Nous abordons ici l’étude de la phénoménologie des objets visuels à partir de comptes rendus verbaux, de réponses à des questions ou de descriptions spontanées, ainsi que d’associations libres. Nous demandons même parfois aux sujets de réaliser de simples croquis. Cet éventail de méthodes permet de sonder la structure profonde de la conscience visuelle. Celle-ci est avant tout révélée par ce qui n’est pas spontanément mentionné par des qualités accidentelles ou encore par des changements induits lors de variations ou ajouts (...) mineurs. Nous avons trouvé une concordance remarquable parmi un grand nombre de participants. Ceci démonte que les comptes-rendus verbaux permettent d’explorer puissamment la structure de la conscience visuelle. Tout comme le langage, les « objets visuels simples » ont des racines profondes dans la conscience. Ces fondations « invisibles » servent à définir des figures simples, un « carré » par exemple, comme des objets prototypiques et uniques. La nature des « objets visuels » implique ainsi l’existence d’un « vaste domaine invisible ». Sans une telle prise en compte, la compréhension correcte de la nature de l’objet visuel n’est pas possible. Cette découverte devrait permettre de mener à une théorie de la syntaxe formelle des formes visuelles fondamentales. (shrink)

Nous abordons ici l’étude de la phénoménologie des objets visuels à partir de comptes rendus verbaux, de réponses à des questions ou de descriptions spontanées, ainsi que d’associations libres. Nous demandons même parfois aux sujets de réaliser de simples croquis. Cet éventail de méthodes permet de sonder la structure profonde de la conscience visuelle. Celle-ci est avant tout révélée par ce qui n’est pas spontanément mentionné par des qualités accidentelles ou encore par des changements induits lors de variations ou ajouts (...) mineurs. Nous avons trouvé une concordance remarquable parmi un grand nombre de participants. Ceci démonte que les comptes-rendus verbaux permettent d’explorer puissamment la structure de la conscience visuelle. Tout comme le langage, les « objets visuels simples » ont des racines profondes dans la conscience. Ces fondations « invisibles » servent à définir des figures simples, un « carré » par exemple, comme des objets prototypiques et uniques. La nature des « objets visuels » implique ainsi l’existence d’un « vaste domaine invisible ». Sans une telle prise en compte, la compréhension correcte de la nature de l’objet visuel n’est pas possible. Cette découverte devrait permettre de mener à une théorie de la syntaxe formelle des formes visuelles fondamentales. (shrink)

Summary Franz Brentano, 1838–1917, introduced the intriguing concept of “plerosis” in order to account for aspects of the continuum that were “explained” by formal mathematics in ways that he considered absurd from the perspective of intuition, especially visual awareness and imagery. In doing this, he pointed in directions later developed by the Dutch mathematician Luitzen Brouwer. Brentano’s notion of plerosis involves distinct though coincident points, which one might call “atomic entities with parts”. This notion fits the modern concepts of “receptive (...) field” in neurophysiology, “perceptive field” in psychology and “differential operator” in the formal theory of scale space. We identify Brentano’s boundary points as the primordial atomic Gestalts of visual imagery. The concept deserves to play a key role in Gestalt theory. (shrink)

Summary Prägnanz was suggested by Max Wertheimer in the 1920s as subsuming all “Laws of Gestalt” as they apply to visual awareness. Thus, it assumes a prominent position in any account of Gestalt phenomena. From a phenomenological perspective, some visual stimuli evidently “have more Prägnanz” than others, so Prägnanz seems to be an intensive quality. Here, we investigate the intricacies that need to be faced on the way to a definition of formal scales. Such measures naturally depend both upon the (...) stimulus and upon the observer. Structural complexity bottlenecks of visual systems play a role, as well as the relevance to biological fitness, that is the affinity to the optical user interface. This positions the notion of Prägnanz squarely within the realm of biology. Indeed, the familiar “releasers” of ethology are singular cases of extremely high Prägnanz. (shrink)

The additional data, perspectives, questions, and criticisms contributed by the commentaries strengthen our view that local cortical processors coordinate their activity with the context in which it occurs using contextual fields and synchronized population codes. We therefore predict that whereas the specialization of function has been the keynote of this century the coordination of function will be the keynote of the next.

It is worthwhile to search for forms of coding, processing, and learning common to various cortical regions and cognitive functions. Local cortical processors may coordinate their activity by maximizing the transmission of information coherently related to the context in which it occurs, thus forming synchronized population codes. This coordination involves contextual field (CF) connections that link processors within and between cortical regions. The effects of CF connections are distinguished from those mediating receptive field (RF) input; it is shown how CFs (...) can guide both learning and processing without becoming confused with the transmission of RF information. Simulations explore the capabilities of networks built from local processors with both RF and CF connections. Physiological evidence for synchronization, CFs, and plasticity of the RF and CF connections is described. Coordination via CFs is related to perceptual grouping, the effects of context on contrast sensitivity, amblyopia, implicit influences of color in achromotopsia, object and word perception, and the discovery of distal environmental variables and their interactions through self-organization. Cortical computation could thus involve the flexible evaluation of relations between input signals by locally specialized but adaptive processors whose activity is dynamically associated and coordinated within and between regions through specialized contextual connections. Key Words: cell assemblies; cerebral cortex; context; coordination; dynamic binding; epistemology; functional specialization; learning; neural coding; neural computation; neuropsychology; object recognition; perception; reading; self-organization; synaptic plasticity; synchronization. (shrink)

