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Todd Wareham - One of the best experts on this subject based on the ideXlab platform.
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cognition and Intractability a guide to classical and parameterized complexity analysis
2019Co-Authors: Iris Van Rooij, Johan Kwisthout, Mark Blokpoel, Todd WarehamAbstract:Intractability is a growing concern across the cognitive sciences: while many models of cognition can describe and predict human behavior in the lab, it remains unclear how these models can scale to situations of real-world complexity. Cognition and Intractability is the first book to provide an accessible introduction to computational complexity analysis and its application to questions of Intractability in cognitive science. Covering both classical and parameterized complexity analysis, it introduces the mathematical concepts and proof techniques that can be used to test one's intuition of (in)tractability. It also describes how these tools can be applied to cognitive modeling to deal with Intractability, and its ramifications, in a systematic way. Aimed at students and researchers in philosophy, cognitive neuroscience, psychology, artificial intelligence, and linguistics who want to build a firm understanding of Intractability and its implications in their modeling work, it is an ideal resource for teaching or self-study.
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Rational analysis, Intractability, and the prospects of ‘as if’-explanations
Synthese, 2018Co-Authors: Iris Rooij, Cory D. Wright, Johan Kwisthout, Todd WarehamAbstract:The plausibility of so-called ‘rational explanations’ in cognitive science is often contested on the grounds of computational Intractability. Some have argued that Intractability is a pseudoproblem, however, because cognizers do not actually perform the rational calculations posited by rational models; rather, they only behave as if they do. Whether or not the problem of Intractability is dissolved by this gambit critically depends, inter alia, on the semantics of the ‘as if’ connective. First, this paper examines the five most sensible explications in the literature, and concludes that none of them actually circumvents the problem. Hence, rational ‘as if’ explanations must obey the minimal computational constraint of tractability. Second, this paper describes how rational explanations could satisfy the tractability constraint. Our approach suggests a computationally unproblematic interpretation of ‘as if’ that is compatible with the original conception of rational analysis.
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Rational analysis, Intractability, and the prospects of 'as if'-explanations
Synthese, 2014Co-Authors: Iris Rooij, Johan Kwisthout, Crispin Wright, Todd WarehamAbstract:The plausibility of so-called ‘rational explanations’ in cognitive science is often contested on the grounds of computational Intractability. Some have argued that Intractability is a pseudoproblem, however, because cognizers do not actually perform the rational calculations posited by rational models; rather, they only behave as if they do. Whether or not the problem of Intractability is dissolved by this gambit critically depends, inter alia, on the semantics of the ‘as if’ connective. First, this paper examines the five most sensible explications in the literature, and concludes that none of them actually circumvents the problem. Hence, rational ‘as if’ explanations must obey the minimal computational constraint of tractability. Second, this paper describes how rational explanations could satisfy the tractability constraint. Our approach suggests a computationally unproblematic interpretation of ‘as if’ that is compatible with the original conception of rational analysis.
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Intractability and approximation of optimization theories of cognition
Journal of Mathematical Psychology, 2012Co-Authors: Iris Van Rooij, Todd WarehamAbstract:Many computational- or rational-level theories of human cognition suffer from computational Intractability: the postulated optimization functions are impossible to compute in a reasonable time by a finite mind/brain, or any other computational mechanism. It has been proposed that such intractable theories can nevertheless have explanatory force if we assume that human cognitive processes somehow approximate the optimal function. This raises the question of when a cognitive process can be said to approximate an optimal function. In this paper, we distinguish between two notions of approximation, called value-approximation and structure-approximation respectively, and show that they are not equivalent. Although a mathematical framework for assessing degrees of tractable value-approximability has long been available, no such framework previously existed for structure-approximability. In this paper, we present a framework consisting of definitions and proof techniques for assessing degrees of structure-approximability. We illustrate the use of our framework for a particular intractable cognitive theory, i.e., Thagard and Verbeurgt’s (1998) Coherence model, known to be equivalent to harmony maximization in Hopfield networks. We discuss implications of our findings for this class of theories, as well as explain how similar results may be derived for other intractable optimization theories of cognition.
Katherine C. Nickels - One of the best experts on this subject based on the ideXlab platform.
