An examination for construct bias in the WISC-R across socioeconomic status

The ten subtests comprising the Wechsler Intelligence Scale for Children —Revised (WISC-R) were independently factor analyzed for middle and low socioeconomic status children. Two factors described the structure of the test in both cases. These two factors corresponded quite closely to the Verbal Comprehension and Perceptual Organization factors usually reported for the WISC-R. After testing for the equivalence of covariance matrices between the two socioeconomic status groups, coefficients of congruence between the factors were calculated. These coefficients indicated equivalence in the constructs being measured across the two groups.     

Graphing multivariate data with Chernoff''s faces

Chernoff's faces is one of several icon graphics routines accessible through the SYGRAPH module available through SYSTAT Inc. SYSTAT is a very sophisticated statistics package that has been previously reviewed in the Journal of School Psychology (Roberts, D. M. JSP 25, 313–318, 1987). SYSTAT and SYGRAPH are available for both the IBM PC and the Apple Macintosh computers. The output from this example was produced with SYSTAT 5.1 on a Macintosh computer.     

Distraction effects in tasks of varying difficulty: Methodological issues in measuring development of distractibility

Effects of distraction on 5- and 8-year-old children's performance on a short-term memory task were examined. Tasks at three difficulty levels were employed to determine whether a floor effect could account for the lack of an age difference reported in an earlier study. A floor effect does not appear to be a key factor; the absolute amount of performance decrement was roughly equal for the two ages here regardless of task difficulty, and performance was well above chance under all conditions. The children adapted somewhat to the presence of distraction as shown in greater performance impairment for the first trial under distraction than for remaining trials. Use of a proportional, rather than an absolute, decrement index was considered, and the relevance of the present data to this issue was discussed.     

Spacetime and the abstract/concrete distinction

Earlier versions of this paper were read at seminars at The University of North Carolina at Chapel Hill, at the North Carolina Philosophical Society meeting in February 1986, and at the Eastern Division meeting of the American Philosophical Association in December 1986. I am grateful for the comments I received on those, and other less formal, occasions. My greatest debts are to Catherine Elgin, David Lewis, William Lycan, Michael Resnik, Jay Rosenberg, and George Schlesinger.     

Low-cost laboratory computing: Microcomputers in British psychology departments

Over 25% of the 80 British psychology departments use microcomputers. This paper summarizes the types of processor, level of system integration, applications, and problems of these users. The Motorola 6800 is by far the most popular processor, but there is a growing number of Z-80 users. Useful microcomputers have been developed from chips, single-board evaluation kits, hobby products, and manufacturers’ development systems. Applications include front-end processing, networking, and stand-alone uses for data logging, process control, and the development of intelligent laboratory tasks. Emphasis is placed on the need to match system packaging and support facilities to the application.     

Uncertainty about the rest of the sentence

A word-by-word human sentence processing complexity metric is presented. This metric formalizes the intuition that comprehenders have more trouble on words contributing larger amounts of information about the syntactic structure of the sentence as a whole. The formalization is in terms of the conditional entropy of grammatical continuations, given the words that have been heard so far. To calculate the predictions of this metric, Wilson and Carroll's (1954) original entropy reduction idea is extended to infinite languages. This is demonstrated with a mildly context-sensitive language that includes relative clauses formed on a variety of grammatical relations across the Accessibility Hierarchy of Keenan and Comrie (1977). Predictions are derived that correlate significantly with repetition accuracy results obtained in a sentence-memory experiment (Keenan & Hawkins, 1987).     

The effects of the dopamine D1 receptor antagonist SCH23390 on memory reconsolidation following reminder-activated retrieval in day-old chicks

This series of experiments examined the involvement of the dopamine D1 receptor antagonist, SCH23390, on memory reconsolidation following reminder-activated retrieval. Day-old male New HampshirexWhite Leghorn chicks were trained on a single trial passive avoidance task. A dose of 0.5 mg/kg of SCH23390 was administered subcutaneously 5 min before reminder trials, which were presented at 30, 60, and 90 min following training. Memory deficits were observed when reminder trials were presented at 30 and 60 min following training, but not when a reminder was presented at 90 min. No effect on memory retention was observed when reminder trials were not presented, suggesting that reconsolidation mechanisms were both contingent on the presentation of the reminder and independent of the consolidation process. Following a reminder presented at 60 min post-training, deficits in memory retention emerged between 45 and 60 min. The deficit was prolonged, lasting for up until 48 h after reminder presentation. The results indicate an important role for the D1 receptor in reconsolidation processes.     

Variations in working memory capacity predict individual differences in general learning abilities among genetically diverse mice

Up to 50% of an individuals' performance across a wide variety of distinct cognitive tests can be accounted for by a single factor (i.e., "general intelligence"). Despite its ubiquity, the processes or mechanisms regulating this factor are a matter of considerable debate. Although it has been hypothesized that working memory may impact cognitive performance across various domains, tests have been inconclusive due to the difficulty in isolating working memory from its overlapping operations, such as verbal ability. We address this problem using genetically diverse mice, which exhibit a trait analogous to general intelligence. The general cognitive abilities of CD-1 mice were found to covary with individuals' working memory capacity, but not with variations in long-term retention. These results provide evidence that independent of verbal abilities, variations in working memory are associated with general cognitive abilities, and further, suggest a conservation across species of mechanisms and/or processes that regulate cognitive abilities.