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181.
Peter Godfrey-Smith 《Philosophical Studies》2009,145(2):273-295
182.
Ruchika Shaurya Prakash Kirk I. Erickson Stanley J. Colcombe Jennifer S. Kim Michelle W. Voss Arthur F. Kramer 《Brain and cognition》2009
We investigated the relative involvement of cortical regions supporting attentional control in older and younger adults during performance on a modified version of the Stroop task. Participants were exposed to two different types of incongruent trials. One of these, an incongruent-ineligible condition, produces conflict at the non-response level, while the second, an incongruent-eligible condition, produces conflict at both non-response and response levels of information processing. Greater attentional control is needed to perform the incongruent-eligible condition compared to other conditions. We examined the cortical recruitment associated with this task in an event-related functional magnetic resonance imaging paradigm in 25 older and 25 younger adults. Our results indicated that while younger adults demonstrated an increase in the activation of cortical regions responsible for maintaining attentional control in response to increased levels of conflict, such sensitivity and flexibility of the cortical regions to increased attentional control demands was absent in older adults. These results suggest a limitation in older adults’ capabilities for flexibly recruiting the attentional network in response to increasing attentional demands. 相似文献
183.
A central controversy in cognitive science concerns the roles of rules versus similarity. To gain some leverage on this problem, we propose that rule- versus similarity-based processes can be characterized as extremes in a multidimensional space that is composed of at least two dimensions: the number of features (Pothos, 2005) and the physical presence of features. The transition of similarity- to rule-based processing is conceptualized as a transition in this space. To illustrate this, we show how a neural network model uses input features (and in this sense produces similarity-based responses) when it has a low learning rate or in the early phases of training, but it switches to using self-generated, more abstract features (and in this sense produces rule-based responses) when it has a higher learning rate or is in the later phases of training. Relations with categorization and the psychology of learning are pointed out. 相似文献
184.
Sensory substitution devices provide through an unusual sensory modality (the substituting modality, e.g., audition) access to features of the world that are normally accessed through another sensory modality (the substituted modality, e.g., vision). In this article, we address the question of which sensory modality the acquired perception belongs to. We have recourse to the four traditional criteria that have been used to define sensory modalities: sensory organ, stimuli, properties, and qualitative experience ( Grice, 1962 ), to which we have added the criteria of behavioral equivalence ( Morgan, 1977 ), dedication ( Keeley, 2002 ), and sensorimotor equivalence ( O'Regan & Noë, 2001 ). We discuss which of them are fulfilled by perception through sensory substitution devices and whether this favors the view that perception belongs to the substituting or to the substituted modality. Though the application of a number of criteria might be taken to point to the conclusion that perception with a sensory substitution device belongs to the substituted modality, we argue that the evidence leads to an alternative view on sensory substitution. According to this view, the experience after sensory substitution is a transformation, extension, or augmentation of our perceptual capacities, rather than being something equivalent or reducible to an already existing sensory modality. We develop this view by comparing sensory substitution devices to other "mind-enhancing tools" such as pen and paper, sketchpads, or calculators. An analysis of sensory substitution in terms of mind-enhancing tools unveils it as a thoroughly transforming perceptual experience and as giving rise to a novel form of perceptual interaction with the environment. 相似文献
185.
A key question in studying consciousness is how neural operations in the brain can identify streams of sensory input as belonging to distinct modalities, which contributes to the representation of qualitatively different experiences. The basis for identification of modalities is proposed to be constituted by self-organized comparative operations across a network of unimodal and multimodal sensory areas. However, such network interactions alone cannot answer the question how sensory feature detectors collectively account for an integrated, yet phenomenally differentiated experiential content. This problem turns out to be different from, although related to, the binding problem. It is proposed that the neural correlate of an enriched, multimodal experience is constituted by the attractor state of a dynamic associative network. Within this network, unimodal and multimodal sensory maps continuously interact to influence each other’s attractor state, so that a feature change in one modality results in a fast re-coding of feature information in another modality. In this scheme, feature detection is coded by firing-rate, whereas firing phase codes relational aspects. 相似文献
186.
