Excerpt from
L.Kleine-Horst: Empiristic theory of visual gestalt perception. Hierarchy and interactions of visual functions. (ETVG), Part 6, IV

What "is" attention?

1. Science at a loss

This will be an amusing chapter. It is called "attention". The experimenters are familiar with the important role played by attention in perception; they know that what is seen with increased attention is different from that what is seen with decreased attention. So what do they do? They become afraid, and arrange their experiments so that the attention, directed by the subject toward the object to be perceived, remains as constant as possible: they tell the subject to fix their gaze at a certain point because they know that with every change of the visual focus, the attention relationships in the object's surroundings change as well, thus leading to a change in the experiencing of the object. Of course, even with a very keen focusing of the gaze, natural ("physiological") eye movements are unavoidable; for this reason, several experiments are carried out, from which an average value is determined (with the aid of statistical procedures).

The experimenters do all of this. There is only one thing that they do not do: they do not systematically investigate the obviously existent effect of attention on perceptual experience. Admittedly, general investigations of attention do exist; they were conducted by Wilhelm Wundt, head of the world's first institute for experimental psychology at the university of Leipzig. What did the investigators find? Nothing other than that what everybody already knows from 18 to 80 years of everyday experience with attention.

Not only the experimenters but the theorists, too, are afraid of attention; they do not know what to begin with it, and so they ignore it. But when, in a theory of perception, such a fundamental part of the relationship between human beings and their surroundings is swept under the carpet, one might as well sweep the entire theory under the carpet.

On one hand there were the Behaviorists; they had a large number of followers, and hampered the advance of psychology in that they only admitted that which was "objectively" verifiable as scientifically relevant, and thus primarily investigated observable human behavior, but not processes of consciousness such as thoughts, imagination, and perceptual experiences. They banned instincts, biological drives, interests, feelings, and attention from their research. It is especially clear that no acceptable theory of perception could come from the Behaviorists; for them, perceptual experiences were not material for scientific debate.

In addition to the Behaviorists, there was a second group of psychologists: the Gestalt psychologists. They were split into two "schools": the Berlin "Gestalt theorists", in the visual domain predominantly with Wertheimer, Köhler, Koffka and Metzger, and the Leipzig "Genetic 'Ganzheit' Psychology", predominantly with Krueger, Sander, Volkelt und Wellek. Elsewhere, I have already touched upon Sander's antiscientific interest in ignoring the influence of attention on the actual genesis of visual percepts (Kleine-Horst 1992c). The Berlin school, too, had an interest in ignoring attention as a perceptual factor, which they did quite successfully. Attention did not fit into their theory, so they did not trouble themselves to report about it. It is no wonder then that in the 18 chapter headings and 181 subheadings in Metzger's (1953) excellent and very clear book on laws of sight, the word "attention" is not found once. In his likewise well known book "Psychologie", Metzger (1954) makes an "attempt at an introduction to the present stand of general theoretical psychology..." (p.VII) from the point of view of Gestalt theory. There are in fact references to the subject "attention" in the index of this book, 27 of them, but ten of these are double references, leaving us with 17 actual references. These fall under the heading "Attention. Theories of attention". By combining two very different concepts under one heading, Metzger adroitly conceals his inability to contribute anything of factual or gestalt  theoretical   significance   to   the  subject;   the   majority  of references concern "theories of attention", attempts by earlier psychologists to account for the holistic nature of perception using the effects of attention, attempts which are discredited by Metzger. For how Köhler dealt with "attention" when accounting for figural after-effects see Part 10.

Such a treatment of the subject, however, seems to be sufficient for the "state of general theoretical psychology". In the 637 page handbook "Vision and Visual Perception", edited by Graham and Bartlett (1965), there is a total of two entries concerning attention among the approximately 3.800 entries in the index. One of these entries concerns the "fluctuation" of attention in connection with the sudden switch of interpretation in ambiguous figures; the other entry concerns an instance in which "attention" was briefly mentioned in quotation marks.

In the German literature of the twenties on visual science, especially in the experimental work of Wertheimer and Koffka`s students, there are a number of occasional references to the effects of increased or decreased directing of attention on the experience of a stimulus pattern. But the "panic" experienced by the psychologists when confronted with attention, of which they could neither make head nor tail, was to such a degree that they did not even make a tentative effort to treat the empirically established effects of attention theoretically. They did not even gather these empirically established effects together, so that one might attempt to arrive at a first recognition of general laws by abstraction. Had they done this, they would have discovered in the twenties what I did thirty-five years later, namely the manifold interactions between the perceptual factors, known to them as "Prägnanz tendencies", as well as further perceptual factors not known to them at the time. Perhaps they would have even discovered the hierarchical ordering of these perceptual factors, but this only at the expense of giving up their unproductive theory.

