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"Concept Formation."
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Conceptual overlap among texts impedes comprehension monitoring
For decades, research on
metacomprehension
has demonstrated that many learners struggle to accurately discriminate their comprehension of texts. However, while reviews of experimental studies on relative metacomprehension accuracy have found average intra-individual correlations between predictions and performance of around .27 for adult readers, in some contexts even lower near-zero accuracy levels have been reported. One possible explanation for those strikingly low levels of accuracy is the high conceptual overlap between topics of the texts. To test this hypothesis, in the present work participants were randomly assigned to read one of two text sets that differed in their degree of conceptual overlap. Participants judged their understanding and completed an inference test for each topic. Across two studies, mean relative accuracy was found to match typical baseline levels for the low-overlap text sets and was significantly lower for the high-overlap text sets. Results suggest text similarity is an important factor impacting comprehension monitoring accuracy that may have contributed to the variable and sometimes inconsistent results reported in the metacomprehension literature.
Journal Article
Neural representations of confidence emerge from the process of decision formation during perceptual choices
Choice confidence represents the degree of belief that one's actions are likely to be correct or rewarding and plays a critical role in optimizing our decisions. Despite progress in understanding the neurobiology of human perceptual decision-making, little is known about the representation of confidence. Importantly, it remains unclear whether confidence forms an integral part of the decision process itself or represents a purely post-decisional signal. To address this issue we employed a paradigm whereby on some trials, prior to indicating their decision, participants could opt-out of the task for a small but certain reward. This manipulation captured participants' confidence on individual trials and allowed us to discriminate between electroencephalographic signals associated with certain-vs.-uncertain trials. Discrimination increased gradually and peaked well before participants indicated their choice. These signals exhibited a temporal profile consistent with a process of evidence accumulation, culminating at time of peak discrimination. Moreover, trial-by-trial fluctuations in the accumulation rate of nominally identical stimuli were predictive of participants' likelihood to opt-out of the task, suggesting that confidence emerges from the decision process itself and is computed continuously as the process unfolds. Correspondingly, source reconstruction placed these signals in regions previously implicated in decision making, within the prefrontal and parietal cortices. Crucially, control analyses ensured that these results could not be explained by stimulus difficulty, lapses in attention or decision accuracy.
•Choice confidence emerges as early as the decision process itself.•Choice confidence is reflected in the accumulation rate of decision evidence.•Source generators for choice confidence in lateral prefrontal and parietal cortices.•Metacognitive appraisal could depend on early signatures of confidence.
Journal Article
Distributing Learning Over Time: The Spacing Effect in Children's Acquisition and Generalization of Science Concepts
The spacing effect describes the robust finding that long-term learning is promoted when learning events are spaced out in time rather than presented in immediate succession. Studies of the spacing effect have focused on memory processes rather than for other types of learning, such as the acquisition and generalization of new concepts. In this study, early elementary school children (5- to 7-year-olds; N = 36) were presented with science lessons on 1 of 3 schedules: massed, clumped, and spaced. The results revealed that spacing lessons out in time resulted in higher generalization performance for both simple and complex concepts. Spaced learning schedules promote several types of learning, strengthening the implications of the spacing effect for educational practices and curriculum.
Journal Article
Attention during natural vision warps semantic representation across the human brain
The authors use functional magnetic resonance imaging to measure how the semantic representation changes when searching for different object categories in natural movies. They find tuning shifts that expand the representation of the attended category and of semantically related, but unattended, categories, and compress the representation of categories semantically dissimilar to the target.
Little is known about how attention changes the cortical representation of sensory information in humans. On the basis of neurophysiological evidence, we hypothesized that attention causes tuning changes to expand the representation of attended stimuli at the cost of unattended stimuli. To investigate this issue, we used functional magnetic resonance imaging to measure how semantic representation changed during visual search for different object categories in natural movies. We found that many voxels across occipito-temporal and fronto-parietal cortex shifted their tuning toward the attended category. These tuning shifts expanded the representation of the attended category and of semantically related, but unattended, categories, and compressed the representation of categories that were semantically dissimilar to the target. Attentional warping of semantic representation occurred even when the attended category was not present in the movie; thus, the effect was not a target-detection artifact. These results suggest that attention dynamically alters visual representation to optimize processing of behaviorally relevant objects during natural vision.
Journal Article
Combating Health Care Fraud and Abuse: Conceptualization and Prototyping Study of a Blockchain Antifraud Framework
An estimated US $2.6 billion loss is attributed to health care fraud and abuse. With traditional health care claims verification and reimbursement, the health care provider submits a claim after rendering services to a patient, which is then verified and reimbursed by the payer. However, this process leaves out a critical stakeholder: the patient for whom the services are actually rendered. This lack of patient participation introduces a risk of fraud and abuse. Blockchain technology enables secure data management with transparency, which could mitigate this risk of health care fraud and abuse.