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what predicts enduring Intractability in children who appear medically intractable in the first 2 years after diagnosis
Epilepsia, 2013Co-Authors: Elaine C. Wirrell, Jay Mandrekar, Lily C Wongkisiel, Katherine C. NickelsAbstract:Summary Purpose In a population-based retrospective cohort of children with newly diagnosed epilepsy, to determine (1) what proportion meet criteria for early medical Intractability, and (2) predictors of enduring Intractability. Methods Children with newly diagnosed epilepsy between 1980 and 2009 while resident in Olmsted County, MN, and followed >36 months, were stratified into groups based on both early medical Intractability (“apparent” medical Intractability in the first 2 years) and enduring Intractability (persisting Intractability at final follow-up or having undergone surgery for intractable epilepsy), and variables predicting these outcomes were evaluated. Key Findings Three hundred eighty-one children were included, representing 81% of our cohort with newly diagnosed epilepsy. Seventy five (19.7%) had early medical Intractability, and predictors of this outcome on multivariable analysis were neuroimaging abnormality (risk ratio, 2.70; p = 0.0004), abnormal neurologic examination at diagnosis (risk ratio, 1.87; p = 0.015), and mode of onset (association was significant for focal vs. generalized onset [risk ratio, 0.25; p < 0.0001] but not unknown vs. generalized onset [p = 0.065]). After a median follow-up of 11.7 years, 49% remained intractable, 8% had rare seizures (≤ every 6 months), and the remainder were seizure-free. The only factor predicting enduring Intractability on multivariable analysis was neuroimaging abnormality (risk ratio, 7.0; p = 0.0006). Significance Although a significant minority of children with early medical Intractability ultimately achieved seizure control without surgery, those with an abnormal imaging study did poorly. For this subgroup, early surgical intervention is strongly advised to limit comorbidities of ongoing, intractable seizures. Conversely, a cautious approach is suggested for those with normal imaging, as most will remit with time.
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What predicts enduring Intractability in children who appear medically intractable in the first 2 years after diagnosis
Epilepsia, 2013Co-Authors: Elaine C. Wirrell, Lily C. Wong-kisiel, Jay Mandrekar, Katherine C. NickelsAbstract:Summary Purpose In a population-based retrospective cohort of children with newly diagnosed epilepsy, to determine (1) what proportion meet criteria for early medical Intractability, and (2) predictors of enduring Intractability. Methods Children with newly diagnosed epilepsy between 1980 and 2009 while resident in Olmsted County, MN, and followed >36 months, were stratified into groups based on both early medical Intractability (“apparent” medical Intractability in the first 2 years) and enduring Intractability (persisting Intractability at final follow-up or having undergone surgery for intractable epilepsy), and variables predicting these outcomes were evaluated. Key Findings Three hundred eighty-one children were included, representing 81% of our cohort with newly diagnosed epilepsy. Seventy five (19.7%) had early medical Intractability, and predictors of this outcome on multivariable analysis were neuroimaging abnormality (risk ratio, 2.70; p = 0.0004), abnormal neurologic examination at diagnosis (risk ratio, 1.87; p = 0.015), and mode of onset (association was significant for focal vs. generalized onset [risk ratio, 0.25; p
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predictors and course of medically intractable epilepsy in young children presenting before 36 months of age a retrospective population based study
Epilepsia, 2012Co-Authors: Elaine C. Wirrell, Jay Mandrekar, Lily C Wongkisiel, Katherine C. NickelsAbstract:Summary Purpose: To determine the prevalence and identify predictors of medical Intractability in children presenting with epilepsy before 36 months of age, and to assess the effect of medical Intractability on long-term mortality and intellectual function. Methods: Children with newly diagnosed epilepsy before 36 months between 1980 and 2009 while resident in Olmsted County, MN, were identified. Medical records were reviewed to collect epilepsy-specific variables and long-term outcome data. Medically intractable epilepsy was defined as either (1) seizure frequency greater than every 6 months at final follow-up and failure of two or more antiepileptic drugs for lack of efficacy, or (2) having undergone epilepsy surgery after failure to respond to two or more antiepileptic drugs. Key Findings: One hundred twenty-seven children with new-onset epilepsy were identified and followed for a median of 78 months. Medically intractable seizures occurred in 35%, and significant predictors on multivariate analysis were age ≤12 months at diagnosis (odds ratio [OR] 6.76, 95% confidence interval [CI] 2.00, 22.84, p = 0.002), developmental delay at initial diagnosis of epilepsy (OR 20.03, 95% CI 3.49, 114.83, p = 0.0008), neuroimaging abnormality (OR 6.48, 95% CI 1.96, 21.40, p = 0.002), and focal slowing on initial EEG (OR 5.33, 95% CI 1.14, 24.88, p = 0.03). Medical Intractability occurred early in the course in most children, being seen in 61% by 1 year, and 93% by 5 years after initial diagnosis. Mortality was higher (20% vs. 0%, p < 0.001) and intellectual outcome poorer (p < 0.001) if epilepsy was medically intractable. Significance: One third of children presenting with epilepsy before 36 months will be medically intractable, and significant predictors are identified. Medically intractable epilepsy is associated with increased mortality risk and significant intellectual disability.
