIN SIZE The inescapable fact is that brains, and particularly human brains, have much increased in size in the course of evolution. The increase in size must have brought survival benefits and for humans it surely means that however intelligence is measured greater size has moved in step with greater intelligence - though at the individual level the correlation is not exact.
BUT … all the day-to-day routines of bodily existence require very little neural mass. Ants, bees, mice, birds, dinosaurs, manage, or managed, very well, with small, or extremely small, brains (the ratio of brain to body may be more significant, for example, for mice or other small rodents).
So why and how did humans come to acquire a brain- mass much greater than is needed for routine bodily functions ? From homo habilis to modern homo sapiens the brain grew from an average 750 cc. to cc. [Quadrupled in size relative to body mass. No known comparable increase in brain size in any other species Plotkin 1996]
HYPOTHESES 1. Social complexity 2. Foraging strategies 3. Language development
There has been intense and long-enduring discussion of these issues and many unresolved arguments with much speculation and little useful evidence.
LANGUAGE That the remarkable increase in human brain size (unmatched by any similar rate of increase in other animals) should have some relation to the equally remarkable (unmatched by other animals) evolutionary human acquisition : language, seems an obvious and plausible hypothesis.
But the debate, confusion and uncertainty about the process by which humans invented, acquired or developed language, or languages, still rages, after 2500 years. The question about the evolutionary relation of human brain-size and language goes with the unsettled question about the brain or social processes making possible another remarkable achievement, the untutored, extensive and rapid acquisition of language, complex syntaxes and massive lexicons, by children
A NEW EVO-DEVO BALDWIN EFFECT The accepted evolutionary account of the Baldwin effect was that humans, and other animals, by changing their behaviour changed their environment and so created novel potentialities for natural selection which could operate in succeeding generations, making it possible for culture to modify evolution. With the recent growth of the new discipline Evo-Devo concerned with the relation between developmental and evolutionary processes, a new application or understanding of the Baldwin effect in relation to development of the brain becomes possible.
CELL DEATH In the development of the brain, many more neurons are produced than are ultimately needed to create the mature brain. The neurons are thinned out by programmed cell death; the initial supply of neurons (twice as many as eventually survive) are in competition to establish appropriate connections. Those which do not get the necessary access to a source of NGF (nerve growth factor) die. This Neural Darwinism (in a sense completely different from Gerald Edelmans term) is natural selection at work. [Joan Styles The Fundamentals of Brain Development Harvard 2008 p Programmed cell death]
THE DYING CELL 3 neurons compete for Nerve Growth Factor. 2 win and the 3rd dies(repeating loop)
Through cell death each individual brain is sculpted to match the environment in which the brain develops (both fetally and for an extended period after birth). Cell death continues shaping the brain long after birth. For all cells, body and brain together, from 8-14 the average child loses approx billion cells a day. The average adult loses approx billion a day. [ See Biophotonics For Viewing Programmed Cell Death SciMed – Horizons 7 August 2010]
CELL DEATH AND EVOLUTION
Cell death can now be recognised as an important link between brain and environment, operating through life to permit experience to shape the brain. It is via cell death that the relation between brain-size and culture including language can be understood. A key point in the operation of this process in the developing brain is individual brain variation. Each brain is unique in many ways, including its size and the number of neurons which have to find appropriate connections to survive.
BRAIN INDIVIDUAL DIFFERENCE Natural selection can come into play on differences in brain structure derived from the culture. Increased brain size means the availability of more neurons (and more neuronal inter-connections) available to match the extending experience of the individual- and so increase the selective advantage of the individual in a changing culture. A virtuous circle is established with the better adapted and no doubt larger- brained individuals playing a larger part in shaping the environment in which the next generation will have to face natural selection and in their turn have their brains sculpted by experience.
Language in the group will account for an ever-larger segment of total cultural input to the brain and will also act as a powerful instrument in shaping the social system. A ratchet effect is established which goes to promote a persisting increase in brain- size (and skull-size co-ordinated by allometry with brain-size) until the skull-size hits the anatomical constraint of birth-canal size.
SKULL AND BRAIN SIZE The brain no doubt keeps on growing in complexity to accommodate continuing language and other cultural changes but the growth must take the form of internal re-arrangement to produce the elaborate infolding seen in the modern human brain. [The surface area of a flattened human cortex is three times larger than the inner surface of the braincase Hilgetag, Barbas Sci. Am. Feb ]
LEXICON INPUT But how does language drive this? The major new language input to the brain is through a rapidly expanding lexicon. The growing lexicon, on the motor theory of language, requires that each word creates an articulatory motor program (linked to and derived from the visual or action percept) The influx of novel words involves an increasing demand for neurons and neuronal connections. Baldwin Evo-devo is the form in which language drives growth in the size of the human brain in response to the acquisition of words.
SYNTAX ? Additional demand for neurons and connections to accommodate syntax is less significant. Language syntax can rely substantially on pre-existing organisation of the motor and visual systems, motor syntax and vision syntax, and the neurons and connections serving these.
SPEECH But of course this only goes so far in explaining the evolutionary role of language. Before the Baldwin Evo-Devo process can begin to operate to increase brain-size, there must already be language and language-related culture. There must already be words. The central question remains: WHY and HOW could speech and language have got going for humans at all? Why humans and not dogs or apes? The most plausible possibility is, as Jan Wind suggested long ago, not that there was some massive mutation but a continuing process of cerebral reorganisation. Relatively minor changes, well within the scope of inherent brain plasticity, could have made speech possible.
