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Causal Hypotheses (causal + hypothesis)
Selected AbstractsThe notion of ,phonology' in dyslexia research: cognitivism,and beyondDYSLEXIA, Issue 3 2007Per Henning Uppstad Abstract Phonology has been a central concept in the scientific study of dyslexia over the past decades. Despite its central position, however, it is a concept with no precise definition or status. The present article investigates the notion of ,phonology' in the tradition of cognitive psychology. An attempt is made to characterize the basic assumptions of the phonological approach to dyslexia and to evaluate these assumptions on the basis of commonly accepted standards of empirical science. First, the core assumptions of phonological awareness are outlined and discussed. Second, the position of Paula Tallal is presented and discussed in order to shed light on an attempt to stretch the cognitive-psychological notion of ,phonology' towards auditory and perceptual aspects. Both the core assumptions and Tallal's position are rejected as unfortunate, albeit for different reasons. Third, the outcome of this discussion is a search for what is referred to as a ,vulnerable theory' within this field. The present article claims that phonological descriptions must be based on observable linguistic behaviour, so that hypotheses can be falsified by data. Consequently, definitions of ,dyslexia' must be based on symptoms; causal aspects should not be included. In fact, we claim that causal aspects, such as ,phonological deficit', both exclude other causal hypotheses and lead to circular reasoning. If we are to use terms such as ,phonology' and ,phoneme' in dyslexia research, we must have more precise operationalizations of them. Copyright © 2007 John Wiley & Sons, Ltd. [source] Headache and Psychological Functioning in Children and AdolescentsHEADACHE, Issue 9 2006Scott W. Powers PhD Headache can affect all aspects of a child's functioning, leading to negative affective states (eg, anxiety, depression, anger) and increased psychosocial problems (for instance, school absences, problematic social interactions). For children and adolescents who experience frequent headache problems, comorbid psychological issues are a well-recognized, but poorly understood, clinical phenomenon. The confusion surrounding the relationship between pediatric headache and psychopathology exists for several reasons. First, in some cases, headache has been inappropriately attributed to psychological or personality features based on anecdotal observations or interpretations that go beyond the available data. Additionally, measures of psychopathology have not always adhered to the American Psychiatric Association's diagnostic criteria, thus reducing the reliability of diagnostic judgments. Furthermore, the diagnosis of headache has not always followed standard criteria, and has been complicated by the emergence of new terms and evolving measures. Finally, methodological shortcomings, such as incomplete descriptions of the procedures and criteria used for the study, inadequate descriptions of headache severity, lack of a control group for comparison with individuals without headaches, reliance primarily on cross-sectional research designs that are often discussed with inferences to causal hypotheses, and the use of unstandardized assessment measures, have significantly limited the validity of research findings. The goal of the current review is to examine the extant literature to provide the most up-to-date picture on what the research has made available about the magnitude, specificity, and causes of psychopathology in children and adolescents with headache, in an effort to further elucidate their relationship and prompt a more methodologically rigorous study of these issues. [source] Disproving Causal Relationships Using Observational Data,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 3 2009Henry L. Bryant Abstract Economic theory is replete with causal hypotheses that are scarcely tested because economists are generally constrained to work with observational data. We describe a method for testing a hypothesis that one observed random variable causes another. Contingent on a sufficiently strong correspondence between the two variables, an appropriately related third variable can be employed for the test. The logic of the procedure naturally suggests strong and weak grounds for rejecting the causal hypothesis. Monte Carlo results suggest that weakly grounded rejections are unreliable for small samples, but reasonably reliable for large samples. Strongly grounded rejections are highly reliable, even for small samples. [source] Decline in rheumatoid vasculitis prevalence among US veterans: A retrospective cross-sectional studyARTHRITIS & RHEUMATISM, Issue 9 2009Christie Bartels Objective To