Pictorial presentation

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The Imagery debate or debate about visual presentation is a classic controversy of cognitive science . It is about the question of how to describe the cognitive processes that take place when you visualize something.

history

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For centuries, thought has been given to the visual representation in the context of an image theory of perception , see also the historical concepts of → intuition and the philosophy of → schematism . The image theory sounds plausible at first: The incident light rays project an image onto the retina . This image is then broken down and reproduced in the brain . If one accepts such a theory of perception, it is easy to explain the visual image: The images in the head generated during perception are also generated during visual imagination (without direct visual input ).

As catchy as this theory may be, it is generally rejected today: When perceiving, images are not generated in the head in the literal sense, and pictorial ideas cannot be explained in this way. To cite just one objection: If perception is actually conveyed through images in the head, then there has to be someone there (in the head) who looks at the images, otherwise they would be pointless. But that is the absurd notion of a homunculus . But how can you even find out what's really going on in your head? For a long time the answer was: not at all. So it was also the consequence that behaviorism in the first half of the 20th century rejected questions such as those about internal processes in pictorial imagination as unscientific. CG Jung's psychology deals with the phenomenon of inner images , cf. a. → Imago . The brain research has evidence of sensory projection centers contributed to a better understanding of the physiological process in the visual and pictorial images.

Pylyshyn's propositional theory

This changed with the rapid development of the neurosciences and cognitive sciences. Suddenly the question of the internal processes was more than pure speculation, and so the question of visual representation was asked again. It was primarily Stephen Kosslyn and Zenon Pylyshyn who started the debate in the 1970s. Kosslyn put forward the thesis that similar processes take place in visual imagination as in perception. Pylyshyn vehemently opposes this thesis to this day. This has to do with Pylyshyn's general idea of ​​how the mind works. He assumes that information is stored in the brain in propositional form. Proposals represent the meaning of information, regardless of the specific properties of the individual information-bearing event (so-called token ). An example:

1 The ball is red.
2 It is the case that the ball is red.
3 El ból es rojo.

These utterances have different properties, but they are all carriers of the same proposition, e.g. B. can be expressed as follows:

4 red (ball).

The proposition abstracts from the individual properties of the information carrier and reflects the general meaning. (This also means that 4. may not actually be reproduced in one of the languages ​​from 1. to 3., 4. must be formulated in a metalanguage .) In the sense of a uniform, propositional " language of the mind ", Pylyshyn assumes that the idea of ​​a red ball is also stored in the form of the proposition (4.) and not as an image. Pictorial elements are at most conceivable as functionless derivations from the propositions - i.e. H. as epiphenomena of the propositions.

Kosslyn's theory of pictorial processing

Kosslyn has been offering experiments since the 1970s that are supposed to show that the phenomenon of pictorial imagination cannot be adequately explained by means of a propositional theory. Rather, we must assume - according to Kosslyn - that pictorial representation is essentially based on the same principles as perception. A representative argument from Kosslyn is given below :

In an experiment, two identical, three-dimensional objects are placed next to each other in different positions. The test person should decide whether the objects are identical. The greater the angle of rotation required to bring the objects into line, the longer it will take people to answer the question. It seems clear that the characters have to rotate one of the objects in the imagination. If the idea is pictorial, then it is to be expected that the angle of rotation and the required time are linear to one another - because the perception sequence is simply longer if more has to be rotated. If the propositional theory is true, then there is no need for such linearity. But since it is there, we have a strong argument in favor of Kosslyn's position.

Pylyshyn does not accept such arguments. He thinks that the time intervals result from the knowledge of the test subject: They only need longer to rotate the objects at larger angles because they know that the rotation of such an object takes longer and therefore unconsciously adjust their reactions (Pylyshyn speaks of a “ Tacit-knowledge explanation ” ).

The state of the debate

Apparently the debate is difficult to decide - either party can explain the phenomena. In addition, both theories have advantages and disadvantages. Pylyshyn's explanations of the experimental results often seem ad hoc , but his theory has its strengths in terms of simplicity, uniformity and economy. So what to do One development in recent years has been to look into the brain using imaging methods to see how people really work there with visual representation.

However, even these results are by no means clear: On the one hand, it was found that, in the case of pictorial presentations, there are actually strong activities in the brain regions that are busy processing visual impressions (especially the visual cortex ). The same mechanisms sometimes seem to work here. On the other hand, neuropsychologists have found a double dissociation between imagination and visual perception. This means that perception and visual representation can be disturbed independently of one another. And this means that different mechanisms have to be used here in some cases. So the question has not been decided empirically either. The question also arises as to whether a neurobiological decision is even possible here: We will never find Pylyshyn's propositions in an imaging procedure. However, this is simply because his theory is formulated on another (the computational) level.

literature

  • Stephen M. Kosslyn , J. Pomerantz: Imagery, propositions and the form of internal representations . In: Cognitive Psychology . tape 9 , no. January 1 , 1977, ISSN  0010-0285 , pp. 52-76 , doi : 10.1016 / 0010-0285 (77) 90004-4 (reprinted in: Ned Block (Ed.): Readings in the Philosophy of Psychology. Vol. 1. MIT Press, 1980, ISBN 0-674-74876 -X .; German in Dieter Münch (Ed.): Kognitionswissenschaft. Suhrkamp, ​​Frankfurt am Main 1992, ISBN 3-518-28589-0 .).
  • Zenon W. Pylyshyn: What the mind's eye tells the mind's brain. A critique of mental imagery . In: Psychological Bulletin . tape 80 , no. 1 , July 1973, ISSN  0033-2909 , p. 1-24 .
  • Zenon W. Pylyshyn: The imagery debate: Analog media vs. tacit knowledge . In: Psychological Review . tape 88 , no. January 1 , 1981, ISSN  0033-295X , pp. 16-45 .
  • Ned Block (Ed.): Imagery . MIT Press, Cambridge / Massachusetts 1981, ISBN 0-262-02168-4 .
  • Stephen Michael Kosslyn: Image and Mind . Harvard University Press, Cambridge 1980, ISBN 0-674-44365-9 .
  • Stephen M. Kosslyn: Image and Brain. The Resolution of the Imagery Debate . MIT Press, Cambridge / Massachusetts 1994, ISBN 0-262-11184-5 .
  • Verena Gottschling: Images in the Spirit. The Imagery Debate . Mentis, Paderborn 2003, ISBN 978-3-89785-066-8 .
  • Jörg RJ Schirra : Understanding Radio Broadcasts On Soccer: The Concept 'Mental Image' and Its Use in Spatial Reasoning . In: K. Sachs-Hombach (Ed.): Images in the Spirit: For the cognitive and epistemological function of pictorial representations . Rodopi, Amsterdam 1995, ISBN 90-5183-679-1 , pp. 107-136 ( e-text ).
  • Michael Tye: The Imagery Debate . MIT Press, Cambridge / Massachusetts 1991, ISBN 0-262-20086-4 .

Individual evidence

  1. ↑ Jung, Carl Gustav: Psychological types . Collected Works. Walter-Verlag, Düsseldorf 1995, paperback, special edition, volume 6, ISBN 3-530-40081-5 , §§ 688-699

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