385 research outputs found

    The role of error processing in the contextual interference effect during the training of perceptual-cognitive skills

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    The contextual interference (CI) effect refers to the learning benefits that occur from a random compared to blocked practice order. In this paper, the cognitive effort explanation for the CI effect was examined by investigating the role of error processing. In two experiments, a perceptual-cognitive task was used in which participants anticipated three different tennis skills across a pre-test, three practice sessions, and retention test. During practice, the skills were presented in either a random or blocked practice order. In Experiment 1, cognitive effort was examined using a probe reaction time task. In Experiment 2, cognitive effort was manipulated for two groups by inserting a cognitively demanding secondary task into the inter-trial interval. The CI effect was found in both experiments as the random groups displayed superior learning in the retention test compared to the blocked groups. Cognitive effort during practice was greater in random compared to blocked practice groups in Experiment 1. In Experiment 2, greater decrements in secondary task performance following an error were reported for the random group when compared to the blocked group. The suggestion is that not only the frequent switching of tasks in randomized orders causes increased cognitive effort and the CI effect, but it is also error processing in combination with task switching. Findings extend the cognitive effort explanation for the CI effect and propose an alternative hypothesis highlighting the role of error processing

    Integrating explicit contextual priors and kinematic information during anticipation

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    © 2020 The Author(s). We examined the interaction between explicit contextual priors and kinematic information during anticipation in soccer. We employed a video-based anticipation task where skilled soccer players had to predict the direction of the imminent actions of an attacking opponent in possession of the ball. The players performed the task both with and without explicit contextual priors pertaining to the opponent’s action tendencies. The strength of the opponent’s action tendencies was altered in order to manipulate the reliability of contextual priors (low vs. high). Moreover, the reliability of kinematic information (low vs. high) was manipulated using the temporal occlusion paradigm. The explicit provision of contextual priors biased anticipation towards the most likely direction, given the opponent’s action tendencies, and resulted in enhanced performance. This effect was greater under conditions where the reliability of kinematic information was low rather than high. When the reliability of kinematic information was high, the players used explicit contextual priors of high, but not low, reliability to inform their judgements. Findings suggest that athletes employ reliability-based strategies when integrating contextual priors with kinematic information during anticipation. The impact of explicit contextual priors is dependent on the reliability both of the priors and the evolving kinematic information

    Judgement utility modulates the use of explicit contextual priors and visual information during anticipation

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    Objectives: We examined the impact of judgement utility on the use of explicit contextual priors and visual information during action anticipation in soccer. Design: We employed a repeated measures design, in which expert soccer players had to perform a video-based anticipation task under various conditions. Methods: The task required the players to predict the direction (left or right) of an oncoming opponent’s imminent actions. Performance and verbal reports of thoughts from players were compared across three conditions. In two of the conditions, contextual priors pertaining to the opponent’s action tendencies (dribble = 70%; pass = 30%) were explicitly provided. In one of these experimental conditions, players were told that an incorrect ‘right’ response would result in conceding a goal, which created imbalanced judgement utility (left = high utility; right = low utility). In the third control condition, no explicit contextual priors or additional instructions were provided. Results: The explicit provision of contextual priors changed players’ processing priorities, biased their anticipatory judgements in accordance with the opponent’s action tendencies, and enhanced anticipation performance. These effects were suppressed under conditions in which the explicit contextual priors were accompanied by imbalanced judgement utility. Under these conditions, the players were more concerned about the consequences of their judgements and were more inclined to opt for the direction with the higher utility. Conclusions: It appears that judgement utility disrupts the integration of contextual priors and visual information, which results in decreased impact of explicit contextual priors during action anticipation

    The use of contextual priors and visual information during anticipation in sport: Toward a Bayesian integration framework

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    © 2020 The Author(s). Expert performance across a range of domains is underpinned by superior perceptual-cognitive skills. Over the last five decades, researchers have provided evidence that experts can identify and interpret opponent kinematics more effectively than their less experienced counterparts. More recently, researchers have demonstrated that experts also use non-kinematic information, in this paper termed contextual priors, to inform their predictive judgments. While the body of literature in this area continues to grow exponentially, researchers have yet to develop an overarching theoretical framework that can predict and explain anticipatory behaviour and provide empirically testable hypotheses to guide future work. In this paper, we propose that researchers interested in anticipation in sport could adopt a Bayesian model for probabilistic inference as an overarching framework. We argue that athletes employ Bayesian reliability-based strategies in order to integrate contextual priors with evolving kinematic information during anticipation. We offer an insight into Bayesian theory and demonstrate how contemporary literature in sport psychology fits within this framework. We hope that the paper encourages researchers to engage with the Bayesian literature in order to provide greater insight into expert athletes’ assimilation of various sources of information when anticipating the actions of others in complex and dynamic environments

    Delegating Quantum Computation in the Quantum Random Oracle Model

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    A delegation scheme allows a computationally weak client to use a server's resources to help it evaluate a complex circuit without leaking any information about the input (other than its length) to the server. In this paper, we consider delegation schemes for quantum circuits, where we try to minimize the quantum operations needed by the client. We construct a new scheme for delegating a large circuit family, which we call "C+P circuits". "C+P" circuits are the circuits composed of Toffoli gates and diagonal gates. Our scheme is non-interactive, requires very little quantum computation from the client (proportional to input length but independent of the circuit size), and can be proved secure in the quantum random oracle model, without relying on additional assumptions, such as the existence of fully homomorphic encryption. In practice the random oracle can be replaced by an appropriate hash function or block cipher, for example, SHA-3, AES. This protocol allows a client to delegate the most expensive part of some quantum algorithms, for example, Shor's algorithm. The previous protocols that are powerful enough to delegate Shor's algorithm require either many rounds of interactions or the existence of FHE. The protocol requires asymptotically fewer quantum gates on the client side compared to running Shor's algorithm locally. To hide the inputs, our scheme uses an encoding that maps one input qubit to multiple qubits. We then provide a novel generalization of classical garbled circuits ("reversible garbled circuits") to allow the computation of Toffoli circuits on this encoding. We also give a technique that can support the computation of phase gates on this encoding. To prove the security of this protocol, we study key dependent message(KDM) security in the quantum random oracle model. KDM security was not previously studied in quantum settings.Comment: 41 pages, 1 figures. Update to be consistent with the proceeding versio

