Research on the effects of numerical control (NC) machining on the skills of machinists presents mixed results. Interviews with a small group of machinists experienced in both conventional and NC matching suggest seven major factors that affect whether NC automation changes the overall skill level. The deskilling hypothesis is not supported by…

This study reports intraindividual variations in the semantic and syntactic complexity of language and in the linguistic errors produced by mildly and moderately impaired adult aphasic subjects (N=10) in different communication contexts. Aphasic patients exhibited at least as many linguistic variations as controls in response to changing…

The Ravens Standard Progressive Matrices Test was administered to 48 subjects who then performed a card-sorting task under single- and competing-task conditions. Hick's Law and the Roth-Jensen procedure were used in task development. Complexity should have a more central role in speed of processing models of intelligence than ability to divide…

Involving children three and four years of age, studies examined the basis for the difficulty of discriminating between left-right orientations of a shape in standard two-choice task. It was concluded that difficulty of left-right judgments lies in the cognitive demands of the task and is to be understood in the same terms as other problems in…

Distractible elementary students (N=44) were assigned to one of four experimental conditions, reflecting manipulations of reinforcement and task difficulty. For difficult tasks, students assigned to contingencies for correct academic performance alone were off-task more and scored significantly lower in academic performance than Ss receiving…

The influence of changes in wording of simple arithmetic problems without affecting semantic structure on the level of difficulty for primary-grade students was investigated. Data analysis produced results that rewording the problem so that the semantic relations are made more explicit facilitates the construction of an appropriate mental…

Three experiments investigated the dynamics of human infant visual fixation. Results showed that, over a series of trials, four-month-olds fixate longer on a complex than on a simple stimulus. Findings challenge prevailing cognitive-schema theories as a complete account of the dynamics of infant visual fixation. A two-process theory that accounts…

To determine how hard it is for computers to solve problems, researchers have classified groups of problems (polynomial hierarchy) according to how much time they seem to require for their solutions. A difficult and complex proof is offered which shows that a combinatorial approach (using Boolean circuits) may resolve the problem. (JN)

Concludes that, in the organizations studied, complexity cannot be satisfactorily predicted or fully understood without reference to the economics of scale, but that it is neither theoretically convincing nor statistically demonstrable that size in itself is the major determinant of formalization. (Author/JN)

"The usefulness of a structural analysis of pretest items in designing an instructional system is illustrated by the application of this technique to 100 addition computation problems. (Author)