Processing of identity and position information in normal and disabled readers

Processing of identity and position information was investigated in normal and disabled readers at two grade levels (third/fourth grade and sixth grade). Two partial-report tasks were used. The identity task consisted of visual presentation of a five-letter array, followed by a probe letter. Subjects responded yes for a match and no for a mismatch (identity response). The identity + position task was identical except that an additional response was required on correct yes trials: subjects reported the position of the probe letter in the array (position response). Both grade level and reading ability differences were found on the identity response measure, but not on the position response measure. Results were inconsistent with the hypothesis that disabled readers have difficulties in processing order information. Reader ability differences in identity processing attenuated somewhat with age. Serial position functions for both identity and position responses suggested the presence of a left-to-right scanning operation in both age and ability groups. Reader ability differences in processing letter identities were discussed in the context of current theories of reading acquisition.     

The Toronto Word Pool: Norms for imagery,concreteness, orthographic variables,and grammatical usage for 1,080 words

Imagery and concreteness norms and percentage noun usage were obtained on the 1,080 verbal items from the Toronto Word Pool. Imagery was defined as the rated ease with which a word aroused a mental image, and concreteness was defined in relation to level of abstraction. The degree to which a word was functionally a noun was estimated in a sentence generation task. The mean and standard deviation of the imagery and concreteness ratings for each item are reported together with letter and printed frequency counts for the words and indications of sex differences in the ratings. Additional data in the norms include a grammatical function code derived from dictionary definitions, a percent noun judgment, indexes of statistical approximation to English, and an orthographic neighbor ratio. Validity estimates for the imagery and concreteness ratings are derived from comparisons with scale values drawn from the Paivio, Yuille, and Madigan (1968) noun pool and the Toglia and Battig (1978) norms.     

Relation of age at onset to duration of episode in unipolar depression

The purpose of this study was to test the hypothesis that the duration of episodes of unipolar depression increases with age at onset. On the basis of elevated scores on a self-report depression measure, 2,020 persons were selected from a larger community sample to be interviewed and diagnosed using the Schedule for Affective Disorders and Schizophrenia-Research Diagnostic Criteria procedures. Of the 2,020 persons, 865 had a history of one or more episodes of unipolar depression. The potential effects of the following variables (singly and in interaction) on duration of episode were assessed by means of multiway frequency table analysis and chi-square: age at onset, sex of subject, interval since occurrence of the episode, and type of disorder (major vs. minor depressive disorder). The hypothesis that duration of episodes of depression increases with age at onset was not supported. Women were more likely to have multiple episodes, but did not have longer lasting episodes.     

Emotionality in selectively bred strains of rats mediates prior shock effects on escape-avoidance conditioning.

Rats of the Maudsley Reactive and Maudsley Non-reactive strains were given 25 trials of escape-avoidance conditioning after exposure to inescapable shock. Prior shock exposure (PSE) did not affect avoidance or escape latencies, but decreased the number of avoidances made by the Maudsley non-reactive animals and increased the number of their failures to escape. The results are interpreted as demonstrating an interference with the classical conditioning of a conditioned emotional response, through a reduction in the information content of the CS following PSE. The strain differences are interpreted as due to the non-reactive animals being especially sensitive to PSE.     

Computer control of memory experiments on a large-scale timesharing system

This paper describes a computer system for running verbal learning and memory experiments using a large-scale timesharing computer. Its application is illustrated by control programs used to set up, execute, and analyze a series of interactive free recall experiments. While limitations of timesharing systems for experimental control surely exist, they can often be removed by simple hardware or software. Further, a large machine can provide significant advantages in cost and software development over dedicated laboratory minicomputers. It is possible to obtain the advantages of both types of systems by introducing local intelligence to provide more precise timing and flexible control of experimental devices, while retaining the power and hardware and software resources of the large machine.     

Is "Blank" a suitable neutral prime for event-related potential experiments?

We report an experiment that evaluates whether BLANK or an unrelated prime is a more suitable baseline for assessing priming for an ERP study. Sixteen subjects performed a lexical decision task with a 1 s prime-target stimulus onset asynchrony. Increased amplitude for the N400 was observed for targets in the unrelated prime condition whereas targets in the BLANK prime condition evoked activity that was more like that in the related prime condition. Theoretically, we conclude that the N400 reflects semantic integration. Pragmatically, we conclude that the BLANK prime is a better neutral prime but that unrelated primes yield stronger N400 effects.     

Benjamin Franklin and shock-induced amnesia

Shock-induced amnesia received considerable attention after Cerletti popularized electroconvulsive shock therapy in the late 1930s. Yet, often overlooked is the fact that Benjamin Franklin recognized that passing electricity through the head could affect memory for the traumatic event. Franklin described his findings on himself and others in several letters from the mid-1700s, 2 of which were published in his lifetime. What he observed was confirmed in 1783 by physician Jan Ingenhousz, who was one of his correspondents. Although Ingenhousz had lost his memory for his electrical accident and was confused immediately afterward, he felt strangely elated and unusually sharp the next morning. Hence, he called for clinical trials with patients with melancholia who were not responding to more conventional therapies. After Franklin received Ingenhousz's letter, he also called for clinical trials. Neither man, however, tied the possible new cure for melancholia to the memory loss--nor did the operators that began to treat some patients with melancholia successfully with cranial shocks. Only much later would the amnesia be thought to be associated with the cure.     

Principles of early stopping of randomized trials for efficacy: a critique of equipoise and an alternative nonexploitation ethical framework

Recent controversial decisions to terminate several large clinical trials have called attention to the need for developing a sound ethical framework to determine when trials should be stopped in light of emerging efficacy data. Currently, the fundamental rationale for stopping trials early is based on the principle that equipoise has been disturbed. We present an analysis of the ethical and practical problems with the "equipoise disturbed" position and describe an alternative ethical framework based on the principle of nonexploitation. This framework acknowledges the need for balancing the dual ethical obligations of clinical research, the protection of human subjects and the generation of new medical knowledge. Based on this framework, we put forward a proposal to make early stopping guidelines more stringent under specified conditions. The temporary withholding of apparent benefits in certain circumstances is justified by achieving a fair contract with the research participants, one that protects them from undue harm and exploitation while reducing the many uncertainties surrounding new investigational treatments that arise when trials are stopped prematurely.     

Parsing surrounding space into regions

Surrounding space is not inherently organized, but we tend to treat it as though it consisted of regions (e.g., front, back, right, and left). The current studies show that these conceptual regions have characteristics that reflect our typical interactions with space. Three experiments examined the relative sizes and resolutions of front, back, left, and right around oneself. Front, argued to be the most important horizontal region, was found to be (a) largest, (b) recalled with the greatest precision, and (c) described with the greatest degree of detail. Our findings suggest that some of the characteristics of the category model proposed by Huttenlocher, Hedges, and Duncan (1991) regarding memory for pictured circular displays may be generalized to space around oneself. More broadly, our results support and extend thespatial framework analysis of representation of surrounding space (Franklin & Tversky, 1990).