A new interpretation for the results of several experiments carried out using the Gambling Task p... more A new interpretation for the results of several experiments carried out using the Gambling Task paradigm is presented that differs from that put forward by . While Damasio grounds his analysis on the somatic markers hypothesis, we propose a perspective based on the functional integration of emotion with memory that is sympathetic with the view of the prefrontal cortex endorsed by . Our interpretation is supported by the development of a computational model implemented in the ACT-R cognitive architecture. The model highlights some limitations of the architecture that arise when dealing with situations charged with emotional significance. In particular, the model-when developed according to the standard ACT-R theory-produces a perseverating behavior that replicates the performance exhibited by participants with lesions in the orbitofrontal cortex. An adjustment to the ACT-R equations describing the activation of elements in declarative memory is suggested that allows modeling the performance of both normal controls and orbitofrontal patients.
Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert ... more Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert influence on behavior, but some findings and replications of the original studies challenged this view. We investigated this topic by carrying out an experiment with the Iowa Gambling Task (IGT), where a dissociation procedure was adopted to successfully isolate possible implicit components. After a typical interaction with the IGT, participants performed a ''blind'' card selection phase without receiving any feedback. Half of them were instructed to continue choosing as they did before, the other half was told that good card decks turned bad, and vice versa, so that explicit knowledge was necessary to overcome the previously learned deck-outcome associations. The results confirmed the existence of early acquired implicit biases, confirming that previously experienced emotional events may covertly affect subsequent behavior.
Abstract In the paper we propose a revision of the Somatic Maker Hy- pothesis (henceforth SMH: Da... more Abstract In the paper we propose a revision of the Somatic Maker Hy- pothesis (henceforth SMH: Damasio, 1994). Most of the cor- roboration for this theory, as well as some contrary results, come,from an experimental decision making,paradigm,known as the Iowa Gambling,Task. We analyze the different con- stituents of the SMH and argue that the discrepancy between the theory predictions and the experiments,reported in the lit- erature can be explained by modifying,the theory to include a different functional role of somatic markers in high-order cog- nition. This revised version is in turn related to a different func- tional interpretation of the orbitofrontal cortex. Within this new,framework,we describe a detailed computational,model that is able to reproduce the original experimental data, and we show,that it can also account for the behavior deriving from other neuropsychological impairments.
The cognitive modeling of human behavior: Why a model is (sometimes) better than 10,000 words Act... more The cognitive modeling of human behavior: Why a model is (sometimes) better than 10,000 words Action editor: Ron Sun
The Iowa Gambling Task (IGT) is a common paradigm used to study the interactions between emotions... more The Iowa Gambling Task (IGT) is a common paradigm used to study the interactions between emotions and decision making, yet little consensus exists on the cognitive process determining participants' decisions, what affects them, and how these processes interact with each other. A novel conceptual framework is proposed according to which behavior in the IGT reflects a balance between two dissociable processes; a cognitively demanding process that tracks each option's long-term payoff, and a lower-level, automatic process that is primarily sensitive to loss frequency and magnitude.
Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert ... more Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert influence on behavior, but some findings and replications of the original studies challenged this view. We investigated this topic by carrying out an experiment with the Iowa Gambling Task (IGT), where a dissociation procedure was adopted to successfully isolate possible implicit components. After a typical interaction with the IGT, participants performed a ''blind'' card selection phase without receiving any feedback. Half of them were instructed to continue choosing as they did before, the other half was told that good card decks turned bad, and vice versa, so that explicit knowledge was necessary to overcome the previously learned deck-outcome associations. The results confirmed the existence of early acquired implicit biases, confirming that previously experienced emotional events may covertly affect subsequent behavior.
The roles of prefrontal and anterior cingulate cortices have been widely studied, yet little is k... more The roles of prefrontal and anterior cingulate cortices have been widely studied, yet little is known on how they interact to enable complex cognitive abilities. We investigated this issue in a complex yet well defined symbolic paradigm: algebraic problem solving. In our experimental problems, the demands for retrieving arithmetic facts and maintaining intermediate problem representations were manipulated separately. An analysis of functional brain images acquired while participants were solving the problems confirmed that prefrontal regions were affected by the retrieval of arithmetic facts, but only scarcely by the need to manipulate intermediate forms of the equations, hinting at a specific role in memory retrieval. Hemodynamic activity in the dorsal cingulate, on the contrary, increased monotonically as more information processing steps had to be taken, independent of their nature. This pattern was essentially mimicked in the caudate nucleus, suggesting a related functional role in the control of cognitive actions. We also implemented a computational model within the ACT-R cognitive architecture, which was able to reproduce both the behavioral data and the time course of the hemodynamic activity in a number of relevant ROIs. Therefore, imaging results and computer simulation provide evidence that symbolic cognition can be explained by the functional interaction of medial structures supporting control and serial execution, and prefrontal cortices engaged in the on-line retrieval of specific relevant information.