The neglect of attention is global. Thus Rock (1975) established that little is known about attention, although it is "vital" for the description of figures. In the same year, Egeth and Bevan (1973, p.396) stated:

Today, the biologistical reduction of the psychic entities is in full swing. Research of attention, too, is affected by this trend, and of course physiological explanations of every type have been found; but for all this, we are not any closer to an understanding of attention. The desolate state  of scientific knowledge, regarding attention, was described well by Rützel (1977):

Today, most visual scientists are natural scientists. A fundamental dogma of natural scientists is that only what is expressable in terms of numbers and measurements is scientifically relevant. The amount of attention directed toward an object, however, is not immediately expressible in terms of numbers and measurements. Consequently, attention is nonexistent for natural scientists - what is existent for them, perhaps, are those measurable physiological processes connected with directing of attention. The result of this physiological investigation of attention, expressed briefly, is:

And the book "Attention" by Moray (1972, p.178), from which this quotation is taken, ends in turn with a quotation:

These words come from O.Külpe in the year 1895. The helplessness of scientists when confronted with attention is so old, simply because it cannot be traditionally measured.

The helplessness of scientists in the face of attention is expressed also in the multitude of "definitions". For Stumpff attention is a "feeling", for E.Mach it is the "will to see". Erdmann interpreted it as "psychic energy", and Henning (1925) takes it to be the "mental" condition or physiological precondition of certain experiences". For Rohracher (1953, p.26) it is "the conscious employment of psychic functions, the experience of their activities".

For Birbaumer (1975, p.63) it is "the 'ability' of the nervous system to effect a selective increase in activity", and for Hebb (1949) it is "a central facilitation of a perceptual activity" (p.102) or a "central reinforcement of a sensory process" (p.37). Neisser (1974) offers the following reasonable definition (also acceptable by the ETVG):

L.Kaufman (1974) devotes nearly 6 out of 580 pages to attention, predominantly concerning auditory perception. More is not necessary; as far as he is concerned, "attention" and "perception" are synonymous expressions:

Reading these "definitions", one must admit that Egeth and Bevan (1973) are right when they call the field of attention research a "hodgepodge". It is, however, amusing, that they believe it possible to rectify the situation in that they recommend introducing precisely that which gave rise to it in the first place: "exact definitions":

Admittedly, this was the stand in the late seventies, which I found in the early 80th. In  the meantime, more attention has been paid to attention in visual science.  Here  is a small list of examples from the last twelve years:  Balz and Hock (1997), Baylis and Driver (1993), Bravo and Nakayama (1992), Castiello and Umiltà (1990), Desimone and Duncan (1995), Jonides and Yantis (1988), Mack, Tang, Tuma, Kahn and Rock (1992), Müller and Rabbitt (1989), Nicoletti and Umiltà (1989), Posner and Dehaene (1994), Posner and Petersen (1990), Remington, Johnston and Yantis (1992), Spitzer, Desimone and Moran (1988), Steinman, Steinman and Lehmkuhle (1995, 1997), Stelmach and Heidman (1991), Subirana-Vilanowa and Richards (1996), Tsal (1994), Yantis and Hillstrom (1994). A view on predominantly cognitive psychology of attention is to be found in Pashler (1998), with more than 800 references. See also the editorial by Spekreijse (2000) and the following 28 papers. To revise this Part, I did not feel it necessary to read this literature, as my everyday experience with attention enables me to integrate the experienced conditions and effects of attention on visual perception into the theory. On the other hand, if one wants to confirm, or falsify, among others, the "gestalt laws" in which attention is involved, as described in Part 8, it will be necessary to  use this kind of literature.  

2. The everyday experience of attention

Everyone knows what attention "is", and precisely that is the problem: it is not esoteric enough for science. Science has to be something mysterious that not just anyone can understand. The understandable is a priori unscientific; it can be the object of, but should not characterize, scientific statements. Attention, too, must therefore be something entirely different to that what Tom, Dick and Harry understand it to be. I myself would gladly say something grand about attention, something that rises high, above the mere everyday comment, only nothing springs to mind. So instead, I have collected what I -Tom, Dick, or Harry - have personally experienced regarding attention, and here introduce it into lofty science. But only someone like me, who does not have a reputation to be thus damaged, can attempt such an undertaking.

