sábado, 21 de marzo de 2015

La proyección mental de la realidad

Va saliendo más investigación que juega a favor de mi teoría de la proyección mental de la realidad. Por ejemplo en este artículo sobre la construcción de la información visual publicado en Current Biology.

La sustancia (y ya lo dijo en cierto modo Berkeley) es que el objeto visual es construido por el cerebro, no "recibido" ya hecho desde el exterior. Yo lo llamo a veces la teoría de la  "proyección del objeto", porque el efecto viene a ser como si nuestro cerebro proyectase a la realidad el objeto que ha generado, con el resultado de que lo vemos allí afuera, cuando no está sino en nuestra cabeza. Quizá sea más apropiado llamarla, como lo hacen estos autores, la teoría de la "integración del objeto."

Integration Trumps Selection in Object Recognition

http://www.cell.com/current-biology/abstract/S0960-9822%2815%2900132-3





Highlights

  • Humans identified letter shapes defined by texture, color, and luminance cues
  • Humans integrate cues that define the same letter for improved shape recognition
  • They cannot filter out cues that define a conflicting letter, reducing performance
  • Mandatory cue integration results in a failure of attentional selection

Summary

Finding and recognizing objects is a fundamental task of vision. Objects can be defined by several “cues” (color, luminance, texture, etc.), and humans can integrate sensory cues to improve detection and recognition [ 1–3 ]. Cortical mechanisms fuse information from multiple cues [ 4 ], and shape-selective neural mechanisms can display cue invariance by responding to a given shape independent of the visual cue defining it [ 5–8 ]. Selective attention, in contrast, improves recognition by isolating a subset of the visual information [ 9 ]. Humans can select single features (red or vertical) within a perceptual dimension (color or orientation), giving faster and more accurate responses to items having the attended feature [ 10, 11 ]. Attention elevates neural responses and sharpens neural tuning to the attended feature, as shown by studies in psychophysics and modeling [ 11, 12 ], imaging [ 13–16 ], and single-cell and neural population recordings [ 17, 18 ]. Besides single features, attention can select whole objects [ 19–21 ]. Objects are among the suggested “units” of attention because attention to a single feature of an object causes the selection of all of its features [ 19–21 ]. Here, we pit integration against attentional selection in object recognition. We find, first, that humans can integrate information near optimally from several perceptual dimensions (color, texture, luminance) to improve recognition. They cannot, however, isolate a single dimension even when the other dimensions provide task-irrelevant, potentially conflicting information. For object recognition, it appears that there is mandatory integration of information from multiple dimensions of visual experience. The advantage afforded by this integration, however, comes at the expense of attentional selection.


 Este tipo de integración cognitiva en el cerebro resulta (claro está) de su complejidad de circuitos neuronales que procesan diversa información, parte proveniente del córtex, de la memoria, combinándola con "lo que se ve."  Resulta de la historia evolutiva del cerebro, y en parte de su "recableo" provocado por la ampliación del córtex y la integración de la información lingüística en la estructura del cerebro. Más al respecto hablan Deacon (ver La caverna del cerebro) y Benjamin Bergen en Louder than Words.  La estructura del cerebro, el desarrollo del lenguaje y la integración de nuestra cultura y experiencia con nuestra percepción generan así la realidad virtual o realidad aumentada  donde vivimos. Para otros seres con ojos no está ahí—pero nosotros la vemos; y es más, nos movemos por ella y vivimos en ella.

La noción de estroma propuesta por Gustavo Bueno viene a ser una manera de enfocar el mismo fenómeno, visto desde su teoría. El "estroma" es el objeto cultural, el meme mental podríamos decir, que tiene una naturaleza cognitiva e informacional pero a la vez es un objeto físico. Esto da lugar a una ontología de objetos materiales gestionados y organizados por la mente.

Hablaba yo de esta cuestión de la generación mental de la realidad,  a cuenta del libro de Weiskrantz Consciousness Lost and Found, de Gazzaniga, y de las neuronas espejo, y defendiendo la tesis de la "proyección" o de la "realidad proyectada", en ESPECULACIONES NEURONALES.

Esta cuestión de neurología, de lingüística y de psicología cognitiva también tiene implicaciones filosóficas, fenomenológicas y antropológicas, claro está. Así que por qué no añadir un ingrediente más al cocido de este artículo, relacionando esta noción de la realidad aumentada gestada en el cerebro, con la teoría de la mente y de la experiencia de George Herbert Mead, que veníamos discutiendo estos días por aquí también. Entre pragmatismo y fenomenología anda la cosa, pero más que rozando la metafísica, puesto que Mead pretende explicar la generación misma de la realidad, de la realidad espacio-temporal (esos irreductibles kantianos) a través del análisis de la experiencia de contacto, y explicando la genesis del tiempo mediante la auto-interacción. En fin, se lo lean en Mind, Self and Society o en La Filosofía del presenteMead se vio influido por muchos (Dilthey, Wundt, James, Dewey, Bergson, etc.) pero muy inmediatamente aquí por las reflexiones de Alfred North Whitehead en What Is Nature. (Oigan aquí un podcast sobre la teoría de la constitución mental de la realidad del propio Whitehead, que a su vez nos lleva más atrás—a Locke, etc.). Pero dejaremos para otra ocasión, quizá para la eternidad, la teoría de la Realidad como Realidad Virtual y la organización mental del mundo según Whitehead.

