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

The four phenomenal effects of a gestalt factor

1. The "system" of phenomenal effects

A (phenomenal) polar gestalt quality is the correlate of a (functional) antagonistically actualized gestalt factor. Somewhat inaccurately, one can speak of the phenomenal "effects" of a gestalt factor, inaccurately insofar as a "causal nexus" does not exist, in the scientific sense,  between the entities of two separate spheres. As long as one is aware of this epistomological difficulty, the phrase "effect" can do no harm.

Four phenomenal effects may be ascertained in the case of every gestalt factor, i.e. four different ways in which the gestalt factor is expressed phenomenally, ways in which the actualization of a gestalt factor becomes noticeable. This fourfold effect is so characteristic for a specific gestalt factor that it may in fact be used as a criterion for the identification of a gestalt factor. If one believes to have found a gestalt factor that does not exhibit these four phenomenal effects, then it is, in fact, not a gestalt factor. (For this reason, in Part 5, the "contrary course" at Level 8, has not been assumed to be a gestalt factor of its own right, but only an "aspect" of the gestalt factors T and E.) The phenomenal effects may be ordered into a logical "system":

2. The two informative effects

The "qualitative-informative" effect consists of the perceiver's information about a certain aspect of the environment. This aspect of the environment makes itself known as a particular phenomenal entity, a particular "gestalt quality". In this respect, the gestalt factor operates as a "feature detector" (a designation taken from contemporary vision science). If one knows how the qualitative- informative effect of a gestalt factor comes about, then one also knows that the designation "feature" does not really designate that which is "detected". It is in fact the case that what is detected, has "somehow" to do with the environment, because we become aware of it by means of environmental influence on our organism. Nevertheless, what is detected is not actually a property or part of the environment, it is not anything "objective", anything inherent in matter that is perceptible and noticeable "in itself". What is detected, is a relationship between things that have already been perceived, and that are themselves usually nothing but a system of relationships and interrelationships (see Parts 1 and 2).


Figure 2-22. The "logical system" of the gestalt factors' phenomenal effects.

Whereas the qualitative-informative effect of a gestalt factor is precipitated as soon as the gestalt factor is actualized above threshold, introducing its specific gestalt quality into the percept, the quantitative-informative effect of a gestalt factor is the intensity of the gestalt quality, this intensity correlating to the magnitude of actualization. This effect supplies information also about the environment, information about a particular quantitative aspect of the environment.

3. The formative effect

The informative effect of a gestalt factor consists in experiencing the object as "veridically" as possible. The formative effect of a gestalt factor tends to the changing, forming, transforming, indeed, even warping and distorting one's image of the environment, to such an extent that the world is perceived more in the sense of the factors' specific gestalt quality, than would be possible by means of the informative effect of the gestalt factor acting alone. In this way, a functional brightness difference (gestalt stimulus Dm), for example, is first of all detected as a phenomenal brightness difference (qualitative-informative effect), possessing a certain intensity (phenomenal quantitative-informative effect). But due to the formative effect of the gestalt factor Dm and its underlying active antagonism, "large" brightness differences (Dm+) are experienced as being yet larger than they would be if they corresponded to the quantitative-informative effect alone, and "small" brightness differences (Dm-) are experienced as being yet smaller (see Case Ar in Fig. 2-21). Large brightness differences, however, might also be experienced as being smaller - according to certain gestalt laws (Part 8).

It is primarily the formative effect of a gestalt factor, leading as it does to "non-veridicality" of a percept, which has stimulated empirical research to this day: one needs only to look as far as the immense volume of literature dealing with "illusions". These "illusions" are nothing other than the formative effects of those same gestalt factors, whose informative effects show us the world "veridically". Conversely, those factors that help us (by means of their informative effects) to orient ourselves with respect to the environment are the same factors that constantly deceive us about the environment. The four phenomenal effects of a gestalt factor may not be realistically separated from one another: illusions are thus in no way extraordinary or "anomalous" phenomena; indeed, they are part and parcel of our everyday perception. They usually only escape notice because we lack a standard of comparison. Such a standard is provided in laboratory experiments, in which stimulus patterns are artificially produced, in such a way that the ubiquitous "illusions" can be recognized as such.