1. I can do something with attention: specifically, I can direct it toward something. I turn myself toward something attentively. The state of being attentive always occurs in connection with an orienting, a "directing toward".

2. Directing toward is always directing toward something, whatever this something may be: an object, a person, a thought, something previously experienced, something expected in the future, something existent here or something believed to be distant. This something toward which I turn can be also a "nothing", such as in meditation. Attention can be directed (i.e. I can be turned) toward "everything one can think of", in which case it is simply alertness, i.e. readiness to experience something.

3. My attention can be attracted involuntarily. This means that, without choosing to do so, I direct my attention toward something, perhaps a lamp that suddenly lights up, or an unusal noise in the adjacent room. Involuntarily, I look at the light or strain my hearing in the direction of the source of the noise - in order to establish what it is. A sudden idea or a memory, too, can capture my attention; it need not be something perceived but it must be - so it seems to me - at least something experienced. Only that which I am experiencing (and also, for example, remembering and expecting) can attract my attention.

4. I can direct my attention toward an object also voluntarily, intentionally. Often, involuntarily attracted attention becomes voluntary attention: on one hand, that what is experienced continues to attract my attention involuntarily, my attention is held, as it were. On the other hand, I am also interested, for different reasons, in finding out what is happening, and want to observe "what will happen next". Directing visual attention is not identical to directing the gaze. "Normally", the two go together, but I can voluntarily direct my attention toward an object other than that at which I am gazing.

5. Regardless of whether I direct my attention voluntarily or involuntarily, attention always possesses a certain "strength". I can perceive objects superficially, with "distributed" attention, but I can also pay more and more attention to an object. Thus I can bring all of my attention to bear on an object, for example, when I concentrate to follow a lecture. I can even feel the effort required to keep my attention arbitrary. My entire body can express the strain of highly focused attention. I have a "feeling" for whether I am now more attentive or less. I can voluntarily increase or decrease the strength of attention directed.

6. The stronger the attention that I direct toward an object, the more exactly I perceive that object, the more details I recognize. With a cursory glance at this book, all that I register is a number of black lines. Upon closer, more attentive examination, I recognize small, individual black figures possessing particular forms. The reverse is also true: if I do not look so attentively, or if I do not listen to a lecture as attentively as I had previously, then I no longer understand everything. True, I may comprehend the gist of what is being said, which opinions the speaker holds, with respect to the topic of the lecture, but I no longer comprehend the exact context, the precise line of argument. Everything appears more diffuse, less detailed.

7. The relationship that exists between directing my attention toward one object, and withdrawing my attention from another object, belongs to my experience with attention as well. I cannot register everything simultaneously. When I devote my attention to my own thoughts or memories, I am no longer able to follow the lecture so well. The more attentively I turn toward a particular object, the less attentively I am able to focus other objects. When I direct my attention toward a particular object, I have to withdraw it from other objects. This withdrawal of attention can be so strong that I perceive nothing in my surroundings; I see nothing and hear nothing apart from that on  which I am focusing.

8. In visual perception, the directing of attention possesses a spatial gradient: when I direct my attention toward a particular point in space, then it is at this point that I perceive most intensively, and in the most differentiated manner. I perceive everything else in a less differentiated manner according to how far away it is from this point of fixation. For example: when I look at a letter on this page, I can read also the letters in the immediate vicinity quite well; but the farther away a letter is from my visual focus, the more difficult it is to recognize that letter.

9. The longer I direct my attention toward a particular object, the more my attention wanes, i.e. the more it decreases. I have the same feeling of exertion, but I am able to perceive increasingly less with the same application of effort, I understand less of what is said, or of what I read.    

10. The less my attention is held by something, the quicker it tends to spring to something else, and possibly from this new object of attention to yet another.

None of this is new to perceptual scientists, not only because they have had the same everyday experiences with attention, but also because they have verified nearly all of it by scientific means. The difference between voluntary and involuntary arttention is thus known to them, as is the "numerical limitedness" of the objects perceived or the "contents of consciousness" that one can "encompass" with attention. What I have described here as a dynamic antagonism between the attention's "directing toward" and the "withdrawal from" is referred to as "the restricted nature of consciousness" in traditional perceptual science, or to use a more contemporary term, "restricted channel capacity". The tendency of attention to spring from one object to the next is known as its "fluctuation".

Everything about attention is known to scientists, but they do not use these known relationships to increase our knowledge of the world we live in. The next chapter demonstrates how attention is involved in visual perception.

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