examine trends in the prevalence of rheumatoid vasculitis in a national US population comprising both hospitalized and ambulatory patients with rheumatoid arthritis (RA). Methods In this serial cross-sectional study, we analyzed data on hospitalized and ambulatory patients spanning 22 years (1985,2006) and 10 years (1997,2006), respectively, to determine the prevalence of rheumatoid vasculitis, as defined by the International Classification of Diseases, Ninth Revision. Our search encompassed data collected on a predominantly male study population during 10 million hospitalizations and outpatient visits, and included annual data on >37,000 RA patients. To test for a decrease in rheumatoid vasculitis prevalence, breakpoint analysis was performed using stepwise Chow and Durbin-Watson tests. Results There was a clear decline in the prevalence of rheumatoid vasculitis, and this decline remained evident even after accounting for a decreased number of hospitalizations among RA patients. Peak prevalence occurred among hospitalized patients in the 1980s, and prevalence gradually declined throughout the 1990s. Furthermore, simultaneous breakpoints representing a significant drop in rheumatoid vasculitis prevalence between the years 2000 and 2001 were demonstrated for both inpatients (P < 0.000) and outpatients (P < 0.003). The prevalence of vasculitis dropped 53% among inpatients and 31% among outpatients between 2000 and 2001. Conclusion Our results demonstrate a significant decline in rheumatoid vasculitis prevalence after 2000 in this nationwide sample of hospitalized and ambulatory patients. The clear, consistent drop in prevalence provides an opportunity for the formulation of causal hypotheses, including consideration of the impact of biologic agents used to treat RA, on rheumatoid vasculitis. [source] Elucidating the Relationship Between Obesity and Depression: Recommendations for Future ResearchCLINICAL PSYCHOLOGY: SCIENCE AND PRACTICE, Issue 1 2008Joshua I. Hrabosky The obese population is heterogeneous in its experiences of psychosocial disturbances, yet many obese individuals do experience such problems as body image disturbance, low self-esteem, diminished self-efficacy, and binge eating. Furthermore, recent research has repeatedly found obesity to correlate with negative affect, depressed mood, and clinical depression. In their comprehensive review, Markowitz, Friedman, and Arent (2008) identify numerous psychosocial and biological processes that they hypothesize to act as mediating factors in the relationship between obesity and depression. This commentary extends Markowitz and colleagues' review and proposed causal pathway model by (a) evaluating the specificity of the relationship between obesity and depression, and (b) providing recommendations for the empirical evaluation of causal hypotheses. [source] Disproving Causal Relationships Using Observational Data,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 3 2009Henry L. Bryant Abstract Economic theory is replete with causal hypotheses that are scarcely tested because economists are generally constrained to work with observational data. We describe a method for testing a hypothesis that one observed random variable causes another. Contingent on a sufficiently strong correspondence between the two variables, an appropriately related third variable can be employed for the test. The logic of the procedure naturally suggests strong and weak grounds for rejecting the causal hypothesis. Monte Carlo results suggest that weakly grounded rejections are unreliable for small samples, but reasonably reliable for large samples. Strongly grounded rejections are highly reliable, even for small samples. [source] Causal connections in the acquisition of an orthographic rule: a test of Uta Frith's developmental hypothesisTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 8 2006Claire Davis Background:, In a longitudinal study we tested Frith's causal hypothesis that children first gain orthographic knowledge through reading and then later, as a consequence, through spelling. Method:, Children from Years 2 and 3 were tested three times over two years on their reading and spelling of pseudo-words which conformed to the conditional orthographic rule, the ,final ,e' or ,split-digraph' rule. Results:, Cross-lagged panel correlation analyses suggested that the children's success in reading split-digraph words was a causal determinant of their learning to use split-digraphs in spelling, in the 7- to 8-year period and, with one year-group but not with the other, in the 8- to 9-year period. In the 9- to 10-year period children's success in reading no longer seemed to affect their spelling. Conclusions:, These results strongly support Frith's causal hypothesis about the development of orthographic knowledge. [source] | |||||||||||||