Common features of fluency-evoking conditions studied in stuttering subjects and controls: an H(2)15O PET study

We used H(2)15O PET to characterize the common features of two successful but markedly different fluency-evoking conditions -- paced speech and singing -- in order to identify brain mechanisms that enable fluent speech in people who stutter. To do so, we compared responses under fluency-evoking conditions with responses elicited by tasks that typically elicit dysfluent speech (quantifying the degree of stuttering and using this measure as a confounding covariate in our analyses). We evaluated task-related activations in both stuttering subjects and age- and gender-matched controls. Areas that were either uniquely activated during fluency-evoking conditions, or in which the magnitude of activation was significantly greater during fluency-evoking than dysfluency-evoking tasks included auditory association areas that process speech and voice and motor regions related to control of the larynx and oral articulators. This suggests that a common fluency-evoking mechanism might relate to more effective coupling of auditory and motor systems -- that is, more efficient self-monitoring, allowing motor areas to more effectively modify speech. These effects were seen in both PWS and controls, suggesting that they are due to the sensorimotor or cognitive demands of the fluency-evoking tasks themselves. While responses seen in both groups were bilateral, however, the fluency-evoking tasks elicited more robust activation of auditory and motor regions within the left hemisphere of stuttering subjects, suggesting a role for the left hemisphere in compensatory processes that enable fluency. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) compare brain activation patterns under fluency- and dysfluency-evoking conditions in stuttering and control subjects; (2) appraise the common features, both central and peripheral, of fluency-evoking conditions; and (3) discuss ways in which neuroimaging methods can be used to understand the pathophysiology of stuttering.     

The Influence of Indirect Knowledge of Previous Performance on Ratings of Present Performance: The Effects of Job Familiarity and Rater Training

In a 2 × 2 × 2 crossed factorial design, trained or untrained subjects viewed a videotape and evaluated performance on either a familiar (college lecturer) or unfamiliar (salesperson) job. Prior to viewing the videotape, some subjects reviewed positive information about the ratee's prior performance, whereas other subjects did not review any prior performance information. To determine whether assimilation or contrast effects occurred, we compared ratings provided by subjects who reviewed positive information about prior performance with ratings provided by subjects who did not review any prior performance information. A three-way interaction was obtained. Ratings of performance on the familiar job by untrained or trained subjects revealed only a small assimilation effect. However, when rating performance on the unfamiliar job, a large assimilation effect was observed among untrained subjects, whereas a large contrast effect was observed among trained subjects. The results indicate that rater error training may reverse, rather than reduce or eliminate, rating errors that arise from knowledge of a ratee's prior performance. Implications for further understanding and reducing assimilation and contrast effects are discussed.     

Establishing a Descriptive Database for Teachers with Aggressive Students

While establishing a database that describes students' aggressive behaviors and the conditions present at the time of occurrence, we discovered a variety of definitions of aggression in the literature. This lack of consistency limits the information provided to teachers working with the frequent problem of violence. We propose an inclusive and verifiable definition of aggression gleaned from experience and the literature. The definition incorporates verbal, paraverbal, nonverbal, and physical aggression. Validation is presented from the literature, and from 39 practicing teachers who used the definition to categorize 659 target behaviors. The teachers' level of agreement with the authors' categorization was 93% (median).     

The effect of affirmative action on attributions about minority group members

In the first study subjects were given information about an applicant to graduate school and asked to rate his qualifications. The information experimentally varied (a) whether the school had an affirmative action policy, (b) the ethnicity of the applicant, and (c) whether the applicant was accepted or rejected. Based on Kelley's discussion of the discounting and augmentation principles, it was predicted that the minority applicant would be rated as less qualified when the university was committed to an affirmative action program. The reverse pattern was predicted for the non-minority applicant. The results supported the first prediction but not the second. Experiment 2 was designed to eliminate alternative interpretations of the data and the same results were found. Possible interpretations for the failure of affirmative action in affecting the ratings of nonminority applicants are discussed.     

