Immediate and delayed recognition of visual stimuli in poor and normal readers.

The present study investigated the hypothesis that specific reading disability is attributable to inadequate visual memory. Previous research had demonstrated that poor readers sustain no basic dysfunction in visual perception, but there was need to evaluate the possibility that deficiencies in letter and word recognition result from disorder in long-term visual storage. Adopting a format employed in a previous study, randomly arranged Hebrew letters were presented to poor and normal readers unfamiliar with Hebrew, and both groups were asked to demonstrate retention for these stimuli on three separate occasions: immediately after initial presentation, 24 hours later and 6 months later. As a control measure, the performance of the non-Hebrew subjects was compared with that of normal readers familiar with Hebrew letters. It was found that retention in the non-Hebrew groups was equivalent under all of the temporal conditions, but the performance of both was poorer than the Hebrew groups under the immediate and 24-hour conditions. However, none of the reader groups differed in the case of retention after a 6-month delay period. It was concluded that deficient visual memory is an unlikely source of specific reading disability, and alternative explanations of the disorder were considered.     

Patterns of regional cerebral blood flow during attempted reading aloud by stutterers both on and off haloperidol medication: Evidence for inadequate left frontal activation during stuttering

Two stutterers, both recent college graduates, were subjected to regional cerebral blood flow measurements while attempting to read aloud. Each one received two measurements, one of which was under the influence of haloperidol, 3 mg daily. Both subjects showed improvement on medication, allowing a stuttering versus essentially no stuttering comparisons for each subject. Both subjects showed higher Broca's area flow in the right compared to the left hemisphere, during stuttering. Both showed higher Wernicke's area flow in the left compared to the right hemisphere, however, during stuttering. During reading aloud without stuttering, however, the Brocas's area flows were reversed, now showing a left hemisphere advantage. The results were interpreted as consistent with H. M. Sussman and P. F. MacNeilage's (1975, Neuropsychologia, 13, 19–26) proposal that stutterers exhibit conventional left cerebral dominance for speech reception, but inadequate left cerebral dominance for speech production.     

On going (and getting) nowhere with our words: New skepticism about the philosophical method of cases

The philosophical “method of cases” has been the subject of intense discussion. In a recent paper, Frank Jackson attempts to vindicate the method by proposing that it is underwritten by the “representational view of language.” Jackson's proposal is potentially very significant. For if it is true, then the method of cases stands, but quite possibly also falls, with the representational view of language as characterized by Jackson. The aim of this paper is to question the philosophical method of cases by showing that it does in fact presuppose a particular view of language that is at the very least questionable, both philosophically and empirically.     

Analytic model for the line tension of a bowing dislocation segment

The resistance of a dislocation to bowing under stress governs the strength of the gamut of metallic material systems. This resistance is commonly referred to as the dislocation line tension (Γ) and is employed ubiquitously within continuum scale models of metal plasticity. Despite its significance, a unifying model for the line tension of a bowing dislocation segment, which has been analytically derived and independently reproduces simulation results, remains lacking. Here, we report a model for Γ of a curved, semicircular bowing dislocation segment. Upon applying our model to the operative stress of a Frank–Read dislocation source, we predict a prelogarithmic scaling of the Frank–Read source strength in agreement with existing simulation results. Moreover, in the limit of infinitesimal bowout we predict a prelogarithmic line tension factor which also agrees with theoretical analyses. Our model provides insight into the evolution of an arbitrarily oriented, stressed dislocation segment without resorting to numerical methods.     

“Where Is Everybody?” Fermi’s Paradox,Evolution, and Sin

The Search for Extraterrestrial Intelligence (SETI) project has been scanning the heavens for signs of intelligent life for almost half a century. So far, nothing. This raises the question physicist Enrico Fermi asked, “Where is everybody?” The probability of intelligent life on another planet is high so why the silence? Technological civilizations may be short-lived. The mechanisms of evolution that lead to intelligent life and technological development also lead to propensities traditionally labeled as sin. These propensities make it difficult for technological civilizations to survive long enough to escape their home planet.