Evaluating a computational model of perceptual grouping by proximity

A formal approach to the phenomenon of perceptual grouping by proximity was investigated. Grouping judgments of random dot patterns were made by the CODE algorithm (van Oeffelen & Vos, 1982) and several related algorithms, and these judgments were compared with subjects’ grouping judgments for the same stimuli. Each algorithm predicted significantly more subject judgments than would be expected by chance. The more subjects agreed on how a given dot pattern should be grouped, the more successful was the algorithms’ ability to match the judgments for that pattern. CODE predicted significantly fewer subject judgments than did some of the other algorithms, largely because of its overemphasis on the extent of interactivity among dots as they are being grouped.     

Coming to terms with stress: Effects of stress location in sentence processing

The purpose of this research was to determine the role of syllabic stress in language processing during the early on-line processing of speech and later in the representation of a sentence in memory. Experiment 1 used a syllable monitoring task while Experiment 3 used a probe task in which subjects heard a sentence and then were asked to determine whether a probe syllable had occurred in the sentence. In the monitoring task, stressed syllables were detected more rapidly in word-initial position, but unstressed syllables were detected more rapidly in word-final position. Stress facilitation in initial syllables was strongly related to high relative F0, but not to changes in perceived vowel quality as assessed in Experiment 2. This pattern is interpreted as evidence that lexical stress is used on-line to guide lexical access and/or lexical segmentation. The probe task of Experiment 3 showed stress facilitation in both positions, indicating that stress is independently retained in the postperceptual representation of a sentence.The research reported in this paper was supported by grant 80-0416 to Harvard University (Peter C. Gordon, Principal Investigator) from the Air Force Office of Scientific Research Life Sciences Directorate. We thank Chris Thurber for his extensive and competent assistance in testing subjects and making acoustic measurements, and Jay Rueckl for comments on an earlier version of this paper     

Images of black women among anglo college students

Previous research on popular images of women and of minority groups has looked almost solely at images of minority men and of white women. This article presents survey data on images of black women among 256 white non-Hispanic college undergraduates, using a modified Katz/Braly scale. The article explores the nature, distribution, correlates, and emotional evaluations of these images and the implications of these images for black women's lives. Images of black women differed substantially from those of American women in general. Most commonly, black women were characterized as loud, talkative, aggressive, intelligent, straightforward, and argumentative. In addition, students rated positive traits less positive and negative traits less negative when exhibited by black women than by American women in general, apparently because of their expectations for black women's behavior.This paper has benefited from the comments of Verna Keith, Wade Smith, and, most especially, Mary Benin. This research was partially supported by Arizona State University Women's Studies Summer Research Awards Program.     

Are hyperactive children deficient in attentional capacity?

A dual task was used to study attentional capcity in three groups: in 6- to 12- year- old boys with attention deficit disorder plus hyperactivity (ADDH) or with ADDH and conduct disorder, and in normal children. Subjects performed a primary-choice reaction-time task first without and then with a secondary task that also required a response. Our prediction that the reaction time of ADDH subjects to the secondary task would increase more with increasing temporal overlap of the primary and secondary stimuli, if they were deficient in capacity, was not supported. However, the performance of ADDH subjects on the primary task deteriorated more than that of control subjects with the introduction of the secondary task, indicating a greater concurrence cost or a different allocation policy. Moreover, ADDH subjects had longer reaction times to the secondary task, indicating greater refractory effects or difficulty shifting capacity from primary- to secondary-task processes.The authors would like to acknowledge the support of the Ontario Mental Health Foundation and the assistance of Diane Chajczyk. This paper was prepared with the assistance of Medical Publications, The Hospital for Sick Children, Toronto, Ontario.     

Perfectionism and Suicide Ideation in Adolescent Psychiatric Patients

This study was conducted to examine the relations between dimensions of perfectionism and suicide ideation in an adolescent psychiatric sample. A sample of 66 adolescents from an inpatient psychiatric facility completed the Child and Adolescent Perfectionism Scale, the Child's Hopelessness Scale, and the Suicide Ideation Questionnaire. Overall, the results indicated that socially prescribed perfectionism was associated with greater suicide ideation and that it, along with hopelessness, accounted for unique variance in suicide ideation scores. The findings are discussed in terms of their practical and theoretical significance as well as their consistency with similar research with adults.     

Pronominalization and discourse coherence,discourse structure and pronoun interpretation

Two self-paced reading-time experiments are reported that examine the time course of pronoun interpretation processes based on local discourse structure and on world knowledge. The characterization of local discourse structure is based on recent work on centering, which provides a specific formulation of how the ways in which sentences make reference to common entities determines the coherence of discourse segments and how discourse structure influences interpretation of ambiguous pronouns. The results of the first experiment show that readers generate a default interpretation of a pronoun based on features of local discourse structure, and that that default interpretation is later confirmed or overridden by knowledge-based processes. The results of the second experiment show that local discourse structure continues to influence pronoun interpretation even when the semantic information that ultimately compels interpretation occurs before the pronoun. These results support the view that processes acting on local discourse structure play a powerful role in guiding language comprehension.     

BY ANY MEANS NECESSARY: JOHN LOCKE AND MALCOLM X ON THE RIGHT TO REVOLUTION*

Many will ask what Harlem finds to honor in the stormy, controversial and bold young captain. And we will smile. And we will answer and say unto them: Did you ever talk to Brother Malcolm? Did he ever touch you? Did you have him smile at you? Did he ever do a mean thing? Was he ever himself associated with violence or any public disturbance? For if you did, you would know him and if you knew him you would know why we must honor him.     

The stability of depressive symptoms in college students: An empirical demonstration of regression to the mean

In a recent paper, Vredenburg, Flett, and Krames (1993) hypothesized that the apparent instability of depressive symptom scores in college students may be due, in part, to the phenomenon known as statistical regression to the mean. This statistical principle was demonstrated in the current study. A sample of 183 university students completed the Beck Depression Inventory (BDI) at two timepoints separated by a 3-month interval. Consistent with past results, analyses revealed substantial changes in symptom scores over time with decrements being evident among many subjects with elevated symptom scores at Time 1. Examination of the amount of change over time in BDI scores indicated a pattern of findings that approximated the regression to the mean phenomenon. Statistical tests confirmed that regression to the mean accounted for a significant amount of the change in symptom scores over time. The implications of these findings are discussed in terms of the nature of depressive symptoms in students and the inappropriateness of assigning subjects to depressed or nondepressed groups on the basis of elevated scores on a self-report measure.