Cortical potentials evoked by confirming and disconfirming feedback following an auditory discrimination

Vertex potentials elicited by visual feedback (signals following an auditory intensity discrimination have been studied with eight Ss. Feedback signals which confirmed the prior sensory decision elicited small P3s, while disconfirming, feedback elicited P3s that were larger. On the average, the latency of P3 was also found to increase with increasing disparity between the judgment and. the feedback information. These effects were part bf an overall dichotomy in waveshape following confirming vs disconforming feedback. These findings are incorporated in a general model of the role of P3 in perceptual decision making.     

The development of retrieval strategies in young children

Two incidental memory tasks were given to 3.5–6.5 yr old children to test for an age increase in the tendency to use a simple indirect retrieval strategy when direct retrieval efforts do not suffice. In both tasks, pictures of people were paired with very closely associated toy objects (e.g., farmer—toy tractor), and the indirect retrieval strategy consisted of thinking to use one member of the pair as a cue to the recall of the other, e.g., turning over the visible but facedown pictures and using them as retrieval cues for the toys. Support for the predicted age trend was obtained in one of the two tasks. It was suggested that the development of retrieval skills in children may show some parallels with that of storage skills.     

Terminating and exhaustive search in lexical access

Two experiments which test predictions derived from the assumption that lexical access involves a search process are reported. In the first experiment, test items must be classified as ambiguous or unambiguous, and in the second experiment, they are classified according to their syntactic properties. In both experiments, it is shown that when the target of the search is a nonexistent entry, an exhaustive search is involved, even though the test items are words. Further, in these conditions, frequency of occurrence is no longer related to decision time, as it is in lexical decision experiments. It is concluded that the search model adequately explains the procedure whereby the most common meaning of a homograph is accessed, but that the less common meaning is accessed in some completely different manner.     

An extended class of matched pairs tests based on powers of ranks

A large class of rank tests, which includes the familiar sign test and the Wilcoxon signed-ranks test, is described and discussed. This class of distribution-free tests provides a flexible basis for testing research hypotheses of various forms. Exact small sample and approximate large sample procedures are considered. Applications of these procedures are presented, including simple numerical examples.The authors wish to acknowledge the constructive comments by the reviewers.     

Defects of immediate memory in Broca's and conduction aphasia

It has been suggested that the repetition defect seen in conduction aphasia is caused by an auditory immediate memory defect. The purposes of this study were the following: to ascertain whether the finding of an auditory immediate memory defect in conduction aphasia could be replicated, to ascertain whether Broca's aphasics have a similar type of immediate memory defect, and to ascertain whether a relationship exists between immediate memory and comprehension of spoken language. Digits were either spoken or presented visually to Broca's and conduction aphasics. An analysis of span scores reveals that within each group there were no significant differences between the modes of presentation or the response modes. There were no significant differences between the aphasic groups. Comprehension of spoken language significantly correlated with digit span scores.     

Development of an on-line management information system for community mental health centers

An on-line computerized management information system has been developed at the Salt Lake City VA Hospital and is currently being implemented at Salt Lake Community Mental Health Center. An introduction to this system, including systems design and procedures for development, are presented. The advantages of on-line technology as compared to batch processing technology are also discussed.