The aim of this study is to develop a framework using blockchain to record claims data and transactions in an immutable format and to enable the patient to act as a validating node to help detect and prevent health care fraud and abuse.
We developed a health care fraud and abuse blockchain technical framework and prototype using key blockchain tools and application layers including consensus algorithms, smart contracts, tokens, and governance based on digital identity on the Ethereum platform (Ethereum Foundation).
Our technical framework maps to the claims adjudication process and focuses on Medicare claims, with the US Centers for Medicare and Medicaid Services (CMS) as the central authority. A prototype of the framework system was developed using the blockchain platform Ethereum (Ethereum Foundation), with its design features, workflow, smart contract functions, system architecture, and software implementation outlined. The software stack used to build the system consisted of a front-end user interface framework, a back-end processing server, and a blockchain network. React was used for the user interface framework, and NodeJS and an Express server were used for the back-end processing server; Solidity was the smart contract language used to interact with a local Ethereum blockchain network.
The proposed framework and the initial prototype have the potential to improve the health care claims process by using blockchain technology for secure data storage and consensus mechanisms, which make the claims adjudication process more patient-centric for the purposes of identifying and preventing health care fraud and abuse. Future work will focus on the use of synthetic or historic CMS claims data to assess the real-world viability of the framework.
Journal Article
Scaling of Advanced Theory-of-Mind Tasks
Advanced theory-of-mind (AToM) development was investigated in three separate studies involving 82, 466, and 402 elementary school children (8-, 9-, and 10-year-olds). Rasch and factor analyses assessed whether common conceptual development underlies higher-order false-belief understanding, social understanding, emotion recognition, and perspective-taking abilities. The results refuted a unidimensional scale and revealed three distinct AToM factors: social reasoning, reasoning about ambiguity, and recognizing transgressions of social norms. Developmental progressions emerged for the two reasoning factors but not for recognizing transgressions of social norms. Both social factors were significantly related to inhibition, whereas language development only predicted performance on social reasoning. These findings suggest that AToM comprises multiple abilities, which are subject to distinct cognitive influences. Importantly, only two AToM factors involve conceptual development.
Journal Article
New fundamental evidence of non-classical structure in the combination of natural concepts
We recently performed cognitive experiments on conjunctions and negations of two concepts with the aim of investigating the combination problem of concepts. Our experiments confirmed the deviations (conceptual vagueness, underextension, overextension etc.) from the rules of classical (fuzzy) logic and probability theory observed by several scholars in concept theory, while our data were successfully modelled in a quantum-theoretic framework developed by ourselves. In this paper, we isolate a new, very stable and systematic pattern of violation of classicality that occurs in concept combinations. In addition, the strength and regularity of this non-classical effect leads us to believe that it occurs at a more fundamental level than the deviations observed up to now. It is our opinion that we have identified a deep non-classical mechanism determining not only how concepts are combined but, rather, how they are formed. We show that this effect can be faithfully modelled in a two-sector Fock space structure, and that it can be exactly explained by assuming that human thought is the superposition of two processes, a 'logical reasoning', guided by 'logic', and a 'conceptual reasoning', guided by 'emergence', and that the latter generally prevails over the former. All these findings provide new fundamental support to our quantum-theoretic approach to human cognition.
Journal Article
Same/Different Abstract Concept Learning by Archerfish (Toxotes chatareus)
While several phylogenetically diverse species have proved capable of learning abstract concepts, previous attempts to teach fish have been unsuccessful. In this report, the ability of archerfish (Toxotes chatareus) to learn the concepts of sameness and difference using a simultaneous two-item discrimination task was tested. Six archerfish were trained to either select a pair of same or different stimuli which were presented simultaneously. Training consisted of a 2-phase approach. Training phase 1: the symbols in the same and different pair did not change, thereby allowing the fish to solve the test through direct association. The fish were trained consecutively with four different sets of stimuli to familiarize them with the general procedure before moving on to the next training phase. Training phase 2: six different symbols were used to form the same or different pairs. After acquisition, same/different concept learning was tested by presenting fish with six novel stimuli (transfer test). Five fish successfully completed the first training phase. Only one individual passed the second training phase, however, transfer performance was consistent with chance. This individual was given further training using 60 training exemplars but the individual was unable to reach the training criterion. We hypothesize that archerfish are able to solve a limited version of the same/different test by learning the response to each possible stimulus configuration or by developing a series of relatively simple choice contingencies. We conclude that the simultaneous two-item discrimination task we describe cannot be successfully used to test the concepts of same and different in archerfish. In addition, despite considerable effort training archerfish using several tests and training methods, there is still no evidence that fish can learn an abstract concept-based test.
Journal Article