Disruption of a temporal discrimination under response-independent shock

The responding of rats was reinforced on one key after a 1-sec auditory stimulus and on a second key after a 5-sec stimulus. With errors punished by a short timeout, all subjects achieved a high level of accuracy. A chain of responses during the stimuli mediated the performance so that when the auditory signals were omitted accuracy decreased only slightly. Response-independent aversive stimulation superimposed upon this procedure both suppressed the total amount of behavior and reduced the accuracy of the discriminative performance, the intensity of the stimulus determining the error rate. The increase in errors under these conditions may have depended in part upon differential suppression of members of the response chain, but such suppression was not necessary, since error rate increased even in its absence. Furthermore, the locus of response disruption within the chain was not consistent from day to day either for any individual animal or across animals.     

Spline smoothing with model-based penalties

Nonparametric regression techniques, which estimate functions directly from noisy data rather than relying on specific parametric models, now play a central role in statistical analysis. We can improve the efficiency and other aspects of a nonparametric curve estimate by using prior knowledge about general features of the curve in the smoothing process. Spline smoothing is extended in this paper to express this prior knowledge in the form of a linear differential operator that annihilates a specified parametric model for the data. Roughness in the fitted function is defined in terms of the integrated square of this operator applied to the fitted function. A fastO(n) algorithm is outlined for this smart smoothing process. Illustrations are provided of where this technique proves useful.     

Maximum marginal likelihood estimation for semiparametric item analysis

The item characteristic curve (ICC), defining the relation between ability and the probability of choosing a particular option for a test item, can be estimated by using polynomial regression splines. These provide a more flexible family of functions than is given by the three-parameter logistic family. The estimation of spline ICCs is described by maximizing the marginal likelihood formed by integrating ability over a beta prior distribution. Some simulation results compare this approach with the joint estimation of ability and item parameters.IRCAMThe research reported in this paper was supported by Grants APA320 and A4035 from the Natural Sciences and Engineering Research Council of Canada. It was also supported by Contract No. F41689-82-C-10020 from the Air Force Human Resources Laboratory to Educational Testing Service. The author wishes to thank M. Abrahamowicz for his assistance and R. Darrell Bock for providing the parameters for the items used in the simulations.     

Does Smoking by Pregnant Women Influence IQ, Birth Weight, and Developmental Disabilities in Their Infants? A Methodological Review and Multivariate Analysis

Neuropsychologists are asked frequently to address the issue of the cause of a variety of central nervous system problems that may affect higher cortical function. One such issue is the relationship of maternal smoking to adverse reproductive outcomes involving neocortical insult including mental retardation, learning disabilities, attention-deficit hyperactivity disorder, and other insults that may be related to prolonged hypoxic states in utero. The instant paper develops the issue of causation as a scientific inquiry, reviews several traditional, applicable models, and critiques these models. An additional model of motility is proposed and discussed. The issue of the relationship of maternal smoking to adverse reproductive outcomes is then addressed from a review perspective along with new empirical analyses, the latter demonstrating that researchers tend to draw causal conclusions independent of whether the respective design of their studies would support conclusions about the causation of an event. Causal conclusions in the absence of causal designs have often lead to incomplete and incorrect conclusions. It is necessary to match conclusions not only to the outcomes of a research project but also to its design and accompanying limitations.     

Changes in Primary Process Thinking of a Prepsychotic Adolescent in Psychotherapy

The main goal of this study was to measure longitudinally change in thought processes and reality testing of a prepsychotic adolescent undergoing psychotherapy. The Holt scoring system for measuring primary process from Rorschach responses was the main measuring instrument. Four Rorschachs were administered over a period of three years. The results of the latter were compared with the clinical ratings of two psychiatrists. While clinical change in response to treatment was slight, there did appear to be a shift from primary to more secondary forms of formal thought processes as determined by the Rorschach.     

Alberta's suicide prevention training programs: a retrospective comparison with Rothman's developmental research model

Developmental research is used to transform existing knowledge into applied programs. A social research and development (R&D) method, developed by Rothman for the human service professions, is compared with the method used to develop the Suicide Prevention Training Programs in Alberta, Canada. A retrospective review compares the development of these programs, which have since been implemented both nationally and internationally, with Rothman's model; discusses social R&D as a transformation methodology; and draws conclusions about the probable success of using developmental research methods in the human services. The review finds that the Alberta method closely paralleled the phases of Rothman's model. Results show that the transformation of knowledge about suicide into widely disseminated suicide prevention training programs can be attributed to the application of social R&D principles. The study concludes that the use of developmental research methods to establish human service programs should increase the probability of their success.