Excerpt from
L.Kleine-Horst: Empiristic theory of visual gestalt perception. Hierarchy and interactions of visual functions. (ETVG), Part 2 IV

Materiological and functionological stimulus concept

In traditional vision research, there is only a single concept of a (proximal) stimulus. According to which, a stimulus is a "sensory stimulus", i.e. an immediate local, physical (or chemical) influence on a sense organ. In the field of visual perception, the specific sensory stimulus consists of photons impinging onto the retina's receptors. The ETVG, too, is aware of this stimulus concept, however, "stimulus" is the superconcept to two different stimulus concepts, to both the above defined "sensory stimulus" and the "gestalt stimulus". Both are essentially different from each other. They are so different as two spheres of being are; as the sensory stimulus belongs to the material sphere and the gestalt stimulus belongs to the functional sphere of being. To this extent, one can speak of both a materiological and a functionological stimulus concept in the ETVG.

The (material) sensory stimulus is a concrete physical energy. The (functional) gestalt stimulus is an abstract relationship, which is ultimately indirectly, when not directly, to be derived from  abstract relationships between sensory stimuli. The gestalt stimulus is not a relationship between material entities, but between functional entities. Only the visual gestalt stimulus Pml, which was the very first to be called into being, is a relationship between physical functional entities. All other gestalt stimuli are relationships between psychical functional entities.

The traditional two-sphere theories (others have not existed up until now), which only know of the sensory stimulus, were not capable of reducing the system of a percept's modal-local-temporal relation- ships to a corresponding system of relationships of sensory stimuli alone. Thus the Gestaltists were compelled to assume some physiological, or physical, causes in addition to the sensory stimuli, in order to account for the perceptual deviations from the percept, which is to be expected as a result of only the sensory influences, i.e. according to the "constancy hypothesis". But they failed in this way to account for the perception; they contrived only to state global explanations, which, however, have mostly been proved to be barren, when confronted with concrete facts. Contemporary vision science, too, has not been capable of explaining in detail the data, originating mostly from laboratories, although there are enough theories trying to do so. The reason for this debacle is assumed  to be found in that these theories are two-sphere theories, which only know of the material and the phenomenal spheres of being. Only the ETVG, developed on a three-sphere model of reality, which knows the functional gestalt stimulus along with the material sensory stimulus, is capable of providing detailed explanations for a large number of facts. According to this model, there is the functional sphere "between" both the material and the phenomenal sphere. The functional sphere presents itself as a ten-level hierarchy with 25 defined (or at least definable) psychic visual factors, based on the hierarchy of four physical visual factors. Only the actualization of the psychical factors, which is performed immediately by gestalt stimuli (ultimately, i.e. indirectly, by sensory stimuli, of course), allows the specific "gestalt quality" to be created as a dependent phenomenal correlate of the respective gestalt factor. Only this theory that deduces the occurrance of a percept from the actualization of a fixed-structured hierarchy consisting of certain factors is capable of "accounting for" this percept.



1) The same gestalt factors that are actualized by the light stimuli reflected off the object edge, are actualized by the light stimuli reflected off the object surface and the object surroundings, in connection with the resulting gestalt stimuli. In this manner, the "infield" and the "outfield", adjacent to the "contour", are perceived. By the actualization of the six gestalt factors Pml to Fl, a three-dimensional "object in its surroundings" is experienced as a static, two-dimensional "figure in its outfield".

2) Each gestalt factor is actualized antagonistically in two different magnitudes: as a "positive function" and as a "negative function". This occurs via adjacent ("complementary") retinal areas.

3) This functional antagonism of the actualization of a gestalt factor has a dependent correlate, the phenomenal polarity: the appearance of two "opposite" qualities in adjacent regions of the visual field.

4) Polarity refers to the ends ("poles") of a qualitative dimension. A single, localized stimulus pattern cannot appear simultaneously as both poles.  For example: at any given time, a given part of a stimulus pattern appears either inhomogeneous or homogeneous, as line or field, as closed or open, and as figure or outfield.  Nevertheless, both poles are always present together, but at different, neighbouring locations.

5) Functional antagonism is seen as the transition of values from an absolute scale of a dimension to a relative scale. A computational system calculates the arithmetic mean of values on the absolute scale; this mean becomes the zero of the relative scale.

6) Each gestalt factor has a fourfold phenomenal effect. The qualitative-informative effect consists in informing the perceiver about a particular quale in which his environment, or an aspect of it, appears.The quantitative-informative effect allows him to experience this quality with a certain intensity. These effects correspond largely to the "reality", as far as the visual system is capable of realizing this reality. In each case, however, the intensity of the experience has been either enhanced or diminished - this is the formative effect of the respective gestalt factor. If the sensory stimulus is of such a nature, that it fulfills the "demands" of a gestalt factor's "gestalt tendency", the normative effect of this gestalt factor comes into operation, and the stimulus is experienced as being "good", as "prägnant", in respect to this "gestalt tendency".

7) Traditional perception science has only one single stimulus concept available: the "sensory stimulus", as a local physical influence on a sense organ. The ETVG distinguishes between two stimulus concepts, there are material "sensory stimuli" in the traditional sense, and there are functional "gestalt stimuli" that are hierarchically ordered abstract relations, and relation-relationships between functional effects of the sensory stimuli.  

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