大学生网名命名动机的研究

本研究自编的“大学生网名命名动机量表”有较高的信度和效度。大学生的网名命名的动机按重要程度依次为:张扬个性、便捷自然、寻求自我价值感、祟尚流行和宣泄情感。网名命名动机在性别间存在显著差异,女生命名网名时,认为“张扬个性”与“便捷自然”较重要,而男生认为“寻求自我价值感”、“宣泄情感”与“崇尚流行”更重要。年级因素在命名动机上存在显著差异。低年级学生认为网名应当“张扬个性”、“寻求自我价值感”和“宣泄情感”,而高年级认为网名应“崇尚流行”和“便捷自然”。文理科学生仅在“便捷自然”动机上有差异。     

How to find what's in a name: Scrutinizing the optimality of five scoring algorithms for the name‐letter task

Although the name‐letter task (NLT) has become an increasingly popular technique to measure implicit self‐esteem (ISE), researchers have relied on different algorithms to compute NLT scores and the psychometric properties of these differently computed scores have never been thoroughly investigated. Based on 18 independent samples, including 2690 participants, the current research examined the optimality of five scoring algorithms based on the following criteria: reliability; variability in reliability estimates across samples; types of systematic error variance controlled for; systematic production of outliers and shape of the distribution of scores. Overall, an ipsatized version of the original algorithm exhibited the most optimal psychometric properties, which is recommended for future research using the NLT. Copyright © 2009 John Wiley & Sons, Ltd.     

Estimation of the Nonlinear Random Coefficient Model when Some Random Effects Are Separable

A method is presented for marginal maximum likelihood estimation of the nonlinear random coefficient model when the response function has some linear parameters. This is done by writing the marginal distribution of the repeated measures as a conditional distribution of the response given the nonlinear random effects. The resulting distribution then requires an integral equation that is of dimension equal to the number of nonlinear terms. For nonlinear functions that have linear coefficients, the improvement in computational speed and accuracy using the new algorithm can be dramatic. An illustration of the method with repeated measures data from a learning experiment is presented.     

Effects of cocaine and alcohol, alone and in combination, on human learning and performance.

The acute effects of cocaine hydrochloride (4 to 96 mg/70 kg) and alcohol (0 to 1.0 g/kg), administered alone and in combination, were assessed in two experiments with human volunteers responding under a multiple schedule of repeated acquisition and performance of response chains. Subjects were intermittent users of cocaine and regular drinkers who were not cocaine or alcohol dependent. Alcohol was mixed with orange juice and ingested in six drinks within 30 min; cocaine was administered intranasally 45 min after completion of drinking. In each component of the multiple schedule, subjects completed response sequences using three keys of a numeric keypad. In the acquisition component, a new sequence was learned each session. In the performance component, the response sequence always remained the same. Results were consistent in both experiments, despite variations in the order in which the drugs were tested alone and in combination. Alcohol administered alone increased overall percentage of errors and decreased rates of responding in the acquisition component, whereas responding in the performance component generally was unaffected. Cocaine administered alone decreased rates of responding but did not affect accuracy of responding in the acquisition component, and enhanced accuracy of responding without affecting rates of responding in the performance component. The combined doses of cocaine and alcohol attenuated the effects observed with alcohol and cocaine alone. These results suggest that, under the conditions investigated in this study, (a) alcohol produces greater behavioral disruption than cocaine or cocaine-alcohol combinations, (b) cocaine and alcohol each attenuate effects of the other, and (c) such attenuation is most pronounced for cocaine attenuating the disruptive effects of alcohol.     

Effects of ethanol on reinforced variations and repetitions by rats under a multiple schedule.

Response sequences emitted by five Long-Evans rats were reinforced under a two-component multiple schedule. In the REPEAT component, food pellets were contingent upon completion of a left-left-right-right (LLRR) sequence on two levers. In the VARY component, pellets were contingent upon variable sequences (i.e., a sequence was reinforced only if it differed from each of the previous five sequences). The rats learned to emit LLRR sequences in the REPEAT component and variable sequences in VARY. Intraperitoneal injections of ethanol (1.25, 1.75, and 2.25 g/kg) significantly increased sequence variability in REPEAT, thereby lowering reinforcement probability, but had little effect on sequence variability in the VARY component. These results extend previous findings that alcohol impairs the performance of reinforced repetitions but not of reinforced variations in response sequences.     

Effects of scopolamine on repeated acquisition of radial-arm maze performance by rats.

Rats repeatedly acquired the performance of selecting only the four baited arms in an automated eight-arm radial maze, with the arms containing food pellets randomly assigned prior to each session. During each 14-trial (trial: obtain all four pellets) daily session, the number of errors (selecting nonbaited arms or repeating arm selections) showed a within-session decline, and choice accuracy for the first four arm selections showed a positive acceleration across trials for all rats. An index-of-curvature statistic, calculated for total errors, was used to quantify both the within- and between-session improvement of performance. Scopolamine (0.03 to 0.3 mg/kg, ip), but not methylscopolamine (0.3 mg/kg), reduced the accuracy of the first four selections of each trial and increased total within-session errors for all rats. Session times also were increased by scopolamine. An examination of within-session accuracy showed only slight signs of improvement at the higher dosages of scopolamine. The results indicate that behavior in transition states maintained by reinforcement contingencies in the radial maze is similar to that maintained by extended chained schedules, despite the fact that some of the stimuli controlling behavior in the maze are absent at the moment behavior is emitted.     

Trend in correlated proportions

A random effects probit model is developed for the case in which the same units are sampled repeatedly at each level of an independent variable. Because the observed proportions may be correlated under these conditions, estimating their trend with respect to the independent variable is no longer a standard problem for probit, logit or loglinear analysis. Using a qualitative analogue of a random regressions model, we employ instead marginal maximum likelihood to estimate the average latent trend line. Likelihood ratio tests of the hypothesis of no trend in the average line, and the hypothesis of no differences in average trend lines between experimental treatments, are proposed. We illustrate the model both with simulated data and with observed data from a clinical experiment in which psychiatric patients on two drug therapies are rated on five occasions for the presence or absence of symptoms.Supported by a grant from the MacArthur Foundation and National Science Foundation Grant BNS85-11774.The authors are indebted to James Heckman for calling our attention to the Clark algorithm.     

Effects of d-amphetamine, cocaine, and phencyclidine on the acquisition of response sequences with and without stimulus fading.

In each of three components of a multiple schedule, monkeys were required to emit a different sequence of four responses in a predetermined order on four levers. Sequence completions produced food on a fixed-ratio schedule. Errors produced a brief timeout. One component of the multiple schedule was a repeated-acquisition task where the four-response sequence changed each session (learning). The second component of the multiple schedule was also a repeated-acquisition task, but acquisition was supported through the use of a stimulus-fading procedure (faded learning). In a third component of the multiple schedule, the sequence of responses remained the same from session to session (performance). At higher doses, d-amphetamine, cocaine, and phencyclidine decreased the overall rate of responding and increased the percent errors in all three components. At lower doses, however, the three drugs produced selective effects on errors. Errors were increased in the learning component at lower doses than those required to disrupt the behavior in the faded-learning component. The performance component tended to be the least sensitive to disruptive drug effects. The data are consistent with the view that stimulus fading can modulate the effects of drugs on acquisition.     

Neuropsychological changes in children with cancer: The treatment of missing data in longitudinal studies

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.