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This study investigated some of the serial patterns among interresponse times during Sidman avoidance. It was found that the momentary probability of a response was determined by the length of exposure to the avoidance procedure during a session, by the time since the last shock, and by the duration of the preceding IRT.
Habituation, satiation, adaptation, and boredom are a few of the words used to label the behavioral consequences of a fundamental operation: repeated and protracted presentation of a stimulus. The cumulative measure of the response associated with that stimulus is expected to display an inflection at some time Ti after which the slope approaches zero. Ti can be estimated by dividing the square of the interresponse time (IRT)2 by the duration of the response associated with reinforcement (Rt), where Rt is expressed in the nearest whole temporal unit of interresponse time. Calculated TiS for habituation to the same sexual, aggressive, or social stimuli are compatible with general observation.
Member of the ZIP(ZRT and IRT-like protein) gene family belongs to metal transporter super family, they were firstly identified in plants, and then were found at all phylogenetic levels. They are capable of transporting a variety of cations, including cadmium, iron, zinc and manganese. These founding are very important for us to understand the metal deficiency or over accumulation at molecular level. The structure and functions of the novel metal transporter family, ZIP family, found in Arabidopsis recent years will be reviewed in this paper.
A new class of parametric IRT models for dichotomously scored items is presented. The new class of models is a subclass of both the class of models defined by the four-parameter logistic item response function and the nonparametric Double Monotonicity (DM) model. Three special cases of this new class of models are discussed. One of these special cases is shown to be the one-parameter logistic Rasch model. Both specific objectivity at the interval level of measurement and the sufficiency of the total score for the latent trait are shown to be measurement properties of the whole new class of models. For maximum likelihood estimation of the model parameters, both a joint and a conditional likelihood function are proposed.
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Item response theory methods were used to study differential item functioning (DIF) between gender groups on a measure of stress reaction. Results revealed that women were more likely to endorse items describing emotional vulnerability and sensitivity, whereas men were more likely to endorse items describing tension, irritability, and being easily upset. Item factor analysis yielded 5 correlated factors, and the DIF analysis, in turn, revealed differential gender mean differences on these factors. This finding illustrates how even in an essentially unidimensional scale, comparison of group mean differences can be affected by multidimensionality caused by item clusters that share similar content. Results do not support arguments that measures of negative affective dispositions "artificially" produce gender mean differences by focusing on specific selected content areas.
This article describes a general item response theory-based factor analytic procedure that allows assessment of the equivalence between 2 administrative modes of a questionnaire: paper and pencil, and Internet based. The theoretical relations between the present procedure and other methods used in previous empirical research are shown, and the advantages of the procedure are discussed. An empirical application based on 2 personality questionnaires is given, and the results are compared with the results of using traditional procedures for assessing equivalence. The substantive implications of the results, as well as suggestions for further research and methodology, are discussed.
The authors compared the fit of the 2- and 3-parameter logistic models (2PLM; 3PLM) on 15 unidimensional factor scales derived from the Minnesota Multiphasic Personality Inventory--Adolescent item pool. Log-likelihood chi-square deviance tests indicated that a 3PLM provided an improved fit. However, residual statistics indicated that the difference in fit between the 2 models was negligible. An unexpected finding was that from 10% to 30% of the items had substantial lower asymptote parameters (c > or = .10) when the scales were scored in the pathology or nonpathology directions. The authors argue that the large lower asymptote parameters are attributable to item-content ambiguity possibly caused by item-level multidimensionality. These findings suggest that the direction of scoring can critically affect an item response theory analysis.
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The appropriateness of the Binomial Trials Model for test data that consist of multiple attempts of the same item needs to be determined because the presence of learning or fatigue effects may violate the model's assumption of local independence. The purpose of this study was to determine what effect the severity of the violation of local independence (VLI), coupled with different sample size (SS), test length (TL), and test difficulty (TD) had on the estimation of the model difficulty parameter, b, using computer simulation techniques. Each of the following conditions was replicated 100 times under a completely crossed design: SS (100, 200, 500, 2,000); TL (5, 10, 20, 25 attempts); TD (-1.2, 0.0, 1.2); and VLI (from no violation to complete violation). Examinee ability or latent trait was pseudorandomly drawn from a standard normal distribution, and the b-parameter was estimated using a maximum likelihood procedure on generated test scores. Regardless of SS, TL, and TD, the b-parameter tended to be overestimated for situations in which the VLI condition simulated fatigue and underestimated when the VLI condition simulated late-test learning or practice effect. The findings suggest that violations of local independence, at least as simulated in this study, could seriously bias the difficulty parameter estimates if all examinees tested exhibited the dependency.
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A structural multilevel model is presented where some of the variables cannot be observed directly but are measured using tests or questionnaires. Observed dichotomous or ordinal polytomous response data serve to measure the latent variables using an item response theory model. The latent variables can be defined at any level of the multilevel model. A Bayesian procedure Markov chain Monte Carlo (MCMC), to estimate all parameters simultaneously is presented. It is shown that certain model checks and model comparisons can be done using the MCMC output. The techniques are illustrated using a simulation study and an application involving students' achievements on a mathematics test and test results regarding management characteristics of teachers and principles.
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Sequential dependencies were investigated with two rats in a mixed and in a tandem differential-reinforcement-of-low-rate-responding schedule. In each schedule, 5-sec and 15-sec components were presented in fixed alternation. In the mixed schedule, a 5-sec interresponse time followed a 15-sec interresponse time and a 15-sec interresponse time followed a 5-sec interresponse time in predictable sequence. The correlation between prior and subsequent interresponse times, however, existed only when the prior interresponse time resulted in reinforcement. In the tandem schedule, an interresponse time greater than 5 sec in the differential-reinforcement-of-low-rate 5-sec component was not associated directly with reinforcement. One subject demonstrated sequential response patterns similar to those noted in the mixed schedule, even though the prior 5-sec interresponse time was not reinforced in the tandem schedule. The results indicate that the prior interresponse time length alone is not sufficient to influence the subsequent interresponse time length. Implications are, however, that a temporal response pattern arises when an interresponse interacts with schedule contingencies to control the interreinforcement interval.