332,646 research outputs found

    Perceived Diversity of Complex Environmental Systems: Multidimensional Measurement and Synthetic Indicators

    Get PDF
    The general attitude towards the sustainable management of environmental resources is evolving towards the implementation of ‘participatory’ (as opposed to the classical ‘command and control’) and, especially at local scale, ‘bottom up’ (as opposed to the classical ‘top down’) approaches. This progress pushes a major interest in the development and application of methodologies able to ‘discover’ and ‘measure’ how environmental systems tend to be perceived by the different Stakeholders. Due to the ‘nature’ of the investigated systems, often too ‘complex’ to be treated through a classical deterministic approach, as typical for ‘hard’ physical/mathematical sciences, any ‘measurement’ has necessarily to be multidimensional. In the present report an approach, more typical of ‘soft’ social sciences, is presented and applied to the analysis of the sustainable management of water resources in seven Southern and Eastern Mediterranean Watersheds. The methodology is based on the development and analysis (explorative factor analysis, multidimensional scaling) of a questionnaire and is aimed at the ‘discovery’ and ‘measurement’ of a latent multidimensional ‘underlying structure’ (‘conceptual map’). It is the opinion of the authors, that the identification of a set of ‘consistent’, ‘independent’, ‘bottom up’ and ‘shared’ synthetic indicators (aggregated indices) could be strongly facilitated by the interpretation of the dimensions of the emerging ‘underlying structure’.Participative Approach, Cognitive Map, Factor Analysis, Indicators of Sustainability, Sustainable Water, Management

    A Matched Filter Hypothesis for Cognitive Control

    Get PDF
    The prefrontal cortex exerts top-down influences on several aspects of higher-order cognition by functioning as a filtering mechanism that biases bottom-up sensory information toward a response that is optimal in context. However, research also indicates that not all aspects of complex cognition benefit from prefrontal regulation. Here we review and synthesize this research with an emphasis on the domains of learning and creative cognition, and outline how the appropriate level of cognitive control in a given situation can vary depending on the organism's goals and the characteristics of the given task. We offer a Matched Filter Hypothesis for cognitive control, which proposes that the optimal level of cognitive control is task-dependent, with high levels of cognitive control best suited to tasks that are explicit, rule-based, verbal or abstract, and can be accomplished given the capacity limits of working memory and with low levels of cognitive control best suited to tasks that are implicit, reward-based, non-verbal or intuitive, and which can be accomplished irrespective of working memory limitations. Our approach promotes a view of cognitive control as a tool adapted to a subset of common challenges, rather than an all-purpose optimization system suited to every problem the organism might encounter

    Expectation of reward differentially modulates executive inhibition

    Get PDF
    Abstract: Background: Inhibitory control, a key modulatory component of cognition guiding strategy and behaviour, can be affected by diverse contingencies. We explore here the effect of expectation of reward over behavioural adjustment in a Stop Signal Task modulated by reward. We hypothesize that cognitive control is modulated by different expectation of the reward. Methods: Participants were allocated to two groups differing in their degree of knowledge in what to expect from rewards. Expected Specific Reward participants (N = 21) were informed of the different monetary feedbacks they would receive after each successful inhibition. Unexpected Reward participants (N = 24) were only told that they would receive monetary reward after correct inhibitory trials, but not the amounts or differences. Results: Our results confirmed previous observations demonstrating a “kick-start effect” where a high reward feedback at the beginning of the task increases response inhibition. The Expected Specific Reward condition seems also to improve inhibitory control -as measured by the stop signal reaction time (SSRT)-, compared to the Unexpected Reward group. Conclusions: Knowledge of reward magnitudes seems to play a role in cognitive control irrespective of feedback magnitude. The manipulation of reward expectation appears to trigger different strategies for cognitive control, inducing a bottom-up effect of external cues, or a top-down effect given by the anticipation of incoming rewards. This is an early exploration to unearth possible higher order modulators - expectation and motivation- of cognitive control. This approach aims to gain insight into diverse psychopathological conditions related to impulsivity and altered reward systems such as Attention Deficit Hyperactive Disorder (ADHD), personality disorders, substance abuse, pathological gambling and cognitive aspects of Parkinson Disease