The Lemonade Game is a three-player game in which players have to pick locations on a circular bo... more The Lemonade Game is a three-player game in which players have to pick locations on a circular board, which are as far away as possible from those chosen independently by other players. Players may observe other player's moves and infer their strategies. The game was examined using a competition of cognitively motivated agents, which inherit properties of human memory and decision-making, and simplistic, yet effective agents. We argue that metacognition constitutes the unique attribute that allows sophisticated agents to adapt to unforeseen conditions, cooperators and competitors.
The methodologies of cognitive architectures and functional magnetic resonance imaging can mutual... more The methodologies of cognitive architectures and functional magnetic resonance imaging can mutually inform each other. For example, four modules of the ACT-R (adaptive control of thought -rational) cognitive architecture have been associated with four brain regions that are active in complex tasks. Activity in a lateral inferior prefrontal region reflects retrieval of information in a declarative module; activity in a posterior parietal region reflects changes to problem representations in an imaginal module; activity in the anterior cingulate cortex reflects the updates of control information in a goal module; and activity in the caudate nucleus reflects execution of productions in a procedural module. Differential patterns of activation in such central regions can reveal the time course of different components of complex cognition.
One of the open issues in developing large-scale computational models of the brain is how the tra... more 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 stimulusresponse 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 smallsize brain circuits and high-level characterizations of complex cognition, such as cognitive architectures.
Intelligent and versatile behavior requires the capability of adapting to novel and unanticipated... more Intelligent and versatile behavior requires the capability of adapting to novel and unanticipated situations. When facing novel and unexpected tasks, a fast and general solution consists in creating new declarative task representations, and subsequently acting upon them. Although this mechanism seems straightforward in general terms, it poses significant difficulties to be implemented in a biological model, and the exact neural substrates of this process are still unknown. Based on the analysis of two different computational models, we hypothesized that the brain circuit for interpreting instructions would comprise the aPFC (holding dependencies among specialized cortical areas) and the basal ganglia (orchestrating the exchange of information among regions). To verify this hypothesis, we designed and ran an fMRI experiment where participants had to perform changing tasks that consisted of different combinations of atomic cognitive operations. Both models and experimental data suggest that the aPFC is critical in representing abstract knowledge that reflects planned cognitive operations. This is consistent with the late appearance of aPFC in the evolution of the human brain, and its role in enabling human intelligence and culture. On the other hand, results and simulations show that the effect of this cortical region is made possible by the contribution of the basal ganglia circuit, which works as a general-purpose interpreter of declarative knowledge.
International Journal of Machine Consciousness, 2010
ABSTRACT Recent years have seen a gradual convergence of seemingly distant research fields over a... more ABSTRACT Recent years have seen a gradual convergence of seemingly distant research fields over a single goal: understanding and replicating biological intelligence in artifacts. This work presents a general overview on the origin, the state-of-the-art, scientific challenges and the future of Biologically Inspired Cognitive Architecture (BICA) research. Our perspective decomposes the field into the four principal semantic components associated with the BICA challenge that together call for an integration of efforts of researchers across disciplines. Areas and directions of study where new integrated efforts will be primarily needed are summarized.
The basal ganglia play a central role in cognition and are involved in such general functions as ... more The basal ganglia play a central role in cognition and are involved in such general functions as action selection and reinforcement learning. Here, we present a model exploring the hypothesis that the basal ganglia implement a conditional information-routing system. The system directs the transmission of cortical signals between pairs of regions by manipulating separately the selection of sources and destinations of information transfers. We suggest that such a mechanism provides an account for several cognitive functions of the basal ganglia. 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 transferred cortical representations in the striatum. We discuss how the model is related to production systems and cognitive architectures. A series of simulations is presented to illustrate how the model can perform simple stimulus-response tasks, develop automatic behaviors, and provide an account of impairments in Parkinson's and Huntington's diseases.
