This monograph explains in terms of specified neuronal brain mechanisms and systems, how the human brain does its cognitive work. It elucidates functions such as declarative and episodic learning, imagery, spatial representation, object recognition, semantic processing, narrative comprehension, planning, and motivation. Neurophysiological, psychological, and clinical findings are presented in support of the theoretical model, and a variety of computer simulation tests demonstrate its competence. -/- .

Over a decade ago, I introduced a large-scale theory of the cognitive brain which explained for the first time how the human brain is able to create internal models of its intimate world and invent models of a wider universe. An essential part of the theoretical model is an organization of neuronal mechanisms which I have named the Retinoid Model (Trehub, 1977, 1991). This hypothesized brain system has structural and dynamic properties enabling it to register and appropriately integrate disparate foveal (...) stimuli into a perspectival, egocentric representation of an extended 3D world scene including a neuronally-tokened locus of the self which, in this theory, is the neuronal origin of retinoid space. As an integral part of the larger neuro-cognitive model, the retinoid system is able to perform many other useful perceptual and higher cognitive functions. In this paper, I draw on the hypothesized properties of this system to argue that neuronal activity within the retinoid structure constitutes the phenomenal content of consciousness and the unique sense of self that each of us experiences. -/- Trehub, A. (1977). Neuronal models for cognitive processes: Networks for learning, perception, and imagination. _Journal of Theoretical Biology_ 65: 141-169. -/- Trehub, A. (1991). _The Cognitive Brain_. MIT Press. -/- . (shrink)

This paper contrasts three different schemes of reference relevant to understanding systems of perceptual representation: a location-based system dubbed "feature-placing", a system of "visual indices" referring to things called "proto-objects", and the full sortal-based individuation allowed by a natural language. The first three sections summarize some of the key arguments (in Clark, 2000) to the effect that the early, parallel, and pre-attentive registration of sensory features itself constitutes a simple system of nonconceptual mental representation. In particular, feature integration--perceiving something as (...) being both F and G, where F and G are sensible properties registered in distinct parallel streams--requires a referential apparatus. Section V. reviews some grounds for thinking that at these earliest levels this apparatus is location-based: that it has a direct and nonconceptual means of picking out places. Feature-placing is contrasted with a somewhat more sophisticated system that can identify and track four or five "perceptual objects" or "proto-objects", independently of their location, for as long as they remain perceptible. Such a system is found in Zenon Pylyshyn's fascinating work on "visual indices", in Dana Ballard's notion of deictic codes, and in Kahneman, Treisman, and Wolfe's accounts of systems of evanescent representations they call "object files". Perceptual representation is a layered affair, and I argue that it probably includes both feature-placing and proto-objects. Finally, both nonconceptual systems are contrasted with the full-blooded individuation allowed in a natural language. (shrink)

My main thesis is this paper is that, although Dretske's distinction between simple perception and cognitive perception constitutes an important milestone in contemporary theorizing on perception, it remains too coarse to account for a number of phenomena that do not seem to fall squarely on either side of the divide. I argue that what is needed in order to give a more accurate account of perceptual phenomena is not a twofold distinction of the kind advocated by Dretske but a threefold (...) distinction allowing for an intermediate level of perceptual content that is structured and yet non-conceptual. In the first section, I discuss Dretske's distinction between sensory perception and cognitive perception as well as a number of attendant notions. In section 2, two sets of phenomena that seem neither to constitute instances of sensory perception nor instances of cognitive perception as defined by Dretske are presented. I argue that they are evidence in favor of the existence of an intermediate level of perception. In section 3, I defend the view that this intermediate level of content is a level of structured non-conceptual perceptual content and I attempt to provide criteria for distinguishing among the three levels of content. (shrink)

Neuropsychological studies suggest the existence of lateralized networks that represent categorical and coordinate types of spatial information. In addition, studies with neural networks have shown that they encode more effectively categorical spatial judgments or coordinate spatial judgments, if their input is based, respectively, on units with relatively small, nonoverlapping receptive fields, as opposed to units with relatively large, overlapping receptive fields. These findings leave open the question of whether interactive processes between spatial detectors and types of spatial relations can be (...) modulated by spatial attention. We hypothesized that spreading the attention window to encompass an area that includes two objects promotes coordinate spatial relations, based on coarse coding by large, overlapping, receptive fields. In contrast, narrowing attention to encompass an area that includes only one of the objects benefits categorical spatial relations, by effectively parsing space. By use of a cueing procedure, the spatial attention window was manipulated to select regions of differing areas. As predicted, when the attention window was large, coordinate spatial transformations were noticed faster than categorical transformations; in contrast, when the attention window was relatively smaller, categorical spatial transformations were noticed faster than coordinate transformations. Another novel finding was that coordinate changes were noticed faster when cueing an area that included both objects as well as the empty space between them than when simultaneously cueing both areas including the objects while leaving the gap between them uncued. (shrink)

The Variable and Permeable Filters metaphor is presented with an explanation of its advantages over other popular metaphors in accounting for attention effects in many different research paradigms. Research from laboratories of the author and others are discussed briefly and shown to result in diverse facilitatory and inhibitory attention effects on visual perception. All of these effects are consistent with the VAP-Filters metaphor.

Studies using Posner’s spatial cueing paradigm have demonstrated that participants can allocate their attention to specific target locations based on the predictiveness of preceding cues. Four experiments were conducted to investigate attentional orienting processes operating in a high probability condition as compared to a low probability condition using various types of centrally-presented cues. Spatially-informative cues resulted in cueing effects for both probability conditions, with significantly larger CEs in the high probability conditions than the low probability conditions. Participants in the high (...) probability conditions reported little or no awareness of cue–target probabilities after task completion. Our results provide support for an implicit learning account of the proportion valid effect under experimental conditions involving spatially-informative central cues and relatively short stimulus onset asynchronies. (shrink)