Aquí sólo traeré a colación un par de textos relevantes de Mind, Self, and Society de Mead, el primero en realidad de uno de los ensayos suplementarios llamado "El individuo biológico":

From the point of view of instinctive behavior in the lower animals, or of the immediate human response to a perceptual world (in other words, from the standpoint of the unfractured relation between the impulses and the objects which give them expression), past and future are not there; and yet they are represented in the situation. They are represented by facility of adjustment through the selection of certain elements both in the direct sensuous stimulation through the excitement of the end-organs, and in the imagery. What represents past and what represents future are not distinguishable as contents. The surrogate of the past is the actual adjustment of the impulse to the object as stimulus. The surrogate of the future is the control which the changing field of experience during the act maintains over its execution.

The flow of experience is not differentiated into a past and future over against an immediate now until reflection affects certain parts of the experience with these characters, with the perfection of adjustment on the one hand, and with the shifting control on the other. The biologic individual lives in an undifferentiated now; the social reflective individual takes this up into a flow of experience within which strands a fixed past and a more or less uncertain future. The now of experience is represented primarily by the body of impulses listed above, our inherited adjustment to a physical and social world, continuously reconstituted by social reflective processes; but this reconstitution takes place by analysis and selection in the field of stimulation, not by immediate direction and recombination of the impulses. The control exercised over the impulses is always through selection of stimulations conditioned by the sensitizing influence of various other impulses seeking expression. The immediacy of the now is never lost, and the biologic individual stands as the unquestioned reality in the minds of differently constructed pasts and projected futures. It has been the work of scientific reflection to isolate certain of these fixed adjustments (in terms of our balanced postures, our movements toward objects, our contacts with and manipulations of objects) as a physical world, answering to the biologic individual with its intricate nervous system. (350-51)

Y en la primera mitad de Mind, Self, and Society, habla de cómo la mente y la consciencia no están localizadas en ningún punto concreto del cerebro, sino que son el resultado emergente de la interacción de los circuitos cerebrales entre sí:

In the cortex, that organ which in some sense answers to human intelligence, we fail to find any exclusive and unvarying control, that is, any evidence of it in the structure of the form itself. In some way we can assume that the cortex acts as a whole, but we cannot come back to certain centers and say that this is where the mind is lodged in thinking and in action. There are an indefinite number of cells connected with each other, and their innervation in some sense leads to a unitary action, but what that unity is in terms of the central nervous system it is almost impossible to state. All the different parts of the cortex seem to be involved in everything that happens. All the stimuli that reach the brain are reflected into all parts of the brain, and yet we do get a unitary action. There remains, then, a problem which is by no means definitely solved: the unity of the action of the central nervous system. Wundt undertook to find certain centers which would be responsible for this sort of unity, but there is notheing in the structure of the brain itself which isolated any parts of the brain as those which direct conduct as a whole. The unity is a unity of integration, though just how this integration takes place in detail we cannot say. (24)

Now behavioristic psychology, instead of setting up these events in the central nervous system as a causal series which is at least conditional to the sensory experience, takes the entire response to the environment as that which answers to the colored object we see, in this case the light. It does not locate the experience at any point in the nervous system; it does not put it, in the terms of Mr. Russell, inside of a head. Russell makes the experience the effect of what happens at that point where a causal process takes place in the head. He points out that, from his own point of view, the head inside of which you can place this experience exists empirically only in the heads of other people. The physiologist explains to you where this excitement is taking place. He sees the head he is demonstrating to you and he sees what is inside of the head in imagination, but, on this account, that which he sees must be inside of his own head. The way in which Russell gets out of this mess is by saying that the head which he is referring to is not the head we see, but the head which is implied in physiological analysis. Well, instead of assuming that the experienced world as such is inside of a head, located at that point at which certain nervous disturbances are going on, what the behaviorist does is to relate the world of experience to the whole act of the organism. It is true, as we have just said, that this experienced world does not appear except when the various excitements reach certain points in the central nervous system; it is also true that if you cut off any of those channels you wipe out so much of that world. What the behaviorist does, or ought to do, is to take the complete act, the whole process of conduct, as the unit in his account. In doing that he has to take into account not simply the nervous system but also the rest of the organism, for the nervous system is only a specialized part of the entire organism. (111)



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Más sobre percepción, reconocimiento y constitución perceptual de los objetos en esta conferencia de Ned Block: Seeing-as, Concepts, and Non-conceptual Content






 





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