A comparison of multiple versus single examples of the correct stimulus on task acquisition and generalization by persons with developmental disabilities

In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.     

Event-related brain potentials elicited by rhyming and non-rhyming pictures differentiate subgroups of reading disabled adolescents

Event-related brain potentials were recorded while disabled adolescent subjects read and judged whether two sequentially presented pictures had names that rhymed. Subjects with relatively good phonetic skills displayed an N400 priming effect, i.e., a significant reduction in the amplitude of the negative peak, occurring approximately 400 msec post-stimulus, for pictures with names that rhymed with preceding pictures as compared with pictures that had names that did not rhyme with the prime. No such effect was evident for subjects with relatively poor phonetic skills. This lack of an N400 priming effect provides evidence for a reduction in neural capacity and/or activation during phonological processing in the subjects with poor phonological skills. Demonstrating the N400 priming effect to be stronger in one group of reading disabled subjects, compared to another, supports the position that specific subtypes of reading disability exist. In addition to the stronger N400 priming effect, the phonetically stronger group also exhibited an enhanced negativity, from 700 to 1,000 msec after target stimulus onset, compared to phonetically inferior subjects. This finding replicates earlier work and possibly reflects a higher level of confidence in the group with better phonetic skills.     

What shall we do with Norman? An experiment in communal discernment.

We were a group of Christian friends searching for affirmations that lay at the heart of our faith and reached to the limits of our existence and moral authority. As we have reflected on our role in deciding whether and to what extent we could assist in allowing our terminally ill friend, seventy-nine-year-old, Norman to die, we were deeply troubled by the moral ambiguity of our involvement. Through a careful process of authority through communal discernment, our responsibility for Norman became clear: we were to assist him in living the life he embraced in baptism -- a life which included a destiny that was conformed to the crucified and risen one. That was not the destiny we chose for Norman; it was the destiny he owned. We recognized with Norman that our lives are not our own to be guided by autonomy and liberty, but rather to be lived for the glory of Jesus the Christ.     

Fourier analysis of movement patterns in pigeons

Fourier analysis describes the amount of variation in a time series by partitioning it into sinusoids of different amplitudes and wavelengths and quantifying the extent to which these waves are synchronized. The importance of a given wave is represented by its contribution to the explained variance of the time series. To illustrate its potential application to the study of movement, Fourier analysis was used to quantify the movement patterns of 2 pigeons on a variable-interval (VI) and a variable-time (VT) schedule of reinforcement. For comparison, the movements of 2 pigeons that did not receive reinforcement were similarly analyzed. Characteristic frequencies were higher during VI than during VT, and relatively low during nonreinforcement. We concluded that Fourier analysis can be used to represent movement patterns compactly, study their periodicity, stereotypy, and resonance, and assist in computer simulations and models of movement.     

The φ-maze: A versatile automated T-maze for learning and memory experiments in the rat

The φ-maze is a novel implementation of the T-maze that can be used for various behavioral experiments. It consists of a start/goalbox from which a central alley leads to a choice point. Left and right arms return to the start/goalbox, where reinforcers are delivered. A holding chamber at the choice point can be used for delayed (non)matching-to-sample experiments. Lamps mounted under the translucent acrylic floor serve as visual stimuli. The design incorporates reliable and inexpensive automated guillotine doors and a modification of a commercially available pellet dispenser that allows the automated dispensing of Froot Loop reinforcers. The φ-maze has been used successfully in experiments involving spatial and visual alternation, visual discrimination, and delayed matching-to-sample.     

Reduction of the elevator illusion from continued hypergravity exposure and visual error-corrective feedback

Ten subjects served as their own controls in two conditions of continuous, centrifugally produced hypergravity (+2 Gz) and a 1-G control condition. Before and after exposure, open-loop measures were obtained of (1) motor control, (2) visual localization, and (3) hand-eye coordination. During exposure in the visual feedback/hypergravity condition, subjects received terminal visual error-corrective feedback from their target pointing, and in the no-visual feedback/hypergravity condition they pointed open loop. As expected, the motor control measures for both experimental conditions revealed very short lived underreaching (the muscle-loading effect) at the outset of hypergravity and an equally transient negative aftereffect on returning to 1 G. The substantial (approximately 17°) initial elevator illusion experienced in both hypergravity conditions declined over the course of the exposure period, whether or not visual feedback was provided. This effect was tentatively attributed to habituation of the otoliths. Visual feedback produced a smaller additional decrement and a postexposure negative aftereffect, possible evidence for visual recalibration. Surprisingly, the target-pointing error made during hypergravity in the no-visual-feedback condition was substantially less than that predicted by subjects’ elevator illusion. This finding calls into question the neural outflow model as a complete explanation of this illusion.     

Practice-based competencies for accreditation of and training in graduate programs in genetic counseling

In January 1996, the American Board of Genetic Counseling (ABGC) adopted 27 practice-based competencies as a standard for assessing the training of graduate students in genetic counseling. These competencies were identified and refined through a collective, narrative process that took place from January through November 1994, and included directors of graduate programs in genetic counseling, ABGC board members and expert consultants. These competencies now form the basis of the document Requirements for Graduate Programs in Genetic Counseling Seeking Accreditation by the American Board of Genetic Counseling (American Board of Genetic Counseling, 1996). The competencies are organized into four domains and are presented and discussed in this article.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January, 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York).     

A case-based approach to the development of practice-based competencies for accreditation of and training in graduate programs in genetic counseling

The American Board of Genetic Counseling (ABGC) sponsored a consensus development conference with participation from directors of graduate programs in genetic counseling, board members, and expert consultants. Using a collective, narrative, and case-based approach, 27 competencies were identified as embedded in the practice of genetic counseling. These competencies were organized into four domains of skills: Communication; Critical Thinking; Interpersonal, Counseling, and Psychosocial Assessment; and Professional Ethics and Values. The adoption of a competency framework for accreditation has a variety of implications for curriculum design and implementation. We report here the process by which a set of practice-based genetic counseling competencies have been derived; and in an accompanying article, the competencies themselves are provided. We also discuss the application of the competencies to graduate program accreditation as well as some of the implications competency-based standards may have for education and the genetic counseling profession. These guidelines may also serve as a basis for the continuing education of practicing genetic counselors and a performance evaluation tool in the workplace.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York).