    Top-down and bottom-up contributions to memory performance in OCD: A multilevel meta-analysis with clinical implications

    Get PDF
    Despite extensive coverage of a relationship between memory performance and executive function in the obsessive-compulsive disorder (OCD) literature, the relative contributions of specific aspects of executive control have remained elusive. We, therefore, extend our previous multilevel meta-analysis (Persson et al., 2021), where demand on executive function was the most significant determinant of memory deficits in OCD, and provide a finer-grained analysis of executive control via a segregation into top-down (attentional control, maintenance and updating, planning) and bottom-up (perceptual integration, perceptual salience) contributions. Our multilevel meta-analytic approach allowed us to accommodate the interdependency of 255 effect sizes from 131 studies, totaling 4,101 OCD patients. Results revealed that maintenance and updating (top-down) and perceptual integration (bottom-up) predicted memory performance generally, and specifically in those with clinical OCD. Exploratory analyses suggested that this effect may be somewhat different among subclinical OCD groups; however, these findings should be considered with conceptual and analytical caveats in mind. We explain these results via deficient sensory (perceptual integration) and working memory (maintenance and updating) gating mechanisms and propose a model to accommodate their expression in OC symptoms. In conclusion, our meta-analysis has expanded understanding of cognitive performance in OCD and identifies the possibility of untapped cognitive targets for intervention

    Using confidence interval-based estimation of relevance to explore bottom-up and top-down determinants of problematic eating behavior in children and adolescents with obesity from a dual pathway perspective

    Get PDF
    Prevalence of overweight and obesity in children and adolescents is high, not only in Western countries but also in developing countries. Efforts to improve prevention and treatment programs are needed. Given their essential role in weight problems, knowledge of determinants of problematic eating behavior ('External Eating' and 'Emotional Eating') is crucial for intervention development. Inspired by Appelhans' Dual Process Theory of Eating Behavior, the present study evaluated the importance of top-down regulative capacities and bottom-up reactivity, using the CIBER approach. CIBER is an innovative statistical approach to test the importance of behavior determinants, based on confidence intervals, instead of significance testing of point estimates. Survey data on different aspects of executive functioning (as indices of regulative capacities: Inhibition, Cognitive Flexibility, Emotional Control, Initiation, Working Memory, Planning/Organizing, Organization of materials, and Monitoring) and reward sensitivity (as an index of reactivity) were collected in a large sample of children and adolescents (n = 572) with severe obesity (adjBMI > 180%). Results showed that Emotional Eating is determined by Emotional Control, while External Eating is determined by Reward Sensitivity. The finding that differential mechanisms underlie different aspects of problematic eating suggests the need for using tailored intervention techniques to address altered reactivity and weak regulative capacities

    An Experimental Test of the Effects of Sleep Deprivation on Approach Behavior

    Get PDF
    Emotion regulation and sleep have been identified as mechanisms that may be involved in the development and maintenance of many mental health disorders. However, there has been little research into the relation between sleep and emotion regulation. To address this gap in knowledge, a novel study was conducted. We hypothesized that sleep deprived individuals would demonstrate less approach behavior toward a negatively valenced stimulus, as well as increased self-reported avoidance, compared to a control group. To test this, a randomized controlled experiment using a behavioral measure of approach and a self-report measure of avoidance was conducted. Fifty-two healthy individuals ages 18-30 years old who did not meet criteria for any current mental health disorders were recruited. Participants were randomly assigned to a full night of sleep deprivation or normal sleep and completed a baseline and post-manipulation behavioral avoidance task (BAT) and self-report of avoidance behavior. Repeated measures ANOVAs demonstrated there were no significant effects of sleep deprivation on approach behaviors. However, self-reported avoidance increased for the sleep deprived participants. Results highlight a discrepancy between predicted and actual behavior, specifically, the effect of sleep deprivation on behavioral approach toward a specific stimulus compared to more resource-intensive cognitive and behavioral approaches found in daily life. This may guide future work investigating top-down and bottom-up processing of emotion regulation

