Alternate forms of prose passages for the assessment of auditory-verbal memory.
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Logical memory (LM) is the most frequently administered subtest from the Wechsler Memory Scale; however, the lack of alternate equivalent forms for this subtest may limit its clinical utility. Six new paragraphs modelled on LM stories were developed. Stories were matched on attributes such as number of words and readability. Passage attributes for the six stories were compared with those of standard LM stories (WMS-R and WMS-III versions) to examine story equivalence. The psychometric properties of new passages were also calculated to assess task difficulty and interrater reliability. Results from these analyses suggest a high degree of overlap between the attributes of the new stories and some interesting discrepancies between passage attributes of WMS-R and WMS-III LM stories. In addition, interrater reliability of new passages was found to be excellent (at least .97), and when combined into three sets of passage-pairs, these pairs were found have equivalent difficulty. To reduce the potential for practice effects by use of alternate forms, these new logical memory-style passages may facilitate repeat assessment of auditory-verbal memory. (+info)
The meaning and computation of causal power: comment on Cheng (1997) and Novick and Cheng (2004).
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D. Hume (1739/1987) argued that causality is not observable. P. W. Cheng (1997) claimed to present "a theoretical solution to the problem of causal induction first posed by Hume more than two and a half centuries ago" (p. 398) in the form of the power PC theory (L. R. Novick & P. W. Cheng, 2004). This theory claims that people's goal in causal induction is to estimate causal powers from observable covariation and outlines how this can be done in specific conditions. The authors first demonstrate that if the necessary assumptions were ever met, causal powers would be self-evident to a reasoner--they are either 0 or 1--making the theory unnecessary. The authors further argue that the assumptions the power PC theory requires to compute causal power are unobtainable in the real world and, furthermore, people are aware that requisite assumptions are violated. Therefore, the authors argue that people do not attempt to compute causal power. (+info)
On the classic and modern theories of matching.
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Classic matching theory, which is based on Herrnstein's (1961) original matching equation and includes the well-known quantitative law of effect, is almost certainly false. The theory is logically inconsistent with known experimental findings, and experiments have shown that its central constant-k assumption is not tenable. Modern matching theory, which is based on the power function version of the original matching equation, remains tenable, although it has not been discussed or studied extensively. The modern theory is logically consistent with known experimental findings, it predicts the fact and details of the violation of the classic theory's constant-k assumption, and it accurately describes at least some data that are inconsistent with the classic theory. (+info)
A proposal to classify happiness as a psychiatric disorder.
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It is proposed that happiness be classified as a psychiatric disorder and be included in future editions of the major diagnostic manuals under the new name: major affective disorder, pleasant type. In a review of the relevant literature it is shown that happiness is statistically abnormal, consists of a discrete cluster of symptoms, is associated with a range of cognitive abnormalities, and probably reflects the abnormal functioning of the central nervous system. One possible objection to this proposal remains--that happiness is not negatively valued. However, this objection is dismissed as scientifically irrelevant. (+info)
Can arguments address concerns?
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People have concerns, and ethicists often respond to them with philosophical arguments. But can conceptual constructions properly address fears and anxieties? It is argued in this paper that while it is possible to voice, clarify, create and-to a certain extent-tackle concerns by arguments, more concrete practices, choices, and actions are normally needed to produce proper responses to people's worries. While logical inconsistencies and empirical errors can legitimately be exposed by arguments, the situation is considerably less clear when it comes to moral, cultural, and emotional norms, values, and expectations. (+info)
A landmark for popperian epidemiology: refutation of the randomised Aldactone evaluation study.
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In 1999 a great multi-site clinical trial known as the randomised Aldactone evaluation study (RALES) showed that the use of spironolactone importantly reduced complications attributable to chronic heart failure without major negative side effects. Recently, RALES has been questioned by a large scale observational study in the Ontario population. In contrast with predictions, the complications and mortality increased dramatically because of hyperkalaemia, reaching dimensions that from a public health perspective are comparable to an epidemic. This review analyses both researches in the light of Karl Popper's science theory applying the modus tollens syllogism to the reality proposed by the main empirical enunciations that ensue from its epidemiological designs. RALES is deductively refuted because of the non-fulfillment of auxiliary assumptions that would act as reciprocal potential falsifiers in both studies, taking the logical form of a bi-conditional argument of the type: (a) P-then-Q and (b) Q-if-X(P), X(P) being a set of potential falsifiers of Q as part of the explicit falsity content of P. From this popperian model, implications for clinical research are discussed. (+info)
Signal propagation and logic gating in networks of integrate-and-fire neurons.
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Transmission of signals within the brain is essential for cognitive function, but it is not clear how neural circuits support reliable and accurate signal propagation over a sufficiently large dynamic range. Two modes of propagation have been studied: synfire chains, in which synchronous activity travels through feedforward layers of a neuronal network, and the propagation of fluctuations in firing rate across these layers. In both cases, a sufficient amount of noise, which was added to previous models from an external source, had to be included to support stable propagation. Sparse, randomly connected networks of spiking model neurons can generate chaotic patterns of activity. We investigate whether this activity, which is a more realistic noise source, is sufficient to allow for signal transmission. We find that, for rate-coded signals but not for synfire chains, such networks support robust and accurate signal reproduction through up to six layers if appropriate adjustments are made in synaptic strengths. We investigate the factors affecting transmission and show that multiple signals can propagate simultaneously along different pathways. Using this feature, we show how different types of logic gates can arise within the architecture of the random network through the strengthening of specific synapses. (+info)
Explanation and understanding.
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The study of explanation, while related to intuitive theories, concepts, and mental models, offers important new perspectives on high-level thought. Explanations sort themselves into several distinct types corresponding to patterns of causation, content domains, and explanatory stances, all of which have cognitive consequences. Although explanations are necessarily incomplete--often dramatically so in laypeople--those gaps are difficult to discern. Despite such gaps and the failure to recognize them fully, people do have skeletal explanatory senses, often implicit, of the causal structure of the world. They further leverage those skeletal understandings by knowing how to access additional explanatory knowledge in other minds and by being particularly adept at using situational support to build explanations on the fly in real time. Across development and cultures, there are differences in preferred explanatory schemes, but rarely are any kinds of schemes completely unavailable to a group. (+info)