The Vegetative State (VS) is characterized by the absence of awareness of self or the environment and preserved autonomic functions. The diagnosis relies critically on the lack of consistent signs of purposeful behavior in response to external stimulation. Yet, given that patients with disorders of consciousness often exhibit fragmented movement patterns, voluntary actions may go unnoticed. Here we designed a simple motor paradigm that could potentially detect residual conscious awareness in VS patients with mild to severe brain damage by examining (...) the neural correlates of motor preparation in response to verbal commands. Twenty-four patients who met the diagnostic criteria for VS were recruited for this study. Eleven of these patients showing preserved auditory evoked potentials underwent functional magnetic resonance imaging (fMRI) to test for basic speech processing. Five of these patients, who showed word related activity, were included in a second fMRI study aimed at detecting functional changes in premotor cortex elicited by specific verbal instructions to move either their left or their right hand. Despite the lack of overt muscle activity, two patients out of five activated the dorsal premotor cortex contralateral to the instructed hand, consistent with movement preparation. Given that movement preparation in response to a motor command is a sign of purposeful behavior, our results are consistent with residual conscious awareness in these patients. We believe that the identification of positive results with fMRI using this simple task, may complement the clinical assessment by helping attain a more precise diagnosis in patients with disorders of consciousness. (shrink)
For the authors' responses to comments similar to those expressed here by Balsam & Drew, please see: M. Domjan, B. Cusato, & R. Villarreal (2000). Extensions, elaborations, and explanations of the role of evolution and learning in the control of social behavior. BBS 23(2):269–82. [Authors' Response to first round of commentary.].
The conceptual and investigative tools for the analysis of social behavior can be expanded by integrating biological theory, control systems theory, and Pavlovian conditioning. Biological theory has focused on the costs and benefits of social behavior from ecological and evolutionary perspectives. In contrast, control systems theory is concerned with how machines achieve a particular goal or purpose. The accurate operation of a system often requires feed-forward mechanisms that adjust system performance in anticipation of future inputs. Pavlovian conditioning is ideally suited (...) to subserve this function in behavioral systems. Pavlovian mechanisms have been demonstrated in various aspects of sexual behavior, maternal lactation, and infant suckling. Pavlovian conditioning of agonistic behavior has been also reported, and Pavlovian processes may likewise be involved in social play and social grooming. Several further lines of evidence indicate that Pavlovian conditioning can increase the efficiency and effectiveness of social interactions, thereby improving their cost/benefit ratio. We extend Pavlovian concepts beyond the traditional domain of discrete secretory and other physiological reflexes to complex real-world behavioral interactions and apply abstract laboratory analyses of the mechanisms of associative learning to the daily challenges animals face as they interact with one another in their natural environments. Key Words: aggression; biological theory; control theory; feed-forward mechanisms; learning theory; nursing and lactation; Pavlovian conditioning; sexual behavior; social behavior; social grooming; social play. (shrink)
Reactions to the target article included requests for extensions and elaborations of the schema we proposed and discussions of apparent shortcomings of our approach. In general, we welcome suggestions for extension of the schema to additional kinds of social behavior and to forms of learning other than Pavlovian conditioning. Many of the requested elaborations of the schema are consistent with our approach, but some may limit its generality. Many of the apparent shortcomings that commentators discussed do not seem problematic. Our (...) schema encourages a broad view of the behavioral consequences of Pavlovian conditioning – including learned modifications of responding to the unconditioned stimulus. Costs and benefits addressed by our schema are the long-range reproductive consequences of learning – not the immediate reinforcing consequences of particular conditioned responses. Our approach allows the evolution of learning to yield maladaptive behavior and can be extended to characterize dynamic social interactions. We clarify that ours is not a homeostatic model involving ideal set points, and we clarify and defend our application of Pavlovian concepts to the analysis of social play. (shrink)