Yoshinori Iwatani - One of the best experts on this subject based on the ideXlab platform.
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gene polymorphisms of vegf and vegfr2 are associated with the severity of hashimoto s disease and the Intractability of graves disease respectively
Endocrine Journal, 2020Co-Authors: Mami Okamoto, Mikio Watanabe, Naoya Inoue, Kazane Ogawa, Yoh Hidaka, Yoshinori IwataniAbstract:Vascular endothelial growth factor (VEGF) is one of main regulators of angiogenesis that functions by binding to its receptors, including VEGF receptor (VEGFR) 2. There are few data available regarding the association between VEGF and VEGFR polymorphisms and the susceptibility to and prognosis of autoimmune thyroid diseases (AITDs). To elucidate this association, we genotyped four functional VEGF and two VEGFR2 polymorphisms and measured serum VEGF levels. In the four functional VEGF polymorphisms, the frequencies of the I carrier and I allele of VEGF -2549 I/D, which has lower activity, were higher in patients with severe HD than in those with mild HD. In the two functional VEGFR2 polymorphisms, the frequency of the rs2071559 CC genotype, which has higher activity, was higher in patients with intractable GD than in controls, and the proportion of GD patients with larger goiters was higher in those with the CC genotype. Moreover, the frequency of the rs1870377 TT genotype with higher activity was higher in patients with intractable GD than in those with GD in remission. Combinations of VEGF and VEGFR2 polymorphisms with stronger interactions were associated with the Intractability of GD. Serum VEGF levels were higher in HD and AITD patients than those in controls. In conclusion, VEGF polymorphisms with lower activity were associated with the severity of HD, while VEGFR2 polymorphisms and the combinations of VEGF and VEGFR2 polymorphisms, which have stronger interactions, were associated with the Intractability of GD. VEGF and VEGFR2 polymorphisms were associated with HD severity and GD Intractability, respectively.
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the 590cc genotype in the il4 gene as a strong predictive factor for the development of hypothyroidism in hashimoto disease
Clinical Chemistry, 2008Co-Authors: Takashi Nanba, Mikio Watanabe, Takashi Akamizu, Yoshinori IwataniAbstract:The severity of Hashimoto disease (HD) varies among patients and is difficult to predict when the disease is in the subclinical state and diagnosed by the presence of thyroid-specific autoantibody. Likewise, the Intractability of Graves disease (GD) is difficult to predict. Autoimmune thyroid destruction that underlies both diseases is strongly determined by T-cell cytotoxicity, which is activated by interferon (IFN)-γ (1), and the T allele in +874A/T polymorphism of the interferon gamma ( IFNG ) gene, which promotes increased IFN-γ production, has been noted more frequently among patients with severe HD (2). Cytokine balance between T-helper 1 (Th1) cytokines, such as IFN-γ, and Th2 cytokines is important in immune regulation (3). Therefore, it is possible that Th2 cytokines may also affect the severity of HD and the Intractability of GD. Interleukin (IL)-4, one …
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the 869t c polymorphism in the transforming growth factor β1 gene is associated with the severity and Intractability of autoimmune thyroid disease
Clinical and Experimental Immunology, 2008Co-Authors: Hiroya Yamada, Takashi Nanba, Mikio Watanabe, Takashi Akamizu, Yoshinori IwataniAbstract:The severity of Hashimoto's disease (HD) and the Intractability of Graves' disease (GD) vary among patients. To clarify whether the +869T/C polymorphism in the transforming growth factor-beta1 (TGF-beta1) gene, which is associated with TGF-beta1 expression, is involved in the Intractability of GD and severity of HD, we genotyped the TGF-beta1 +869T/C polymorphism by polymerase chain reaction-restriction fragment length polymorphism method in genomic DNA samples from 33 patients with HD who developed hypothyroidism before they were 50 years old (severe HD) and 30 untreated, euthyroid patients with HD who were older than 50 years (mild HD). We also examined 48 euthyroid patients with GD who had been under treatment and were still positive for anti-thyrotropin receptor antibodies (intractable GD), 20 euthyroid patients with GD in remission and 45 healthy controls. The frequency of the T allele and the TT genotype were higher in patients with severe HD than in those with in mild HD. In contrast, the frequency of the CC genotype was higher in patients with intractable GD than in patients with GD in remission. In conclusion, the +869T/C polymorphism in the TGF-beta1 gene is associated with the severity and Intractability of autoimmune thyroid disease.
