Not so fast: domain-general factors can account for selective deficits in grammatical processing

Normals display selective deficits in morphology and syntax under adverse processing conditions. Digit loads do not impair processing of passives and object relatives but do impair processing of grammatical morphemes. Perceptual degradation and temporal compression selectively impair several aspects of grammar, including passives and object relatives. Hence we replicate Caplan & Waters's specific findings but reach opposite conclusions, based on wider evidence

Grammatical morphology in aphasia: Evidence from three languages

Aspects of grammatical morphology in Broca's and Wernicke's aphasia were elicited under controlled conditions in three language groups: English, Italian and German. Results suggest that the agrammatism/paragrammatism distinction does not work well for richly-inflected languages. Language-specific ratios of closed class morphology were preserved even among non-fluent patients, with significantly more morphology produced by German and Italian patients. German and Italian patients were also much more likely to furnish the article before nouns - despite or perhaps because of the fact that articles are more complex and informative in those languages. Although patients assigned the correct article most of the time, there were a significant number of article errors (i.e. paragrammatic substitution). Error analyses showed that substitutions are not random, reflecting difficulty in access rather than loss. Substitutions were more common in German, where the complex case and gender markings on the article increase the probability of error. Within each language, error patterns were quite similar for Broca's and Wernicke's aphasics. However, at a detailed level patient group differences in error production were detected. German Broca's aphasics tend to avoid difficult case forms by substituting a simpler, less-marked morphosyntactic frame. Wernicke's aphasics try instead to.produce the more marked, oblique constructions, resulting in a less conservative error pattern

Visual Performance with High-Contrast Cathode-Ray Tubes at High Levels of Ambient Illumination

Gap-detection thresholds and working-level preferences were determined for one standard and three experimental high-contrast cathode-ray tubes under four levels of ambient illumination, 100, 1,000, 5,000, and 10,000 ft.-c.; two angles of incidence, 30 and 60°; and two angles of regard, 0 and −45° Trace brightnesses required to perform the visual tasks were primarily a function of the reflectances and resulting background brightnesses of the cathode-ray-tube faces. The results of this study are related to classical psychophysical data on brightness discrimination, earlier work on “masking luminance” for rador displays, and a recent study on visual performance using electroluminescent displays under high ambient illumination. </jats:p

Validity of Expert Judgments of Performance Time

An apparatus and a method for validating estimates of performance time and reliability against empirical measures of human performance time and reliability are described. Measures of performance time were obtained on five tasks and were correlated with estimates of performance times obtained from eight judges in a previous study. Median observed and estimated performance times were highly correlated (r = .98, p&lt;.01). Estimates of maximum performance time corresponded to the 95th to 100th percentiles of the observed distribution of performance time, but estimates of minimum performance time were high and scattered over the lower percentiles. The significant validity coefficient suggests the feasibility of using estimates of performance time, at least for some simple tasks, in system-analytic models when empirical data are lacking and are too expensive to obtain. </jats:p