Model Evaluation and Multiple Strategies in Cognitive Diagnosis: An Analysis of Fraction Subtraction Data

This paper studies three models for cognitive diagnosis, each illustrated with an application to fraction subtraction data. The objective of each of these models is to classify examinees according to their mastery of skills assumed to be required for fraction subtraction. We consider the DINA model, the NIDA model, and a new model that extends the DINA model to allow for multiple strategies of problem solving. For each of these models the joint distribution of the indicators of skill mastery is modeled using a single continuous higher-order latent trait, to explain the dependence in the mastery of distinct skills. This approach stems from viewing the skills as the specific states of knowledge required for exam performance, and viewing these skills as arising from a broadly defined latent trait resembling the θ of item response models. We discuss several techniques for comparing models and assessing goodness of fit. We then implement these methods using the fraction subtraction data with the aim of selecting the best of the three models for this application. We employ Markov chain Monte Carlo algorithms to fit the models, and we present simulation results to examine the performance of these algorithms. The work reported here was performed under the auspices of the External Diagnostic Research Team funded by Educational Testing Service. Views expressed in this paper does not necessarily represent the views of Educational Testing Service.     

AIDS, FRAIDS, and Quarantine: Student Responses to Pro-Quarantine Initiatives in California

In the literature on AIDS, only a few empirical social reactivist studies of heterosexuals have been done, probably due to the preoccupation with explaining the incidence of AIDS among high-risk groups. The following study of 563 students enrolled in a large Southern California university adds to the heterosexual student literature by operationalizing an important research variable, FRAIDS, and by embarking on explanatory analysis of attitude and self-reported behavior. FRAIDS, which we will define as the fear of getting AIDS from casual contact sources, may be helpful in explaining both high-risk sexual behavior among heterosexuals and pro-quarantine sentiment. However, only the subsets of the FRAIDS variable (FRAIDS-dry and FRAIDS-wet) proved explanatory. FRAIDS-dry (fear of HIV infection from dry sources) proved significant in explaining sexual activity, while FRAIDS-wet (fear of HIV infection from wet casual contact sources) was found significant in explaining pro-quarantine sentiment. The converse was not true. Using homophobia as a control variable, homophobia was found to overshadow FRAIDS-wet for males but FRAIDS-wet rivaled homophobia in predicting pro-quarantine sentiment for females. Growing quarantine sentiment was noted among the students, as the survey took place during two different time periods (Fall of 1986 ( N = 375) and Spring of 1988 ( N = 188)), essentially before and after the actual vote in November 1986 on a pro-quarantine initiative (Proposition 64) that appeared on the California ballot. This apparent increase in pro-quarantine sentiment among students (and voters) highlights the need for attention to homophobia as well as detailed discussion of the fear of wet casual contact in AIDS education.     

Sense mode and coupling in a vigilance task

Usarmymedical Research Laboratory, Fort Knox, Kentucky This investigation examined the performance of 36 Ss on three 90-min vigilance tasks. As time on task increased, there was a significant decrease in number of detections and false responses and a corresponding significant increase in response latency. The consistent rank order relationship between stimulus conditions suggests that there were uniform trends among these conventional response measures. There was a significant decline in sensitivity (d′) lor the closely coupled tasks, regardless of the sense mode involved. However, d′ remained fairly stable for the loosely coupled visual task. The significant increase in criterion values(β) suggest that Ss adopt a more conservative mode of responding with increasing time on task. Further, these data indicate that a lack of control of coupling effects, rather than sense mode specificity, may have confounded the interpretation of prior research on visualand auditory tasks.     

Real-life outgroup exposure,self-reported outgroup contact and the other-race effect

People are better at recognizing faces from their own racial or ethnic group compared with faces from other racial or ethnic groups, known as the other-‘race’ effect (ORE). Several theories of the ORE assume that memory for other-race faces is impaired because people have less contact with members of other racial or ethnic groups, resulting in lower visual expertise. The present research investigates contact theories of the ORE, using self-report contact measures and objective measures of potential outgroup exposure (estimated from participants' residential location and from GPS tracking). Across six studies (total N = 2660), we observed that White American and White German participants displayed better memory for White faces compared with Black or Middle Eastern faces, whereas Black American participants displayed similarly equal or better memory for White compared with Black faces. We did not observe any relations between the ORE and objective measures of potential outgroup exposure. Only in Studies 2a and 2b, we observed very small correlations (rs = −.08 to .06) between 4 out of 30 contact measures and the ORE. We discuss methodological limitations and implications for theories of the ORE.     