Justin O. Parkhurst - One of the best experts on this subject based on the ideXlab platform.
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Appeals to evidence for the resolution of wicked problems: the origins and mechanisms of evidentiary bias
Policy Sciences, 2016Co-Authors: Justin O. ParkhurstAbstract:Wicked policy problems are often said to be characterized by their ‘Intractability’, whereby appeals to evidence are unable to provide policy resolution. Advocates for ‘Evidence Based Policy’ (EBP) often lament these situations as representing the misuse of evidence for strategic ends, while critical policy studies authors counter that policy decisions are fundamentally about competing values, with the (blind) embrace of technical evidence depoliticizing political decisions. This paper aims to help resolve these conflicts and, in doing so, consider how to address this particular feature of problem wickedness. Specifically the paper delineates two forms of evidentiary bias that drive Intractability, each of which is reflected by contrasting positions in the EBP debates: ‘technical bias’—referring to invalid uses of evidence; and ‘issue bias’—referring to how pieces of evidence direct policy agendas to particular concerns. Drawing on the fields of policy studies and cognitive psychology, the paper explores the ways in which competing interests and values manifest in these forms of bias, and shape evidence utilization through different mechanisms. The paper presents a conceptual framework reflecting on how the nature of policy problems in terms of their complexity , contestation , and polarization can help identify the potential origins and mechanisms of evidentiary bias leading to Intractability in some wicked policy debates. The discussion reflects on how a better understanding about such mechanisms could inform future work to mitigate or overcome such Intractability.
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Appeals to evidence for the resolution of wicked problems: the origins and mechanisms of evidentiary bias
Policy Sciences, 2016Co-Authors: Justin O. ParkhurstAbstract:Wicked policy problems are often said to be characterized by their ‘Intractability’, whereby appeals to evidence are unable to provide policy resolution. Advocates for ‘Evidence Based Policy’ (EBP) often lament these situations as representing the misuse of evidence for strategic ends, while critical policy studies authors counter that policy decisions are fundamentally about competing values, with the (blind) embrace of technical evidence depoliticizing political decisions. This paper aims to help resolve these conflicts and, in doing so, consider how to address this particular feature of problem wickedness. Specifically the paper delineates two forms of evidentiary bias that drive Intractability, each of which is reflected by contrasting positions in the EBP debates: ‘technical bias’—referring to invalid uses of evidence; and ‘issue bias’—referring to how pieces of evidence direct policy agendas to particular concerns. Drawing on the fields of policy studies and cognitive psychology, the paper explores the ways in which competing interests and values manifest in these forms of bias, and shape evidence utilization through different mechanisms. The paper presents a conceptual framework reflecting on how the nature of policy problems in terms of their complexity , contestation , and polarization can help identify the potential origins and mechanisms of evidentiary bias leading to Intractability in some wicked policy debates. The discussion reflects on how a better understanding about such mechanisms could inform future work to mitigate or overcome such Intractability.
Elaine C. Wirrell - One of the best experts on this subject based on the ideXlab platform.