    Executive control: an electrophysiological investigation of control processes

    Get PDF
    Everyday behaviour requires constant coordination and monitoring in order for our actions to be successful. Within cognitive science such coordination and monitoring of behaviour is termed ‘control’ and refers to a set of functions that serve to configure the mental system for performing specific acts. A system of cognitive control is thought to set high level goals and direct subordinate cognitive systems in order to accomplish those goals. This thesis utilises a cognitive electrophysiological approach to the study of executive control, addressing research questions concerning the mental processes that are modulated by executive control and the mechanisms underlying control-related processing adjustments. The first experimental chapter investigates the process of task switching. More specifically, how demanding is a proposed stage of endogenous task-set reconfiguration in terms of information processing? It was previously reported that the process of task-set reconfiguration constitutes a hard bottleneck delaying even the earliest processing stages (e.g. perceptual) (Oriet & Jolicoeur, 2003). Three experiments investigated this claim by manipulating stimulus contrast and RSI within an alternating runs task switching paradigm. Both RT results and measurements of P1 and N1 ERP component peak latency did not offer support to the claim that task-set reconfiguration delays perceptual processing. Experimental Chapters 3 and 4 used interference paradigms that are common within the study of executive control (e.g. Eriksen Flanker task and a Stroop task, respectively). Within such interference paradigms, separate stimulus dimensions (relevant and irrelevant) are manipulated, with RT being faster when both the relevant and irrelevant stimulus dimensions indicate the same response. This is termed the ‘congruency effect’ and is often attributed to a failure of selective attention, namely, an inability to ignore the irrelevant stimulus dimension. It has been demonstrated that such congruency effects are dependent upon task sequence with the effect being reduced (or absent) after an incongruent trial (Gratton et al., 1992). Such conflict adaptation effects are a popular measure of cognitive control processes. An influential model of cognitive control is the conflict monitoring model of Botvinick et al. (2001), with much evidence for this model being based on the conflict adaptation effect. Specifically, the model proposes that the ACC measures for the occurrence of response conflict within two response channels, and when detected, signals its occurrence to other brain regions (e.g. DLPFC) that are involved in implementing control. Such control may be implemented via a top-down biasing mechanisms of attention toward the task-relevant stimulus feature. Chapter 3 investigated the conflict adaptation effect within the Flanker task and examined, whether after the occurrence of conflict, attention is directed toward the task-relevant central target location. This was done by measuring P1 and N1 ERP component amplitudes. Although behavioural conflict adaptation effects were evident in overt behaviour, these were specific to response repetitions, consistent with a bottom-up priming account that excludes the necessity for a top-down control explanation (e.g. Mayr et al., 2003). In addition, P1 and N1 amplitude did not show any evidence of increased attentional focus toward the central target location after the occurrence of conflict. Chapter 4 investigated the conflict adaptation effect within a modified Stroop task, and again, examined whether after the detection of conflict, attention is directed toward the task relevant stimulus feature. This was done by measuring N170 amplitude - an ERP component proposed to index face processing - when a face stimulus served as the relevant and irrelevant stimulus dimension. Again, conflict adaptation effects were evident in overt behaviour, with this effect being driven by the occurrence of response conflict. Unlike the data from the Flanker task, the conflict adaptation effect within the Stroop task was specific to response alternations, and thus, a bottom-up priming account is not applicable in this instance. However, again the ERP results did not offer any evidence that the processing of the relevant stimulus dimension was enhanced after the occurrence of conflict. Implications of the present results are discussed in the context of executive control and in particular, in relation to models of task switching and models of conflict control

