Parameters for vowel substitutions in Broca''s aphasia

Most phonological investigations of aphasic speech have focused on consonants. In this study, the vowel substitutions of five English-speaking Broca's aphasics were investigated with respect to several major explanatory hypotheses. An important possible motivating factor for aphasic substitutions, phonological environment, is an unlikely origin for these errors, since most substitutions occur along the paradigmatic axis. Another prominent hypothesis, markedness, also has no predictive power for the data of this sample. However, an analysis of the five Chomsky and Halle (1968, (The Sound Pattern of English), New York: Harper and Row) vowel features indicates that the two features for vowel height are selectively impaired: There is a strong tendency for lower vowels to replace higher targets. Moreover, the substitution sounds tend to be close to their target sounds along the height axis. Four possible hypotheses are advanced to account for this consistent lowering tendency.     

Neuroelectrical correlates of hemisphere and handedness factors in a cognitive task

Principal-components analysis was performed on a set of averaged evoked potentials in order to extract components of cerebral activity functionally related to hemisphere, handedness, processing task, and stimulus feature variables. Eight such components were isolated. Degree of dextrality, hemispheric differences, and cognitive operations in processing distinct stimulus characteristics were identified as reflected in functionally distinct components of brain activity.     

Career stages: A partial test of Levinson's model of life/career stages

This study purports to test a theory of life and career stages developed by Daniel Levinson and his associates. The theory suggests four distinct stages between ages 20 and 45 each with their own developmental tasks and related behaviors and attitudes. Subjects (759 managerial, professional, and technical employees) were selected randomly from levels and departments of a major public sector employer in the midwest United States. The measure of career stage asked respondents to indicate whether they had passed through, were still in, or had not yet reached each stage as operationalized by a short vignette. Attitudinal and behavioral measures were abstracted from previously developed instruments. Only moderate support for the theory was found with little or no evidence to support the age-linked notion of these stages. Stages were found to be discriminable in terms of certain attitudes (upward mobility, career and overall job satisfaction, and job commitment) as predicted. Suggestions are given for improvements in measurement, research design, and theory refinement.     

The use of a self-control package to enhance temporal generality of a parent training program

The purpose of the present study was to examine the effectiveness of a self-control package in enhancing temporal generality of a parent training program. Sixteen mothers and their clinic-referred noncompliant children were assigned to either a parent training alone group, or a parent training plus self-control group. All mother-child dyads were treated individually by teaching the mother to reward compliance and other prosocial behavior, and to use time-out for noncompliance. In addition, mothers who also received self-control training learned to self-monitor their use of their new parenting skills and to reinforce themselves for use of the skill during a 2 month follow-up period. Assessment consisted of four home observations by independent observers prior to treatment, after treatment, and at a 2 month follow-up. The data indicated that the children in the parent training plus self-control group were significantly more compliant and less deviant at the 2 month follow-up than the children in the parent training alone group. Parental behavior did not differ between the two groups at the follow-up.     

A feature-integration theory of attention

A new hypothesis about the role of focused attention is proposed. The feature-integration theory of attention suggests that attention must be directed serially to each stimulus in a display whenever conjunctions of more than one separable feature are needed to characterize or distinguish the possible objects presented. A number of predictions were tested in a variety of paradigms including visual search, texture segregation, identification and localization, and using both separable dimensions (shape and color) and local elements or parts of figures (lines, curves, etc. in letters) as the features to be integrated into complex wholes. The results were in general consistent with the hypothesis. They offer a new set of criteria for distinguishing separable from integral features and a new rationale for predicting which tasks will show attention limits and which will not.     

Effects of neutral and positive stimuli on stuttering: “Calling attention to stuttering” revisited

This study investigated the effects of presumably positive and neutral response-contingent stimuli on the occurence of stuttering. Eight adult stutterers spoke spontaneously during a 60-min experimental session, which was divided into three 20-min periods. During Condition I no stimuli were delivered. During Condition II a digital counter and a pair of yellow lights were activated each time the subject stuttered. During Condition III these same response-contingent stimuli were delivered, but with the additional factor that the subject would earn 5¢ each time the counter moved forward and the lights were illuminated. Conditions II and III were counterbalanced across subjects. The experimenter was unaware of which of the two contingencies were operative during Conditions II and III. Results showed no significant changes in occurence of stuttering due to either response-contingent stimulus. A discussion of theoretical and experimental implications is given.     

Some effects of lick-contingent delays on the development of schedule-induced polydipsia

Experiments 1 and 2 examined the effects of various durations of lickcontingent delays of reinforcement on the development of schedule-induced polydipsia. Food was provided every 1 min in the absence of licking. Delays of 1 min or more effectively disrupted the development of the licking behavior. In Experiments 3 and 4 a lick-contingent stimulus was provided in addition to the delay of food delivery. A light, which was turned on by a lick and turned off by food, greatly enhanced the development of polydipsia under delays that had previously prevented such development. A tone proved less effective than the light in promoting the development of polydipsia. Adventitious reinforcement and conditioned punishment explanations of these results were considered. A distinction was drawn between the mechanism responsible for the development of schedule-induced behavior and that responsible for its maintenance.     

Cognitive task effects on hemispheric blood flow in humans: Evidence for individual differences in hemispheric activation

Evidence from two indirect measures of hemispheric activity, EEG α and conjugate lateral eye movements, has pointed to the existence of individual differences in hemispheric activation. Results from a more direct indicator of hemispheric activity, regional cerebral blood flow as measured by the ¹³³Xe inhalation method, show that such individual differences can be detected in the distribution of blood in the two hemispheres and that the amount of increase in blood flow in the right relative to the left hemisphere is correlated with performance on a spatial task. These results corroborate and extend the findings from the EEG and eye movement studies and suggest that the dimension of individual differences in hemispheric activation may exert significant influence on cognitive performance and on problem-solving strategies.