A new interpretation for the results of several experiments carried out using the Gambling Task p... more A new interpretation for the results of several experiments carried out using the Gambling Task paradigm is presented that differs from that put forward by . While Damasio grounds his analysis on the somatic markers hypothesis, we propose a perspective based on the functional integration of emotion with memory that is sympathetic with the view of the prefrontal cortex endorsed by . Our interpretation is supported by the development of a computational model implemented in the ACT-R cognitive architecture. The model highlights some limitations of the architecture that arise when dealing with situations charged with emotional significance. In particular, the model-when developed according to the standard ACT-R theory-produces a perseverating behavior that replicates the performance exhibited by participants with lesions in the orbitofrontal cortex. An adjustment to the ACT-R equations describing the activation of elements in declarative memory is suggested that allows modeling the performance of both normal controls and orbitofrontal patients.
Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert ... more Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert influence on behavior, but some findings and replications of the original studies challenged this view. We investigated this topic by carrying out an experiment with the Iowa Gambling Task (IGT), where a dissociation procedure was adopted to successfully isolate possible implicit components. After a typical interaction with the IGT, participants performed a ''blind'' card selection phase without receiving any feedback. Half of them were instructed to continue choosing as they did before, the other half was told that good card decks turned bad, and vice versa, so that explicit knowledge was necessary to overcome the previously learned deck-outcome associations. The results confirmed the existence of early acquired implicit biases, confirming that previously experienced emotional events may covertly affect subsequent behavior.
Abstract In the paper we propose a revision of the Somatic Maker Hy- pothesis (henceforth SMH: Da... more Abstract In the paper we propose a revision of the Somatic Maker Hy- pothesis (henceforth SMH: Damasio, 1994). Most of the cor- roboration for this theory, as well as some contrary results, come,from an experimental decision making,paradigm,known as the Iowa Gambling,Task. We analyze the different con- stituents of the SMH and argue that the discrepancy between the theory predictions and the experiments,reported in the lit- erature can be explained by modifying,the theory to include a different functional role of somatic markers in high-order cog- nition. This revised version is in turn related to a different func- tional interpretation of the orbitofrontal cortex. Within this new,framework,we describe a detailed computational,model that is able to reproduce the original experimental data, and we show,that it can also account for the behavior deriving from other neuropsychological impairments.
The cognitive modeling of human behavior: Why a model is (sometimes) better than 10,000 words Act... more The cognitive modeling of human behavior: Why a model is (sometimes) better than 10,000 words Action editor: Ron Sun
The Iowa Gambling Task (IGT) is a common paradigm used to study the interactions between emotions... more The Iowa Gambling Task (IGT) is a common paradigm used to study the interactions between emotions and decision making, yet little consensus exists on the cognitive process determining participants' decisions, what affects them, and how these processes interact with each other. A novel conceptual framework is proposed according to which behavior in the IGT reflects a balance between two dissociable processes; a cognitively demanding process that tracks each option's long-term payoff, and a lower-level, automatic process that is primarily sensitive to loss frequency and magnitude.
Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert ... more Many authors have endorsed the hypothesis that previous emotional experiences may exert a covert influence on behavior, but some findings and replications of the original studies challenged this view. We investigated this topic by carrying out an experiment with the Iowa Gambling Task (IGT), where a dissociation procedure was adopted to successfully isolate possible implicit components. After a typical interaction with the IGT, participants performed a ''blind'' card selection phase without receiving any feedback. Half of them were instructed to continue choosing as they did before, the other half was told that good card decks turned bad, and vice versa, so that explicit knowledge was necessary to overcome the previously learned deck-outcome associations. The results confirmed the existence of early acquired implicit biases, confirming that previously experienced emotional events may covertly affect subsequent behavior.
The roles of prefrontal and anterior cingulate cortices have been widely studied, yet little is k... more The roles of prefrontal and anterior cingulate cortices have been widely studied, yet little is known on how they interact to enable complex cognitive abilities. We investigated this issue in a complex yet well defined symbolic paradigm: algebraic problem solving. In our experimental problems, the demands for retrieving arithmetic facts and maintaining intermediate problem representations were manipulated separately. An analysis of functional brain images acquired while participants were solving the problems confirmed that prefrontal regions were affected by the retrieval of arithmetic facts, but only scarcely by the need to manipulate intermediate forms of the equations, hinting at a specific role in memory retrieval. Hemodynamic activity in the dorsal cingulate, on the contrary, increased monotonically as more information processing steps had to be taken, independent of their nature. This pattern was essentially mimicked in the caudate nucleus, suggesting a related functional role in the control of cognitive actions. We also implemented a computational model within the ACT-R cognitive architecture, which was able to reproduce both the behavioral data and the time course of the hemodynamic activity in a number of relevant ROIs. Therefore, imaging results and computer simulation provide evidence that symbolic cognition can be explained by the functional interaction of medial structures supporting control and serial execution, and prefrontal cortices engaged in the on-line retrieval of specific relevant information.