    Skill-based differences in the impact of opponent exposure during anticipation: the role of context-environment dependency

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    Data availability statement: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.Copyright © 2023 Gredin, Thomas, Broadbent, Fawver and Williams. Introduction: We examined skilled-based differences in the impact of exposure to an opponent with action tendencies that were either independent of, dependent on, or both independent of and dependent on evolving environmental information during anticipation. Methods: A video-based two-vs.-two soccer task was employed, where 14 expert and 14 novice soccer players had to predict an attacking opponent's imminent actions, before and after exposure to the preceding actions of the opponent. Results: Anticipation accuracy, number of responses congruent with the opponent's action tendencies, response confidence, and visual dwell time on the opponent in possession increased following opponent exposure, both in experts and novices. When compared to novices, experts demonstrated higher anticipation accuracy, more congruent responses, and greater response confidence. Novices performed at their best when the opponent exhibited action tendencies that were independent of the environment, whereas experts demonstrated their highest performance when the opponent had action tendencies that were both independent of and dependent on unfolding environmental information. Discussion: Our findings provide novel insights into the role of context-environment dependency and support the notion that experts are superior to novices in detecting and utilizing opponents' action tendencies and integrating this information with unfolding environmental information during anticipation

    The melanoma-specific graded prognostic assessment does not adequately discriminate prognosis in a modern population with brain metastases from malignant melanoma

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    The melanoma-specific graded prognostic assessment (msGPA) assigns patients with brain metastases from malignant melanoma to 1 of 4 prognostic groups. It was largely derived using clinical data from patients treated in the era that preceded the development of newer therapies such as BRAF, MEK and immune checkpoint inhibitors. Therefore, its current relevance to patients diagnosed with brain metastases from malignant melanoma is unclear. This study is an external validation of the msGPA in two temporally distinct British populations.Performance of the msGPA was assessed in Cohort I (1997-2008, n=231) and Cohort II (2008-2013, n=162) using Kaplan-Meier methods and Harrell's c-index of concordance. Cox regression was used to explore additional factors that may have prognostic relevance.The msGPA does not perform well as a prognostic score outside of the derivation cohort, with suboptimal statistical calibration and discrimination, particularly in those patients with an intermediate prognosis. Extra-cerebral metastases, leptomeningeal disease, age and potential use of novel targeted agents after brain metastases are diagnosed, should be incorporated into future prognostic models.An improved prognostic score is required to underpin high-quality randomised controlled trials in an area with a wide disparity in clinical care

    Security Limitations of Classical-Client Delegated Quantum Computing

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    Secure delegated quantum computing allows a computationally weak client to outsource an arbitrary quantum computation to an untrusted quantum server in a privacy-preserving manner. One of the promising candidates to achieve classical delegation of quantum computation is classical-client remote state preparation (RSPCCRSP_{CC}), where a client remotely prepares a quantum state using a classical channel. However, the privacy loss incurred by employing RSPCCRSP_{CC} as a sub-module is unclear. In this work, we investigate this question using the Constructive Cryptography framework by Maurer and Renner (ICS'11). We first identify the goal of RSPCCRSP_{CC} as the construction of ideal RSP resources from classical channels and then reveal the security limitations of using RSPCCRSP_{CC}. First, we uncover a fundamental relationship between constructing ideal RSP resources (from classical channels) and the task of cloning quantum states. Any classically constructed ideal RSP resource must leak to the server the full classical description (possibly in an encoded form) of the generated quantum state, even if we target computational security only. As a consequence, we find that the realization of common RSP resources, without weakening their guarantees drastically, is impossible due to the no-cloning theorem. Second, the above result does not rule out that a specific RSPCCRSP_{CC} protocol can replace the quantum channel at least in some contexts, such as the Universal Blind Quantum Computing (UBQC) protocol of Broadbent et al. (FOCS '09). However, we show that the resulting UBQC protocol cannot maintain its proven composable security as soon as RSPCCRSP_{CC} is used as a subroutine. Third, we show that replacing the quantum channel of the above UBQC protocol by the RSPCCRSP_{CC} protocol QFactory of Cojocaru et al. (Asiacrypt '19), preserves the weaker, game-based, security of UBQC.Comment: 40 pages, 12 figure

    The interaction of gambling outcome and gambling harm-minimisation strategies for electronic gambling: the efficacy of computer generated self-appraisal messaging

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    It has been argued that generating pop-up messages during electronic gambling sessions, which cause a player to engage in self-appraisal of their gambling behaviour, instil greater control and awareness of behaviour (Monaghan, Computers in Human Behaviour, 25, 202–207, 2009). Consideration for the potential interaction between the messaging’s efficacy and gambling outcome (winning or losing) is lacking however. Thirty participants took part in a repeated-measures experiment where they gambled on the outcome of a computer-simulated gambling task. Outcome was manipulated by the experimenter to induce winning and losing streaks. Participants gambled at a significantly faster speed and a higher average stake size, which resulted in a greater betting intensity in the Loss condition compared to the Win condition. Computer generated self-appraisal messaging was then applied during the gambling session, which was able to significantly reduce the average speed of betting in the Loss condition only, demonstrating an interaction effect between computer generated messaging and gambling outcome
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