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what predicts enduring Intractability in children who appear medically intractable in the first 2 years after diagnosis
Epilepsia, 2013Co-Authors: Elaine C. Wirrell, Jay Mandrekar, Lily C Wongkisiel, Katherine C. NickelsAbstract:Summary Purpose In a population-based retrospective cohort of children with newly diagnosed epilepsy, to determine (1) what proportion meet criteria for early medical Intractability, and (2) predictors of enduring Intractability. Methods Children with newly diagnosed epilepsy between 1980 and 2009 while resident in Olmsted County, MN, and followed >36 months, were stratified into groups based on both early medical Intractability (“apparent” medical Intractability in the first 2 years) and enduring Intractability (persisting Intractability at final follow-up or having undergone surgery for intractable epilepsy), and variables predicting these outcomes were evaluated. Key Findings Three hundred eighty-one children were included, representing 81% of our cohort with newly diagnosed epilepsy. Seventy five (19.7%) had early medical Intractability, and predictors of this outcome on multivariable analysis were neuroimaging abnormality (risk ratio, 2.70; p = 0.0004), abnormal neurologic examination at diagnosis (risk ratio, 1.87; p = 0.015), and mode of onset (association was significant for focal vs. generalized onset [risk ratio, 0.25; p < 0.0001] but not unknown vs. generalized onset [p = 0.065]). After a median follow-up of 11.7 years, 49% remained intractable, 8% had rare seizures (≤ every 6 months), and the remainder were seizure-free. The only factor predicting enduring Intractability on multivariable analysis was neuroimaging abnormality (risk ratio, 7.0; p = 0.0006). Significance Although a significant minority of children with early medical Intractability ultimately achieved seizure control without surgery, those with an abnormal imaging study did poorly. For this subgroup, early surgical intervention is strongly advised to limit comorbidities of ongoing, intractable seizures. Conversely, a cautious approach is suggested for those with normal imaging, as most will remit with time.
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What predicts enduring Intractability in children who appear medically intractable in the first 2 years after diagnosis
Epilepsia, 2013Co-Authors: Elaine C. Wirrell, Lily C. Wong-kisiel, Jay Mandrekar, Katherine C. NickelsAbstract:Summary Purpose In a population-based retrospective cohort of children with newly diagnosed epilepsy, to determine (1) what proportion meet criteria for early medical Intractability, and (2) predictors of enduring Intractability. Methods Children with newly diagnosed epilepsy between 1980 and 2009 while resident in Olmsted County, MN, and followed >36 months, were stratified into groups based on both early medical Intractability (“apparent” medical Intractability in the first 2 years) and enduring Intractability (persisting Intractability at final follow-up or having undergone surgery for intractable epilepsy), and variables predicting these outcomes were evaluated. Key Findings Three hundred eighty-one children were included, representing 81% of our cohort with newly diagnosed epilepsy. Seventy five (19.7%) had early medical Intractability, and predictors of this outcome on multivariable analysis were neuroimaging abnormality (risk ratio, 2.70; p = 0.0004), abnormal neurologic examination at diagnosis (risk ratio, 1.87; p = 0.015), and mode of onset (association was significant for focal vs. generalized onset [risk ratio, 0.25; p
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predictors and course of medically intractable epilepsy in young children presenting before 36 months of age a retrospective population based study
Epilepsia, 2012Co-Authors: Elaine C. Wirrell, Jay Mandrekar, Lily C Wongkisiel, Katherine C. NickelsAbstract:Summary Purpose: To determine the prevalence and identify predictors of medical Intractability in children presenting with epilepsy before 36 months of age, and to assess the effect of medical Intractability on long-term mortality and intellectual function. Methods: Children with newly diagnosed epilepsy before 36 months between 1980 and 2009 while resident in Olmsted County, MN, were identified. Medical records were reviewed to collect epilepsy-specific variables and long-term outcome data. Medically intractable epilepsy was defined as either (1) seizure frequency greater than every 6 months at final follow-up and failure of two or more antiepileptic drugs for lack of efficacy, or (2) having undergone epilepsy surgery after failure to respond to two or more antiepileptic drugs. Key Findings: One hundred twenty-seven children with new-onset epilepsy were identified and followed for a median of 78 months. Medically intractable seizures occurred in 35%, and significant predictors on multivariate analysis were age ≤12 months at diagnosis (odds ratio [OR] 6.76, 95% confidence interval [CI] 2.00, 22.84, p = 0.002), developmental delay at initial diagnosis of epilepsy (OR 20.03, 95% CI 3.49, 114.83, p = 0.0008), neuroimaging abnormality (OR 6.48, 95% CI 1.96, 21.40, p = 0.002), and focal slowing on initial EEG (OR 5.33, 95% CI 1.14, 24.88, p = 0.03). Medical Intractability occurred early in the course in most children, being seen in 61% by 1 year, and 93% by 5 years after initial diagnosis. Mortality was higher (20% vs. 0%, p < 0.001) and intellectual outcome poorer (p < 0.001) if epilepsy was medically intractable. Significance: One third of children presenting with epilepsy before 36 months will be medically intractable, and significant predictors are identified. Medically intractable epilepsy is associated with increased mortality risk and significant intellectual disability.