The Lemonade Game is a three-player game in which players have to pick locations on a circular bo... more The Lemonade Game is a three-player game in which players have to pick locations on a circular board, which are as far away as possible from those chosen independently by other players. Players may observe other player's moves and infer their strategies. The game was examined using a competition of cognitively motivated agents, which inherit properties of human memory and decision-making, and simplistic, yet effective agents. We argue that metacognition constitutes the unique attribute that allows sophisticated agents to adapt to unforeseen conditions, cooperators and competitors.
The methodologies of cognitive architectures and functional magnetic resonance imaging can mutual... more The methodologies of cognitive architectures and functional magnetic resonance imaging can mutually inform each other. For example, four modules of the ACT-R (adaptive control of thought -rational) cognitive architecture have been associated with four brain regions that are active in complex tasks. Activity in a lateral inferior prefrontal region reflects retrieval of information in a declarative module; activity in a posterior parietal region reflects changes to problem representations in an imaginal module; activity in the anterior cingulate cortex reflects the updates of control information in a goal module; and activity in the caudate nucleus reflects execution of productions in a procedural module. Differential patterns of activation in such central regions can reveal the time course of different components of complex cognition.
One of the open issues in developing large-scale computational models of the brain is how the tra... more 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 stimulusresponse 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 smallsize brain circuits and high-level characterizations of complex cognition, such as cognitive architectures.
Intelligent and versatile behavior requires the capability of adapting to novel and unanticipated... more Intelligent and versatile behavior requires the capability of adapting to novel and unanticipated situations. When facing novel and unexpected tasks, a fast and general solution consists in creating new declarative task representations, and subsequently acting upon them. Although this mechanism seems straightforward in general terms, it poses significant difficulties to be implemented in a biological model, and the exact neural substrates of this process are still unknown. Based on the analysis of two different computational models, we hypothesized that the brain circuit for interpreting instructions would comprise the aPFC (holding dependencies among specialized cortical areas) and the basal ganglia (orchestrating the exchange of information among regions). To verify this hypothesis, we designed and ran an fMRI experiment where participants had to perform changing tasks that consisted of different combinations of atomic cognitive operations. Both models and experimental data suggest that the aPFC is critical in representing abstract knowledge that reflects planned cognitive operations. This is consistent with the late appearance of aPFC in the evolution of the human brain, and its role in enabling human intelligence and culture. On the other hand, results and simulations show that the effect of this cortical region is made possible by the contribution of the basal ganglia circuit, which works as a general-purpose interpreter of declarative knowledge.
International Journal of Machine Consciousness, 2010
ABSTRACT Recent years have seen a gradual convergence of seemingly distant research fields over a... more ABSTRACT Recent years have seen a gradual convergence of seemingly distant research fields over a single goal: understanding and replicating biological intelligence in artifacts. This work presents a general overview on the origin, the state-of-the-art, scientific challenges and the future of Biologically Inspired Cognitive Architecture (BICA) research. Our perspective decomposes the field into the four principal semantic components associated with the BICA challenge that together call for an integration of efforts of researchers across disciplines. Areas and directions of study where new integrated efforts will be primarily needed are summarized.
The basal ganglia play a central role in cognition and are involved in such general functions as ... more The basal ganglia play a central role in cognition and are involved in such general functions as action selection and reinforcement learning. Here, we present a model exploring the hypothesis that the basal ganglia implement a conditional information-routing system. The system directs the transmission of cortical signals between pairs of regions by manipulating separately the selection of sources and destinations of information transfers. We suggest that such a mechanism provides an account for several cognitive functions of the basal ganglia. 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 transferred cortical representations in the striatum. We discuss how the model is related to production systems and cognitive architectures. A series of simulations is presented to illustrate how the model can perform simple stimulus-response tasks, develop automatic behaviors, and provide an account of impairments in Parkinson's and Huntington's diseases.
Uploads
Papers by Andrea Stocco