The debate between the amodal and the grounded views of cognition seems to be stuck. Their only substantial disagreement is about the vehicle or format of concepts. Amodal theorists reject the grounded claim that concepts are couched in the same modality-specific format as representations in sensory systems. The problem is that there is no clear characterization of format or its neural correlate. In order to make the disagreement empirically meaningful and move forward in the discussion we need a neurocognitive criterion (...) for representational format. I argue that efficient coding models in computational neuroscience can be used to characterize modal codes: These are codes which satisfy special informational demands imposed by sensory tasks. Additionally, I examine recent studies on neural coding and argue that although they do not provide conclusive evidence for either the grounded or the amodal views, they can be used to determine what predictions these approaches can make and what experimental and theoretical developments would be required to settle the debate. (shrink)

Neuroclassicism is the view that cognition is explained by “classical” computing mechanisms in the nervous system that exhibit a clear demarcation between processing machinery and read–write memory. The psychologist C. R. Gallistel has mounted a sophisticated defense of neuroclassicism by drawing from ethology and computability theory to argue that animal brains necessarily contain read–write memory mechanisms. This argument threatens to undermine the “connectionist” orthodoxy in contemporary neuroscience, which does not seem to recognize any such mechanisms. In this paper I argue (...) that the neuroclassicist critique rests on a misunderstanding of how computability theory constrains theorizing about natural computing mechanisms. (shrink)

In the target article Nijhawan speculates that visual perceptual mechanisms compensate for neural delays so that moving objects may be perceived closer to their physical locations. However, the vast majority of published psychophysical data are inconsistent with this speculation.

Summary In recent years, the concept of simplicity in perception has acquired a leading role, above all thanks to scholars linked to Bayesian modeling and to theories like structural information theory derived from information theory. Unfortunately, two misleading ideas made their way into the discussion: that in perception, simplicity is equivalent to Prägnanz and that Occam’s razor plays a role in the simplicity of percepts. Here it is shown that in Gestalt theory, simplicity is only one of the factors of (...) Prägnanz and that the use of Occam’s razor is improper, because it applies only to the theories that generate, in this case, a percept, and not to the product of the theory. (shrink)

There is a broad consensus about the fundamental role of thehippocampal system (hippocampus and its adjacent areas) in theencoding and retrieval of episodic memories. This paper presents afunctional model of this system. Although memory is not asingle-unit cognitive function, we took the view that the wholesystem of the smooth, interrelated memory processes may have acommon basis. That is why we follow the Ockham's razor principleand minimize the size or complexity of our model assumption set.The fundamental assumption is the requirement of (...) solving the socalled ``homunculus fallacy'', which addresses the issue ofinterpreting the input. Generative autoassociators seem to offer aresolution of the paradox. Learning to represent and to recallinformation, in these generative networks, imply maximization ofinformation transfer, sparse representation and noveltyrecognition. A connectionist architecture, which integrates theseaspects as model constraints, is derived. Numerical studiesdemonstrate the novelty recognition and noise filtering propertiesof the architecture. Finally, we conclude that the derivedconnectionist architecture can be related to the neurobiologicalsubstrate. (shrink)

An ongoing philosophical discussion concerns how various types of mental states fall within broad representational genera—for example, whether perceptual states are “iconic” or “sentential,” “analog” or “digital,” and so on. Here, I examine the grounds for making much more specific claims about how mental states are structured from constituent parts. For example, the state I am in when I perceive the shape of a mountain ridge may have as constituent parts my representations of the shapes of each peak and saddle (...) of the ridge. More specific structural claims of this sort are a guide to how mental states fall within broader representational kinds. Moreover, these claims have significant implications of their own about semantic, functional, and epistemic features of our mental lives. But what are the conditions on a mental state's having one type of constituent structure rather than another? Drawing on explanatory strategies in vision science, I argue that, other things being equal, the constituent structure of a mental state determines what I call its distributional properties—namely, how mental states of that type can, cannot, or must co‐occur with other mental states in a given system. Distributional properties depend critically on and are informative about the underlying structures of mental states, they abstract in important ways from aspects of how mental states are processed, and they can yield significant insights into the variegation of psychological capacities. (shrink)

This paper advances the view that some explanations in cognitive science are extra-mathematical explanations. Demonstrating the plausibility of this interpretation centers around certain efficient coding cases which ineliminably enlist information theoretic laws, facts and theorems to identify in-principle, mathematical constraints on neuronal information processing capacities. The explanatory structure in these cases is shown to parallel other putative instances of mathematical explanation. The upshot for cognitive mathematical explanations is thus two-fold: first, the view capably rebuts standard mechanistic objections to non-mechanistic explanation; (...) second, this view serves to importantly widen the possibility space for non-mechanistic forms of explanation in cognitive science. (shrink)