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.     

Daily self-management and employee work engagement

The present study adopts a bottom-up approach to work engagement by examining how self-management is related to employees' work engagement on a daily basis. Specifically, we hypothesized that on days that employees use more self-management strategies, they report higher resources at work and in turn, are more vigorous, dedicated, and absorbed in their work (i.e., engaged) on these days. We tested this hypothesis in a sample of 72 maternity nurses who filled out an online diary for 5 days (N = 360 data points). In line with our hypotheses, results of multilevel structural equation modeling analyses showed that daily self-management was positively related to the resourcefulness of the daily work environment (i.e., more skill variety, feedback, and developmental opportunities) and consequently, to employees' daily work engagement. However, contrary to our expectations, the measurement model showed that two of the five included self-management strategies (i.e., self-reward and self-punishment) loaded onto a separate factor and were unrelated to all job resources. The findings contribute to our understanding of employees' role in regulating their own daily work engagement.     

Television Situation Comedies: Male Weight,Negative References,and Audience Reactions

In a content analysis of 27 different prime-time television situation comedies, we examined the body weights of 75 central male characters (97% White, 3% Black), the negative references these male characters received about their body shape/weight from female characters, the negative references male characters made about themselves, and the audience reactions (e.g., laughter) to the negative references. It was found that (a) above-average weight males were underrepresented in the programs compared to the general population; (b) the heavier the male character, the more negative references he made about his own body shape/weight; and (c) his negative comments about himself were significantly associated with audience reactions. No relationship was found between the body weight of male characters and negative references from female characters. These findings are contrasted with previous research that examined these variables associated with female characters.