WHAT FORM COULD THESE CHANGES HAVE TAKEN? Recent research papers offer some possibilities:
MOTOR CORTEX FOR SPEECH Jurgens: Neuroanatomically, the step from genetically determined controlled vocal patterns is associated with the emergence of a direct connection between the motor cortex and the laryngeal motoneurons, a connection lacking in subhuman primates. Jurgens Uwe 2000 A comparison of the neural systems underlying speech and non- speech vocal utterances in Becoming Loquens ed. Bichakjian et al. Frankfurt am Main Peter Lang
INCREASED NERVE SUPPLY Kay Cartmill Balow: Hypoglossal canal and the origin of human vocal behavior The hypoglossal canal (which carries nerves controlling tongue movements) is much larger in humans than in other primates or in australopithecus. The larger canal is adapted to carry a much richer motor innervation of the tongue and so to make possible language as a uniquely human ability. "Hypoglossal canal and the origin of human vocal behavior" 1998 Kay Cartmill Balow PNAS
CONTROL OF THE LARYNX Brown Ngan Liotti A larynx area in the human motor cortex Cerebral Cortex July A human evolutionary novelty perhaps related to emergence of voluntary control of vocalisation. of vocalisation
"When Language Meets Action: The Neural Integration of Gesture and Speech Willems Ozyurek Hagoort Cereb. Cortex fMRI evidence that speech and gesture share a high-level neural integration system. "Speech and Gesture share the same communication system" 2006 Bernardis Gentilucci Neuropsychologia Experiment suggests that word and gesture are related at the levels of execution and processing with implications for the evolution of language.
BUT WHERE DID THE WORDS COME FROM ? Some, or all, of the listed cortical changes could have made speech possible for humans (but not for other primates). But for the Baldwin Evo-Devo effect to operate there had to be words. Where did they come from? Where does any individual word come from? Herder said that it was totally impossible that words should be arbitrary, that someone should invent say the word GREEN out of the top of his head for the distinctive colour Green. If he picked a set of speech sounds at random, say POGGLE, to mean Green, why should others accept and understand him. Even more impossible, how could anyone arbitrarily invent the words IF, MIND, SELF, THINK.
LANGUAGE WITHIN OUR GRASP ? Rizzolatti and Arbib argued that the discovery of mirror neurons linking responsive motor programming in the brain of an observer with observed motor patterning of action of another individual, could have been the basis for the evolution of language. The mirror neurons could have made, and still make, imitation possible, including imitation of gesture. Arbib argues that the ability to imitate is a key innovation, a neurobiological missing link for the hypothesis that primitive forms of communication based on manual gesture preceded speech in the evolution of language. A possible evolutionary path from manual skills to language. Gallese says the discovery of mirror neurons may provide a new, though still sketchy, neurobiological basis to account for the emergence of language. Rizzolatti
SO WHAT CAN IMITATION DO IN THE EMERGENCE OF LANGUAGE ? Some things can be indicated by imitation or pointing, the sky, a tree, a direction, up or down, come and go, high and low. Imitation can be used to point to objects, to indicate hearing, eating or drinking, etc. But for many things imitation is inadequate: colours - white black red, sounds, different animals. what would be imitation for a horse, a fish, a rose, a cabbage?
IMITATION IN THE BRAIN Imitation v mimicry - What matters is stored imitation (requiring commitment of neurons and interconnecting fibres) in the form of a link between word and imitated act, sound or shape so that there can be ready access to the word and what it refers to. Words are anchored in the motor patterning and are expressible as bodily and articulatory gesture. Deacon quoted by Gerhard: the everyday miracle of word meaning and reference. So could each individual word be an arbitrary invention with an equally arbitrary linking to what it related to? With Herder and Humboldt, we can say surely not.
HOW DOES THE WORD GET LINKED TO WHAT IT REFERS TO ? How was each gesture invented? Was each gesture as arbitrary as traditional linguistics says that each word is? Clearly not. A gesture is patterned by the action seen, the shape of what is seen, the sound heard, for a vocal gesture. Mirror neurons may allow transfer of the pattern of an action and the ability to reproduce the action as a gesture (not in any way arbitrary) - but imitation has to be possible for much beyond perceived action.
HOW WORDS WERE FORMED The process by which words were formed was the inverse of the process by which gestures and sounds can be generated from existing word-forms - a reverse application of motor equivalence. On seeing some one hitting something, the action patterning was by motor equivalence converted into articulatory patterning to produce a speech-sound structure, a word, directly related to the action patterning seen. Similarly on hearing an animal sound, the typical sound of a cat or a lion, the sound-patterning is transduced by motor equivalence to form a word whose structure is derived from the sound heard. Experiment slide
SUMMARISING Gestures of all kinds were generated by imitation of actions, shapes and sound. These were stored as motor programs before humans acquired speech. When cerebral reorganisation provided new direct connections between the motor cortex, the tongue and the larynx, there was a great increase in the innervation of the articulatory apparatus generally. The motor programs from gestural origins were transduced automatically (via motor equivalence) into words structured by the gestural programs. The meanings of words were automatically linked to the action, sound and shape percepts to which the gestures referred. There is still the question how words without external reference (including abstract words) could originate. This remains a matter for separate discussion. The words exist and must have come from somewhere.[now on this]now on this
Gallese Vittorio Gallese at a psychoanalytic seminar