Collaborating Authors

Expanding a Standard Theory of Action Selection to Produce a More Complete Model of Cognition

AAAI Conferences

A standard model of how brains produce natural cognition would provide a framework for organizing cognitive neuroscience research. A recent effort (Laird et al., in press) to build on consensus views of cognitive operations and produce a standard model of natural cognition started with common aspects of well-established cognitive architectures ACT-R, Sigma, and SOAR. The model captures scientific consensus on “how” the brain works, but it does not offer a coherent story for “why” the component modules (i.e., working memory, long-term memory, visual and motor areas) exist and interact in the ways described. This manuscript starts with background information on a well-cited theory of action selection, and extends that theory to a fuller explanation of decision-making, action and perception that includes a framework for the elements of cognition.

Dopamine, Learning, and Production Rules: The Basal Ganglia and the Flexible Control of Information Transfer in the Brain

AAAI Conferences

One of the open issues in developing large-scale computational models of the brain is how the transfer of information between communicating cortical regions is controlled. Here, we present a model where the basal ganglia implement such a conditional information routing system. The basal ganglia are a set of subcortical nuclei that play a central role in cognition. Like a switchboard, the model basal ganglia direct the communication between cortical regions by alerting the destination regions to the presence of important signals coming from the source regions. This way, they can impose serial control on the massive parallel communication between cortical areas. The model also incorporates a possible mechanism by which subsequent transfers of information control the release of dopamine. This signal is used to produce novel stimulus-response associations by internalizing the representation being transferred in the striatum. We discuss how this neural circuit can be seen as a biological implementation of a production system. This comparison highlights the basal ganglia as bridge between computational models of small-size brain circuits and high-level characterizations of complex cognition, such as cognitive architectures.

The SAL Integrated Cognitive Architecture

AAAI Conferences

Over the last two decades, the complementary properties of symbolic and connectionist systems have led to a number of attempts at hybridizing the two approaches to leverage their strengths and alleviate their shortcomings. The fact that those attempts have generally fallen short of their goals largely reflects the difficulties in integrating computational paradigms of a very different nature without sacrificing their key properties in the process. In this paper, we propose that biological plausibility can serve as a powerful constraint to guide the integration of hybrid intelligent systems. We introduce a hybrid cognitive architecture called SAL, for "Synthesis of ACT-R and Leabra". ACT-R and Leabra are cognitive architectures in the symbolic and connectionist tradition, respectively. Despite widely different origins and levels of abstraction, they have evolved considerable commonalities in response to a joint set of constraints including behavioral, physiological, and brain imaging data. We introduce the ACT-R and Leabra cognitive architectures and their similarities in structures and concepts then describe one possible instantiation of the SAL architecture based on a modular composition of its constituent architectures. We illustrate the benefits of the integration by describing an application of the architecture to autonomous navigation in a virtual environment and discuss future research directions.

A Model of the Phonological Loop: Generalization and Binding

Neural Information Processing Systems

We present a neural network model that shows how the prefrontal cortex, interacting with the basal ganglia, can maintain a sequence of phonological information in activation-based working memory (i.e., the phonological loop). The primary function of this phonological may be to transiently encode arbitrary bindings ofloop information necessary for tasks - the combinatorial expressive power of language enables very flexible binding of essentially arbitrary pieces of information. Our model takes advantage of the closed-class nature of phonemes, which allows different neural representations of all possible phonemes at each sequential position to be encoded. To make this work, we suggest that the basal ganglia update signal that allocates phonemes toprovide a region-specific the appropriate sequential coding slot. To demonstrate that flexible, arbitrary binding of novel sequences can be supported by this we show that the model can generalize to novel sequencesmechanism, after moderate amounts of training.

Representation Internal-Manipulation (RIM): A Neuro-Inspired Computational Theory of Consciousness Artificial Intelligence

Many theories, based on neuroscientific and psychological empirical evidence and on computational concepts, have been elaborated to explain the emergence of consciousness in the central nervous system. These theories propose key fundamental mechanisms to explain consciousness, but they only partially connect such mechanisms to the possible functional and adaptive role of consciousness. Recently, some cognitive and neuroscientific models try to solve this gap by linking consciousness to various aspects of goal-directed behaviour, the pivotal cognitive process that allows mammals to flexibly act in challenging environments. Here we propose the Representation Internal-Manipulation (RIM) theory of consciousness, a theory that links the main elements of consciousness theories to components and functions of goal-directed behaviour, ascribing a central role for consciousness to the goal-directed manipulation of internal representations. This manipulation relies on four specific computational operations to perform the flexible internal adaptation of all key elements of goal-directed computation, from the representations of objects to those of goals, actions, and plans. Finally, we propose the concept of `manipulation agency' relating the sense of agency to the internal manipulation of representations. This allows us to propose that the subjective experience of consciousness is associated to the human capacity to generate and control a simulated internal reality that is vividly perceived and felt through the same perceptual and emotional mechanisms used to tackle the external world.