The Ontogenesis of the Gurwitschian Perceptual Structure Part I

Date: Sat 09 Aug 2003 - 01:41:09 GMT

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    The Ontogenesis of the Gurwitschian Perceptual Structure: A Model for its Investigation in Preverbal Infants

    by Joe E. Dees


    The experimental methodology of genetic epistemology is discussed. Difficulties in its use to investigate the ontogenesis of perceptual structure arising from the maturation of the sensorimotor stage prior to verbal facility are discussed. Kraft's evidence for a physical substrate for Piaget's developmental stages is reviewed. Gurwitch's theme - thematic field - margin structure is outlined. It is conjectured that Kraft's evidence also supports the ontogenesis of Gurwitsch's structure. The use of semiotics to extend Piaget's methodology to preverbal infants is proposed, and a prior study be Lewis and Brooks-Gunn is outlined as an example of such an extension. Two experiments are proposed to investigate the development of visuospatial and auditory structure in preverbal infants. Possibilities for the use of phenomenology, genetic epistemology and semiotics as aids to the investigations of cognitive science are explored, and the interrelations of the disciplines are discussed.


    A plethora of studies have been conducted on the development of child cognition, with the main influence in the field being the French structuralist Jean Piaget. His work on genetic epistemology and the equilibration of cognitive structures has largely framed the context within which subsequent explorations have been formulated. The reason for this pervasive influence is that the investigative methodology of genetic epistemology is one of observation of verbal and manipulative behavior, and thus has been well received by behavioristically oriented psychologists. This is true in spite of the fact that Piaget himself may fairly be characterized as a cognitivist of the emergent mentalist stripe. In Piagetian-type studies, the evolution of child cognition is inferred from the frequiency and types of mistakes children of diverse ages make during responses to questions and the performance of various tasks. If Piaget was correct, however, concrning the order of succession of his developmental stages, the ontogenesis and development of perceptual structures would of necessity be much more difficult to ascertain, since it would occur prior to the development of symbolic verbal facility. Perception, unlike manipulative or communicative action, is not open to direct outside observation. Furthermore, even the verbal child lacks the experience of adult perception, and thus cannot compare his or her own with it in order to report observed differences. Ut is highly likely that Piaget was indeed correct. In an important review, R. Harner Kraft (1985) has provided, via the correlations of the work of others, evidence of a physical substrate for Piaget's developmental stages by perusing a number of studies of the cerebra of children who died at various ages. The myelination of different structures and connections within the developing brain at certain critical periods seems to parallel the appearance of new Piagetian cognitive capacities within the child at those periods, and the structures (and their connections) so myelinated are areas of the brain commonly associated with these capacities. Myelination both canalizes and increases the efficiency of axonal impulse transmission. According to Kraft, the visual and primary sensorimotor cortices, as well as the subcortical acoustic fibers from the cochlear nerve to the medial geniculate nucleus in the thalamus, complete their myelinogenetic cycle prior to the major myelination of the corpus callosum and the projections from the medial geniculate nucleus to the temporal lobe cortical analyzer. The intrahemispheric association and supralimbic cortical fibers mature later, and the fibers interconnecting the nonspecific associational cortices later still. At this point the nonferal child is developmentally capable of verbally describing his/her perceptual structures to others, but they will have already completed their developmental cycle. Seeing and hearing mature prior to the ability to abstractly say how one sees or hears, and thus the develoment of the child's visuospatiol and auditory structures is verbally indescribable by the child.


    The theme - thematic field - margin structure was proposed by the phenomenologist Aron Gurwitsch (1957). According to Gurwitsch, within every perceptual or conceptual field there is always a theme, or focus of intention, surrounded by a thematic field, or context, which is in turn bounded by a margin, or fringe. Visually, this structure is primarilyspatial; in audition it is mainly temporal, and if our focus is an internally grasped concept, its thematic field consists of other concepts relevant to it. The focus can be narrowed or widened at will with an adjustment of one's scope of attention, but one loses in intensity what one gains in extension. The demarcation between the theme and its field is neither smoothly sloped nor radically discontinuous, and the margin fades into nonawareness at the limits of the structure. If this seems both Gestaltist and somewhat Piagetian, it must be remembered that both Piaget and phenomenology were influenced by Gestalt theory. In fact, a perusal of Piaget's development of child cognition from syncretism (combining elements that do not belong together) and juxtaposition (bifurcating elements that do belong together) to correct discrimination and synthesis supports the view that, in cognition at least, Piaget has approximately described the ontogenesis of Gurwitsch's theme - thematic field - margin structure. Kraft's data can also be read to indicate the perceptual ontogenesis of Gurwitsch's theme thematic field - margin structure. From primarily unorganized visuo-spatial and auditory fields subserved by relatively isolated and nonspecialized cerebral hemispheres, by the age of two years one might expect such structures to emerge in the visual and auditory systems consequent upon visual, acoustic and sensorimotor myelination. In addition, Kraft notes that the development of specific capacities in a cerebral hemisphere occurs in parallel with the increase of interhemispheric connection and communication, and tends to inhibit the duplication of these functions and abilities within the other hemisphere. Interhemispheric co-operation and interhemispheric specialization seem to mutually reinforce, avoiding redundancy. Would the appearance of such a structure have to follow the myelination of the corpus callosum, or could both hemispheres, the left in audition and the right visually, manifest it prior to efficient interconnection? Or is such a perceptual structure hard- wired? Up until recently, it has been impossible, for the reasons previously stated, to discern.

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