    Mental states as emergent properties : from walking to consciousness

    Get PDF
    In this article we propose a bottom-up approach to higher-level mental states, such as emotions, attention, intention, volition, or consciousness. The idea behind this bottom-up approach is that higher-level properties may arise as emergent properties, i.e., occur without requiring explicit implementation of the phenomenon under examination. Using a neural architecture that shows the abilities of autonomous agents, we want to come up with quantitative hypotheses concerning cognitive mechanisms, i.e., to come up with testable predictions concerning the underlying structure and functioning of an autonomous system that can be tested in a robot-control system. we do not want to build an artificial system that is, for example, conscious in the first place. on the contrary, we want to construct a system able to control behavior. only then will this system be used as a tool to test to what extent descriptions of mental phenomena used in psychology or philosophy of mind may be applied to such an artificial system. originally these phenomena are necessarily defined using verbal formulations that allow for interpreting them differently. a functional definition, in contrast, does not suffer from being ambiguous, because it can be expressed explicitly using mathematical formulations that can be tested, for example, in a quantitative simulation. it is important to note that we are not concerned with the “hard” problem of consciousness, i.e., the subjective aspect of mental phenomena. this approach is possible because, adopting a monist view, we assume that we can circumvent the “hard” problem without losing information concerning the possible function of these phenomena. in other words, we assume that phenomenality is an inherent property of both access consciousness and metacognition (or reflexive consciousness). following these arguments, we claim that our network does not only show emergent properties on the reactive level; it also shows that mental states, such as emotions, attention, intention, volition, or consciousness can be observed, too. concerning consciousness, we argue that properties assumed to partially constitute access consciousness are present in our network, including the property of global availability, which means that elements of the procedural memory can be addressed even if they do not belong to the current context. further expansions are discussed that may allow for the recognition of properties attributed to metacognition or reflexive consciousness

    An account of cognitive flexibility and inflexibility for a complex dynamic task

    Get PDF
    Problem solving involves adapting known problem solving methods and strategies to the task at hand (Schunn & Reder, 2001) and cognitive flexibility is considered to be “the human ability to adapt the cognitive processing strategies to face new and unexpected conditions of the environment” (Cañas et al., 2005, p. 95). This work presents an ACT-R 6.0 model of complex problem solving behavior for the dynamic microworld game FireChief (Omodei & Wearing, 1995) that models the performance of participants predisposed to behave either more or less flexibly based on the nature of previous training on the task (Cañas et al., 2005). The model exhibits a greater or lesser degree of cognitive inflexibility in problem solving strategy choice reflecting variations in task training. The model provides an explanation of dynamic task performance compatible with the Competing Strategies paradigm (Taatgen et al., 2006) by creating a second layer of strategy competition that renders it more flexible with respect to strategy learning, and provides an explanation of cognitive inflexibility based on reward mechanism

    Rehabilitative devices for a top-down approach

    Get PDF
    In recent years, neurorehabilitation has moved from a "bottom-up" to a "top down" approach. This change has also involved the technological devices developed for motor and cognitive rehabilitation. It implies that during a task or during therapeutic exercises, new "top-down" approaches are being used to stimulate the brain in a more direct way to elicit plasticity-mediated motor re-learning. This is opposed to "Bottom up" approaches, which act at the physical level and attempt to bring about changes at the level of the central neural system. Areas covered: In the present unsystematic review, we present the most promising innovative technological devices that can effectively support rehabilitation based on a top-down approach, according to the most recent neuroscientific and neurocognitive findings. In particular, we explore if and how the use of new technological devices comprising serious exergames, virtual reality, robots, brain computer interfaces, rhythmic music and biofeedback devices might provide a top-down based approach. Expert commentary: Motor and cognitive systems are strongly harnessed in humans and thus cannot be separated in neurorehabilitation. Recently developed technologies in motor-cognitive rehabilitation might have a greater positive effect than conventional therapies
    • 

    corecore