Knowledge systems theory, in our view, tends to obscure rather than illuminate an understanding of the fundamentals of knowledge processes in society. This tendency occurs primarily because both the theory, and the methodologies that are derived from it, fail to recognize that knowledge processes are social processes, and thereby that knowledge itself has to be envisaged as a social construction. As a result of this omission, knowledge systems theory and methodology can only deal poorly with issues of power and social (...) conflict, and, at the same time, tend to make use of several inappropriate teleological and reifying notions. According to our view, the understanding of knowledge processes will benefit greatly from a more actor-oriented perspective. In such an approach, emphasis is accorded to human agency and the concept of multiple knowledge networks. Central purposes of actor-oriented methodologies then, are to clarify how actors attempt to create space for their own ‘projects’ and to determine which elements contribute to or impede the successful creation of such space for maneuver. (shrink)
This paper presents a computational model of the way humans inductively identify and aggregate concepts from the low-level stimuli they are exposed to. Based on the idea that humans tend to select the simplest structures, it implements a dynamic hierarchical chunking mechanism in which the decision whether to create a new chunk is based on an information-theoretic criterion, the Minimum Description Length (MDL) principle. We present theoretical justifications for this approach together with results of an experiment in which participants, exposed (...) to meaningless symbols, have been implicitly encouraged to create high-level concepts by grouping them. Results show that the designed model, called hereafter MDLChunker, makes precise quantitative predictions both on the kind of chunks created by the participants and also on the moment at which these creations occur. They suggest that the simplicity principle used to design MDLChunker is particularly efficient to model chunking mechanisms. The main interest of this model over existing ones is that it does not require any adjustable parameter. (shrink)
Domjan, Cusato & Villarreal's target article is reviewed in the context of historical difficulty for learning studies in discriminating between learned and unlearned components of behavior. The research surveyed in the target article meets the criterion of differentiating between some learned and the unlearned aspects of social behavior, with Pavlovian conditioning shown repeatedly as a route by which reproductive and aggressive behavior is modulated.
Este artículo desarrolla algunos aspectos relativos a la mega-minería en tanto modelo biopolítico, a partir del marco regulatorio sancionado a comienzos de los 90 en la región. Focaliza para ello en dos macro-fenómenos que se verifican en su acelerada implantación: la desestatalización del territorio y la desterritorialización del Estado. A partir de este marco se propone señalar ciertas estrategias desplegadas por los dispositivos hegemónicos que vienen procurando su legitimación, y destacar un conjunto de consecuencias que de ellas se derivan para (...) la condición de existencia de subjetividades y cuerpos que distingue al extractivismo mega-minero: el vivir en la corteza. (shrink)
La presente investigación aborda el estudio de las transformaciones producidas en el paisaje del poblado de Puerto Morelos, Quintana Roo, por la incorporación de la actividad turística en la vida cotidiana de sus pobladores. A medida que los objetos, usos y el lenguaje del turismo se incorporan a las costumbres, tradiciones, relaciones sociales y estilos de vida de la población; los espacios de vida -laboral, vecinal, doméstico y de ocio- adquieren características físicas poco tradicionales y formas excluyentes de aprovechamiento que (...) contribuyen a configurar y fortalecer paisajes funcionales al capital turístico. La propiedad privada y el mercado de tierras, las políticas para la conservación de los recursos naturales, la deslocalización empresarial, la imagen turística y las oleadas migratorias son factores que han permitido la reorganización de los espacios de vida y, por consiguiente, la configuración de diversos paisajes turísticos a lo largo de la costa. (shrink)
Con el modelo de bienestar, los sectores económicos tuvieron un crecimiento sustantivo en México. Con el cambio del modelo económico, el sector servicios, sobre todo, el turismo, se ha consolidado como una actividad que homogeniza y funcionaliza el paisaje para facilitar la apropiación de los recursos naturales y culturales de las comunidades rurales para la expansión de la economía de libre mercado, con el objetivo de que permanezca el modo de producción y reproducción vinculado al capital, con lo que se (...) contradice la sustentabilidad de la actividad. Para el análisis de dicha situación y sus implicaciones, se propone el uso de la estrategia materialista cultural (Harris, 1982) como base teórico-metodológica general fortalecida con las propuestas de Sauer (1925) para el conocimiento del paisaje natural y cultural, y de Cordero (2004) para el conocimiento de las formas de apropiación de la naturaleza y la cultura que utiliza la expansión capitalista. Con esta propuesta se espera coadyuvar en la identificación del proceso de apropiación, homogenización y funcionalización, vinculado al turismo. (shrink)
We study experimentally a coordination game with N heterogeneous individuals under different information treatments. We explore the effects of information on the emergence of Pareto-efficient outcomes, by means of a gradual decrease of the information content provided to the players in successive experiments. We observe that successful coordination is possible with private information alone, although not on a Pareto-optimal equilibrium. Reinforcement-based learning models reproduce the qualitative trends of the experimental results.