Social problem-solving skills in boys with conduct and oppositional defiant disorders

The current study compared the social problem-solving skills of a clinic-based sample of 30 boys diagnosed with conduct disorder (CD) and 25 boys diagnosed with oppositional defiant disorder (ODD). Past research has indicated that contextual factors influence children's social problem-solving; thus, three hypothetical conflict situations (i.e., child-child, teacher-child, and parent-child) and situations which differed by degree of negative intent of the provocateur (i.e., hostile vs. Ambiguous intent) were examined. Problem-solving strategies were aggregated into three broad dimensions: 1) aggressive/antisocial solutions; 2) nonverbal-nonaggressive solutions; and 3) verbal-nonaggressive solutions. Compared to ODD boys, CD boys proposed more aggressive/antisocial solutions in parent-child conflicts when parental intent was ambiguous and in teacher-child conflicts regardless of intent. Compared to ODD boys, CD boys proposed fewer verbal-nonaggressive solutions in child-child conflicts. The implications of these findings for treatment intervention with CD and ODD boys were discussed. Aggr. Behav. 23:457–469, 1997. © 1997 Wiley-Liss, Inc.     

Working Together with God: Religious Coping,Perceived Discrimination,and Hypertension

This study examined the relationships of perceived discrimination and religious coping with hypertension in a sample of Black and White Seventh-day Adventists. Data come from a community-based sample of 6128 White American, 2253 African American and 927 Caribbean American adults (67% women; mean age = 62.9 years). Results indicate lifetime unfair treatment was significantly associated with hypertension regardless of race/ethnicity. Positive religious coping was associated with lower odds of hypertension and did not interact with unfair treatment. Both positive and negative religious coping were indirectly associated with increased hypertension risk through an increase in perceived discrimination.

     

The challenge of merging: merger patterns, premerger status, and merger support

Employees of merging organizations often show resistance to the merger. The employees' support depends on the companies' premerger status and on the merger pattern. Based on an intergroup perspective, three studies were conducted to investigate the influence of premerger status (high, low) and merger pattern (assimilation, integration-equality, integration-proportionality, transformation) on participants' support for a pending organizational merger. Students (Study 1) and employees (Study 2) had to take the perspective of employees of a fictitious merging organization. Study 3 investigated students' perceptions of a potentially pending university merger using a 2 (status) x 3 (merger pattern: assimilation, integration-equality, integration-proportionality) design. Across all studies, the low-status group favored integration-equality and transformation whereas the high-status group preferred integration-proportionality and assimilation. Perceived threat mediated the effects. Legitimacy was a stronger mediator for effects of the low-status group.     

Speech perception deficits in Parkinson's disease: underestimation of time intervals compromises identification of durational phonetic contrasts

Besides motor, vegetative, and cognitive signs, patients suffering from Parkinson's disease (PD) may show distinct perceptual deficits such as underestimation of time intervals extending across several seconds. Assuming this impairment also to affect the domain of tens of milliseconds, disrupted encoding of the acoustic speech signal with respect to segment durations conveying linguistic information must be expected. To test this hypothesis, 10 PD patients and matched controls performed an identification task using a series of 10 stimuli derived from the utterance "Boten" (/bo:tn/, 'messengers'; produced with nasal plosion) by exclusive manipulation of occlusion length (110-20 ms in steps of 10 ms). Under these conditions, word-medial silence cues the voicing category of the respective stop consonant. Seven PD subjects showed normal identification curves, i.e., categorized the shortest and longest stimuli with high probability each as the minimal pair cognates "Boden" and "Boten," respectively. In contrast, the remaining three patients labeled all items across the complete range of occlusion lengths as "Boden." A subsequent experiment found a horizontal shift of the identification curves toward larger signal durations (> 120 ms) in these three subjects. Bilateral cerebellar degeneration has been found to yield a different response pattern, i.e., near-chance level of performance. Considering recent information-processing models of scalar interval timing, striatal disorders seem to slow down an oscillatory pacemaker, whereas cerebellar dysfunctions may impair comparison of measured durations with stored reference memory traces.