Left-hemisphere language lateralization in bilinguals: use of the concurrent activities paradigm

Previous visual and auditory lateralization studies have demonstrated that the languages of bilinguals are lateralized to the left hemisphere to the same extent as in monolingual controls (C. Soares & F. Grosjean, 1981, Perception and Psychophysics, 29, 599-604; C. Soares, 1982, Neuropsychologia, 20, 653-659). The present study tested the same group of Portuguese-English bilinguals and a group of English-speaking monolinguals on a series of concurrent activity, or time-sharing, tasks. Greater levels of disruption in finger tapping with the right hand than with the left hand occurred during the performance of those tasks which required overt speech production, and this for both bilinguals and monolinguals. As in the previous studies, there were no lateralization differences across the bilinguals' two languages or between bilinguals and monolinguals. Thus, further evidence for equal levels of left-hemisphere dominance for language in bilinguals and monolinguals was provided by the use of the concurrent activities paradigm.     

Right-hemispheric language evidence from cortical stimulation

While the left-hemispheric dominance for language in most right-handers is unquestionable, clinical observations suggest that the right, nondominant hemisphere has a considerable capacity for language. Under certain neuroanatomical conditions, the right-hemispheric capacity becomes functional and, thus, measurable. This study focuses on evoked language responses during electrical stimulation of the right hemisphere in three left-dominant patients undergoing temporal lobe resections for medically intractable seizures.     

Cerebral organization of oral and signed language responses: case study evidence from amytal and cortical stimulation studies

A normally hearing left-handed patient familiar with American Sign Language (ASL) was assessed under sodium amytal conditions and with left cortical stimulation in both oral speech and signed English. Lateralization was mixed but complementary in each language mode: the right hemisphere perfusion severely disrupted motoric aspects of both types of language expression, the left hemisphere perfusion specifically disrupted features of grammatical and semantic usage in each mode of expression. Both semantic and syntactic aspects of oral and signed responses were altered during left posterior temporal-parietal stimulation. Findings are discussed in terms of the neurological organization of ASL and linguistic organization in cases of early left hemisphere damage.     

Detection of color in rotating objects by infants and its generalization over changes in velocity.

In three experiments, infants between 8 and 20 weeks of age were familiarized during habituation trials to either a stationary or revolving patterned cylinder (Experiment 1) or to the same object when it was revolving at one of two angular velocities (Experiments 2 and 3). In the postfamiliarization trials, angular velocity was changed with the color of the pattern either the same as or different from that in the familiarization trials. The results showed that the infants were not only sensitive to movement and changes in velocity but to the color of the moving pattern. Furthermore, this response to color generalized across changes in angular velocity. These findings indicate that a necessary condition for identity constancy, detection of an object property with object transformations, is present between 8 and 20 weeks, prior to the stage of manual manipulation of objects. A number of subsidiary findings concerning movement discrimination at 55 and 100 cm viewing distances by 11- and 17-week-old infants are also described.     

A within-subject analysis of stimulus control therapy with severe sleep-onset insomnia.

Stimulus control, a behavioral technique designed to reduce sleep difficulties, has been demonstrated to be effective when compared with control procedures. These comparisons, mainly involving between-subjects analyses, have neglected the contribution of the stimulus control procedure to the production of clinically significant amelioration of sleep dysfunction. In contrast, the present within-subjects experiment was conducted to assess the capability of stimulus control to produce clinically relevant reductions in multiple measures of sleep disturbance. A comparison with the credible placebo procedure indicated that the stimulus control techniques reduced subjects' sleep onset latency to a mean latency below 30 min per week. Additionally, sedative-hypnotic usage was greatly reduced.     

Effect of thought-stopping on thoughts,mood and corrugator EMG in depressed patients

The immediate effects of thought-stopping applied to depressive thoughts were compared to those of a control procedure in a group of depressed psychiatric day-patients. Thought-stopping had only a weak effect on average in reducing the frequency of depressive thoughts, and no significant effects on depressed mood or corrugator EMG. A small significant effect on anxious mood appeared related to non-specific factors. The results raise the possibility that thought-stopping may have little specific effect in reducing the frequency of unwanted thoughts. Corrugator EMG was significantly related to the frequency of spontaneously occurring depressive thoughts both between and within subjects.     

Feature selection and classification: A developmental study

Two hundred and thirteen children between the ages of 4 and 16 sorted 30 complex objects freely into groups. These were either schematic faces, schematic imaginary animals, or histoform patterns and were constructed from 9 independently and continuously varying features, each with 10 levels. The three sets were equivalent in terms of underlying numerical structure. A new method of analysis of the groups formed yielded the following direct measures of subjective organization in the sorting of each child: the number of features used in sorting, the accuracy of sorting, and the number of independent dimensions of classification. Both the material and the analysis of sorting were devised on the assumption that only some of the component features of complex objects are used for classification, while others are ignored. Sorting performance differed markedly both with age and with different types of material. The improvement in sorting ability with age, except for the youngest children, could be attributed to an increase in the number of features used rather than an improvement in the accuracy of use. In contrast, the poor sorting of histoform patterns as opposed to faces and animals was due to a low level of sorting accuracy. The basic results on the development of classification confirmed previous studies, and hence suggest that it is valid to consider feature selection as a basic component of classification.     

Competitive behavior: A manifestation of motivation for ability comparison

Social comparison theory predicts that when the person is uncertain about the level of his ability, he may seek comparison information through competitive behavior. This derivation, however, has never been directly tested. An experiment is reported in which the level of the subject's uncertainty about his competence was manipulated and subsequent measures of his competitive motivation and behavior were obtained. The data indicate that higher levels of uncertainty do lead to higher levels of motivation and competition, but only under conditions that minimize threat to self-esteem.     

Commitment,ego-involvement,and resistance to attack

Subjects with initially extreme or moderate positions (based on a median split) recorded a consonant speech under public, private, or no commitment and later received a strong, mild, or no attack on their position. Extremes were more ego-involved in terms of wider latitudes of rejection, narrower latitudes of non-commitment, and greater resistance to attack, relative to moderates. Commitment had no effect for extremes, suggesting a ceiling effect on changes in the latitudes and resistance to attack for initially high levels of ego-involvement. For moderates, commitment resulted in narrower latitudes of noncommitment, wider latitudes of rejection (greater rejection of discrepant positions), and greater resistance to attack, suggesting that commitment may elevate ego-involvement with the issue. Commitment and ego-involvement may increase the salience of one's attitude position in later situations, thereby increasing the probability of attitudeconsistent behavior.     

The role of the perioral reflex in lip motor control for speech.

The analysis of spinal and brainstem reflexes has been shown to be a useful method of quantifying the various inputs to motoneuron pools involved in voluntary motor control. This work is selectively reviewed as a background to a discussion of the role of the perioral reflex in lip motor control for speech. Data on the sensorimotor innervation of the lips and the static and dynamic properties of the perioral reflex are presented in support of the notions that (1) perioral reflex analysis provides a viable technique for analyzing brainstem excitability changes underlying lip muscle contraction for speech, and (2) the perioral reflex loop is an important functional element in lip motor control for speech.