Separability of item and person parameters in response time models

This paper discusses two forms of separability of item and person parameters in the context of response time (RT) models. The first is separate sufficiency: the existence of sufficient statistics for the item (person) parameters that do not depend on the person (item) parameters. The second is ranking independence: the likelihood of the item (person) ranking with respect to RTs does not depend on the person (item) parameters. For each form a theorem stating sufficient conditions, is proved. The two forms of separability are shown to include several (special cases of) models from psychometric and biometric literature. Ranking independence imposes no restrictions on the general distribution form, but on its parametrization. An estimation procedure based upon ranks and pseudolikelihood theory is discussed, as well as the relation of ranking independence to the concept of double monotonicity.I am indebted to Wim van der Linden for bringing Thissen's (1983) paper to my notice, and to Martijn Berger, Frans Tan, and the anonymous reviewers for their constructive comments on earlier drafts of this paper.     

The numbers game: Gender and attention to numerical information

Research suggests that males outperform females on standardized tests of math ability from early adolescence onward. Several explanations for this difference focus on the different experiences of females and males with numerical information. We reasoned that males have more experience with numerical information than females because typical male interests (e.g., sports) are more likely to involve numerical information than typical female interests (e.g., physical appearance). Thus, we predicted that males would attend more to numerical information than would females, at least when the information was presented in a male-related or gender-neutral context. Females were expected to attend more than males when the context was female-related. Results using White/Caucasian subjects provided some support for these predictions. Implications for future research on the relationship between the gender-linkage of math materials and gender differences in math performance are discussed.     

Conditional Control of Fluid Consumption in an Occasion Setting Paradigm Is Independent of Pavlovian Associations

Drug states, flavors, and contextual cues were each trained as conditional discriminative stimuli to control a saccharin-LiCl association. In transfer tests, drug states transferred control over consumption to other flavored solutions and to food. Contexts and flavors transferred control only to other flavored solutions. Pavlovian control groups given direct pairings of context-LiCl or flavor-LiCl did not show reliable transfer. However, these control groups did show greater or the same aversion to the specific context or flavor predicting LiCl compared to the context or flavor discrimination groups. The dissociation of the discrimination and Pavlovian groups on transfer versus preference tests suggests that performance on the occasion setting task cannot be due to simple excitation or learning about a unique compound cue. Data from extinction procedures provide further support for the dissociation between simple excitation and occasion setting.     

Influence of subject and interviewer characteristics on the reliability of young adults' self-reports of drinking

The influence of subject and interviewer characteristics on the reliability of self-reports of alcohol consumption among young adults was investigated. Data were gathered from black and white college students of both sexes (N's=24) using a time-line procedure. The results snowed that these young adults provided highly reliable self-reports regarding their use of alcohol. Test-retest correlations for a criterion interval of 90 days were .96, .93, and .97 for the numbers of abstinent, moderate-drinking, and heavy-drinking days, respectively. Analyses also showed that white female subjects generally provided more reliable reports of abstinent and heavy-drinking days and that white female interviewers gathered more reliable reports across the three drinking disposition categories. These findings suggest that nonalcoholic young adults' retrospective reports of their drinking behavior can be reliably assessed using the time-line methodology. Future research is required to determine the validity of these self-reports and to understand the differential influence of subject and interviewer characteristics on the levels of reliability found.     

Postdecision evaluation of choice alternatives as a function of valence of alternatives,choice, and expected delay of choice consequences

The effects of valence of alternatives, choice, and expected delay of choice consequences on postdecision evaluations of choice alternatives were studied by either giving subjects a choice between two experimental tasks (both either pleasant or unpleasant) or assigning subjects their initially preferred task. Crosscutting valence and choice, subjects expected either no delay, 10-min delay, or 30-min delay before engaging in the task. All subjects evaluated both tasks immediately after the delay instructions but before experiencing the actual delay. Results confirmed the expected dissonance effect; that is, an upward evaluation of the chosen alternative and a downward evaluation of the rejected alternative, relative to no-choice conditions. Moreover, the relative upward evaluation of the chosen alternative increased as the expected delay decreased. Valence was not found to interact with other variables. The results are discussed in terms of differential salience of choice alternatives.     

Interpersonal Reactions to Depression and Physical Disablllty In Dyadic Interactions1

Examined the interpersonal responses of persons engaged in dyadic interactions with confederates who enacted either depressed or socially appropriate roles and appeared either with or without a physical disability. Subject negative evaluations of confederates were indirectly obtained from a thought-listing measure. The overt behaviors of subjects were surreptitiously recorded on videotape and measures of verbal and nonverbal behavior were acquired. Subjects spoke less to the depressed targets and had significantly higher rates of negative evaluations of these persons. In addition, subjects gazed less at the depressed confederates. These effects were not moderated by target physical appearance. Findings are discussed as they relate to social models of depression and the stigmatizing effects of disability.     

Differentiated additive androgyny model: relations between masculinity, femininity, and multiple dimensions of self-concept.

Masculinity (M) and femininity (F) were related to multiple dimensions of self-concept in 2 large studies. Androgyny theory predicts that M and F contribute positively to self-concept, but the effect of F has been nil in research using global self measures. Here, consistent with the new differentiated additive model, the relative contribution of M and F varied substantially, depending on the area of self-concept; F contributed more positively to self-concept facets that were more stereotypically feminine. Support for the model was consistent across self-responses and responses by significant others (Study 1) and across 5 age groups in early-to-middle adolescence (Study 2).     

The Waffle Phenomenon: Negative Evaluations of Those Who Shift Attitudinally1

The past two presidential campaigns have been filed with charges that the Democratic nominee “changed his mind” on various issues. The present research explored the possibility that negative evaluations may be produced by attitude change per se. In the first experiment, subjects responded to a stranger whose attitudes remained stable or who changed his attitudes over a period of two months vs. one year. Individuals who changed their attitudes were generally evaluated more negatively than those whose attitudes remained stable; the amount of time over which the change occurred produced no effect. A second expcriment sought to determine if the direction of change (toward increased or decreased similarity with subjects) influenced evaluations of a stranger. Attitude change which resulted in decreased similarity was rated most negatively. Even when a stranger changed his attitudes in the direction of greater similarity with subjects, however, he was still regarded as less decisive, less reliable, and a worse leader than was an individual with stable attitudes. This negative evaluation of attitude change was labeled the “waffle phenomenon”, and the implications for political candidates were discussed.     

Anorexia and conditioned taste aversions in the rat

The present study examined whether or not certain anorexic agents produced flavor aversions. Rats showed comparable anorexia when injected with lithium chloride, ammonium sulfate, arginine·HCl, and d-glucose. Only lithium chloride produced a flavor aversion to either a novel liquid or food. Only arginine was found to interfere with the formation or recall of an association. The effects of the other chemicals were discussed in terms of the relationship between anorexia and induced sickness.