The present investigation combined a classical conditioning paradigm with a head–shake response (HSR) habituation task in order to evaluate the importance of dorsal hippocampal neural plasticity to spontaneous recovery. In the first experiment animals exhibited rapid HSR habituation (air stimulus to the ear) and an 85% level of spontaneous recovery following a 24 h inter-session interval. The addition of a brief tone prior to the air stimulus produced a similar pattern of habituation during the first session, but the level of spontaneous recovery was reduced (44%) during Session II. In a second experiment dorsal hippocampal lesioned rats placed on this tone/HSR paradigm responded with an 87% level of spontaneous recovery during Session II; while neocortex lesioned control rats indicated significantly reduced levels of spontaneous recovery (55%). In a third experiment bilateral injections of a general MMP inhibitor, FN-439, into the dorsal hippocampus resulted in high levels of spontaneous recovery (81%); while control rats injected with artificial cerebrospinal fluid displayed a significant attenuation of spontaneous recovery (45%). Finally, animals bilaterally injected with a specific MMP-3 inhibitor into the dorsal hippocampus indicated very similar results to those obtained following FN-439 injection. These findings indicate that animals prepared with dorsal hippocampal lesions, or injections with an MMP inhibitor, revealed an impaired association between the tone and air stimulus thus maximum spontaneous recovery was present 24 h later. Thus, it appears that the dorsal hippocampus influences habituation by conserving responses and reducing spontaneous recovery when a temporally contingent signaling cue is present. 相似文献
187.
Attempts to develop neural network models of personality have not generally used empirical data for training and validating the models. Two illustrations are provided which demonstrate the incorporation of empirical data into the modeling of behavioral responses to situations varying in closeness and hierarchical role relationships. An event-contingent recording procedure is utilized to obtain data from the same participant in multiple events for multiple situations. This data is then used in the training and validation of the neural networks. The first illustration models dominant and submissive behaviors in response to situations varying in social role status. The second illustration models agreeable and quarrelsome behaviors in response to situations varying in closeness and gender of the interaction partner. The predictions from both neural network models are consistent with previous research. 相似文献
188.
Abduction is or subsumes a process of inference. It entertains possible hypotheses and it chooses hypotheses for further scrutiny.
There is a large literature on various aspects of non-symbolic, subconscious abduction. There is also a very active research
community working on the symbolic (logical) characterisation of abduction, which typically treats it as a form of hypothetico-deductive
reasoning. In this paper we start to bridge the gap between the symbolic and sub-symbolic approaches to abduction. We are
interested in benefiting from developments made by each community. In particular, we are interested in the ability of non-symbolic
systems (neural networks) to learn from experience using efficient algorithms and to perform massively parallel computations
of alternative abductive explanations. At the same time, we would like to benefit from the rigour and semantic clarity of
symbolic logic. We present two approaches to dealing with abduction in neural networks. One of them uses Connectionist Modal
Logic and a translation of Horn clauses into modal clauses to come up with a neural network ensemble that computes abductive
explanations in a top-down fashion. The other combines neural-symbolic systems and abductive logic programming and proposes
a neural architecture which performs a more systematic, bottom-up computation of alternative abductive explanations. Both
approaches employ standard neural network architectures which are already known to be highly effective in practical learning
applications. Differently from previous work in the area, our aim is to promote the integration of reasoning and learning
in a way that the neural network provides the machinery for cognitive computation, inductive learning and hypothetical reasoning,
while logic provides the rigour and explanation capability to the systems, facilitating the interaction with the outside world.
Although it is left as future work to determine whether the structure of one of the proposed approaches is more amenable to
learning than the other, we hope to have contributed to the development of the area by approaching it from the perspective
of symbolic and sub-symbolic integration.
相似文献
John WoodsEmail: |
189.
David Ellerman 《Axiomathes》2007,17(1):19-39
Since its formal definition over sixty years ago, category theory has been increasingly recognized as having a foundational
role in mathematics. It provides the conceptual lens to isolate and characterize the structures with importance and universality
in mathematics. The notion of an adjunction (a pair of adjoint functors) has moved to center-stage as the principal lens.
The central feature of an adjunction is what might be called “determination through universals” based on universal mapping
properties. A recently developed “heteromorphic” theory about adjoints suggests a conceptual structure, albeit abstract and
atemporal, for how new relatively autonomous behavior can emerge within a system obeying certain laws. The focus here is on
applications in the life sciences (e.g., selectionist mechanisms) and human sciences (e.g., the generative grammar view of
language).
相似文献
David EllermanEmail: |
190.
According to the levels-of-processing hypothesis, transitions from unconscious to conscious perception may depend on stimulus processing level, with more gradual changes for low-level stimuli and more dichotomous changes for high-level stimuli. In an event-related fMRI study we explored this hypothesis using a visual backward masking procedure. Task requirements manipulated level of processing. Participants reported the magnitude of the target digit in the high-level task, its color in the low-level task, and rated subjective visibility of stimuli using the Perceptual Awareness Scale. Intermediate stimulus visibility was reported more frequently in the low-level task, confirming prior behavioral results. Visible targets recruited insulo-fronto-parietal regions in both tasks. Task effects were observed in visual areas, with higher activity in the low-level task across all visibility levels. Thus, the influence of level of processing on conscious perception may be mediated by attentional modulation of activity in regions representing features of consciously experienced stimuli. 相似文献