Those "illusions" resulting from the compiled formative effects of several gestalt factors are especially popular. As researchers, however, are not even able to find the "cause" of simple illusions (those resulting from the strong formative effect of a single factor), it follows that they cannot do so when several strong factors are involved. Such illusion-patterns tend to be the object of much research; among them is the famous (and infamous) "Müller-Lyer figure" (Fig.1-2), in which at least two strongly activated factors work in concert. Another multivariate case is the "illusory figure" called "Kanizsa triangle" (Fig. 3-16).  There is an especially large amount of research to be done when factors are involved that work "at odds with each other"; the individual contribution of each factor to the illusion is very difficult to ascertain. Part 8 deals with the laws of formative effects of figure factors, the "gestalt laws", and presents, along with Part 9, several examples of "illusions" which the ETVG trys to account for, many of them usually not being termed "illusions" at all.  

4. The normative effect

The formative effect of a gestalt factor represents a change in the percept toward greater saliency of the specific gestalt quality; the normative effect of a gestalt factor consists in the formation of a reference system. The factor functions as a norm, as a "should- regulation"; one experiences how something "should" appear. Every quality should be "salient", "conspicuous", rich in brightness and color contrast, for example,  the latter meaning nothing other than that everything should be Dm+-intensive. Everything should also be well-spaced (Dl+), and separation of homogeneous (Gml-) fields (Ll-) by sharp (Gml+) contours (Ll+) is "desired". Furthermore, fields and contours should be bounded (Fl+), and should stand out from "everything else" (Fl-). Whatever corresponds to these norms, to a large degree, is experienced as "good", "pleasing", "accurate" and "satisfactory". Whatever does not correspond to such norms is experienced as "bad", "ugly", "unclear", and so forth. These expressions comprise intuitive judgements whether the appropriate configuration either fulfills the "demands", originating in the "Prägnanz-tendencies" of the gestalt factors, or does not. In this respect, a gestalt factor represents a reference system.                                 

Figure 2-23. Square and diamond with different normative effects

The normative effect of the orientation and form factors is better known than that of the figure factors; in anticipation of Part 5, let us introduce an example here. A square (Fig.2-23A) is a highly salient figure, as it fulfills not only a number of "demands" of the figure factors, as described above, but also those of the orientation and form factors "verticality/horizontality" (V/H), "straightness" (S), "measurement equality" (M), "rectangularity (R+) , and "parallelism" (R-). In contrast, Fig. 2-23B is somewhat less salient: the "geometrically" identical figure does not satisfy the demand that the contours "should" be vertically and horizontally oriented. On the other hand, they satisfy the demand of the tiltedness factor (T),  this factor, however, is located one level above the V/H factors; thus its normative effect is less strong. This means that 45° oriented lines are less "pleasing" than vertically and horizontally oriented ones; but they are more "pleasing" than lines in any other tilted orientation.

5. Relationships to other conceptions of visual perception

The entire visual gestalt perception, in the sense defined under the three-sphere theory, may be traced back to the effects of a handful of gestalt factors, and their physical basis, as well as to the direction of attention; there are no other possible ways of accounting for gestalt phenomena (provided one leaves mental influences out of consideration).

If one examines the phenomenal effects described above, bridges can be built between very different areas of research within perceptual science: neurobiology deals with the qualitative- informative effect of gestalt factors, in that it attempts to find single neurons that condition perceptual experience. Psychophysics deals with the quantitative-informative aspect of the gestalt qualities. The "Berlin/Frankfurt school" of "Gestalt Theory" stressed the normative effect, which found expression in one of their central concepts, that of the "Law of Prägnanz". The forgotten gestalt psychology of the "Leipzig school" of "Genetic 'Ganzheit' Psychology" primarily emphasized the "gestalt tendencies", i.e. the formative effect of the gestalt factors.

Finally, cognitive psychology is able to demonstrate the existence of mental factors (such as mental images, conceptions, expectations, and the conscious direction of attention). In a "top down" process, these "conceptual gestalt factors" are able to influence the lower-level "perceptual gestalt factors" of ETVG concern. Top-down processes can also be presumed within the perceptual gestalt factor hierarchy, as will be shown in Part 3.

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