A recognition advantage for members of higher-status racial groups

The other-race effect (ORE) is a recognition memory advantage afforded to one's racial ingroup versus outgroup. The motivational relevance of the ingroup—because of relationships, belonging and self-esteem—is central to many theoretical explanations for the ORE. However, to date, the motivational relevance of outgroups has received considerably less attention in the ORE literature. Across six experiments, Black, White, Asian and Latinx American participants consistently demonstrated better recognition memory for the faces of relatively higher-status racial/ethnic group members than those of lower-status groups. This higher-status recognition advantage even appeared to override the ORE, such that participants better recognized members of higher-status outgroups—but not an outgroup of equivalent status—compared to members of their own ingroup. However, across a variety of self-reported perceived status measures, status differences between the high- and low-status groups generally did not moderate the documented recognition advantage. These findings provide initial evidence for the potential role of group status in the ORE and in recognition memory more broadly, but future work is needed to rule out alternative explanations.     

Wittgenstein’s Picture Theory and the Distinction between Representing and Depicting

In this paper, I draw attention to the often-overlooked Tractarian distinction between representing (darstellen) and depicting (abbilden), provide a clear account of it and examine how it affects our understanding of the notions of ‘being a picture’, meaningfulness, truth, and falsity in the Tractatus. I also look at the recent debate in the literature on the notion of truth and show that Glock’s claim that the official theory of the Tractatus is to be accounted in terms of obtainment only and deflationary accounts such as Hacker’s derive from a failure to notice the distinction between representing and depicting (in the case of Glock) or a misconception of depicting (in the case of Hacker). Finally, I argue against the idea that either representing or depicting should be dispensed with. Both are necessary for Wittgenstein to account for every case of a proposition being a picture of reality.     

Research Report: Antenatal HIV testing from the perspective of pregnant women and health clinic staff in South Africa—implications for pre- and post-test counselling

HIV testing is not routinely available at present in health clinics in Umtata, South Africa. However current statistics indicate that up to 25% of the population may be infected. Such findings imply that HIV testing and counselling should be introduced in health clinics as a means of promoting HIV prevention and reducing the risk of vertical transmission. However this would only be beneficial if staff are prepared to implement it and patients are willing to test. The issues are couched in a background of political activity surrounding HIV that may question approaches to HIV testing and a lack of availability of interventions to prevent mother to infant transmission. Furthermore the infrastructures of counselling training and provision may not be universally available, especially in pressured rural clinics. Therefore, a group of clinic staff and pregnant women, in rural and urban health centres in Umtata, were asked to participate in focus group discussions to elicit attitudes to HIV testing and counselling. In principal the majority of women, particularly in the rural clinic, were willing to have an HIV test, and strongly articulated the desire to test with their partners. Women who were reluctant to test emphasized their fear of receiving the result. The rural women appeared to be far more willing to disclose their HIV status to clinic staff, than urban women. Nevertheless, the discussions illustrated the impact of the stigma surrounding HIV, with clinic staff reporting cases where patients who were suspected to be positive were avoided by health workers. However staff in both clinics were willing to make the effort to implement HIV tests if they were to be made available. Despite the non-availability of rapid testing and interventions to reduce mother to child transmission most women saw advantages to HIV test provision. Pessimism and fear were underlying emotions associated with HIV for both staff and women. The implications for pre- and post-test counselling are discussed.     

Teaching Strategies and Adaptations of Teachers in Multiculturally Diverse Classrooms in Seventh-day Adventist K-8 Schools in North America

The purpose of this study was to describe the experiences of Adventist teachers—their training, their use of instructional strategies, and the challenges they encounter when teaching students of different cultures. Banks' multicultural paradigms was the theoretical framework from which a survey was developed and sent to all K-8 Adventist teachers in the United States and Canada. Strategies relating to the self-concept development and ethnic additive paradigms were used most frequently by Adventist teachers while those associated with the language paradigm were used the least. Almost half of the teachers subscribed to the goal that “students are individuals with distinct personalities regardless of their background” while about 10% of the teachers considered the goals relating to “protection of diverse groups” the most important. Their strategy use was not related to their most important goals (Nels) for multicultural education. Forty percent of the teachers had no training in multicultural education and the study recommends training so that Adventist teachers will have more effective strategies for relating to diverse students.     

The role of the insular cortex in taste function

In spite of over 30 years of research, the role of the Insular Cortex (IC) in taste memory still remains elusive. To study the role of the IC in taste memory, we used conditioned taste aversion (CTA) for two different concentrations of saccharin; 0.1% which is highly preferred, and 0.5% which is non-preferred. Rats that had been IC lesioned bilaterally with ibotenic acid (15 mg/ml) before CTA showed significant learning impairments for saccharin 0.1% but not for saccharin 0.5%. To test CTA memory retention, rats lesioned a week after CTA training became completely amnesic for saccharin 0.1% yet only mildly impaired for saccharin 0.5%. Interestingly, the resulting preference for either concentration matched that of IC lesioned animals when exposed to either saccharin solution for the first time, but not those of sham animals, implying that IC lesions after CTA for either saccharin solution rendered complete amnesia, irrespective of the original preference. Our data indicate that an intact IC is essential for CTA learning and retention, as well as for an early neophobic response, but not for taste preference itself. Our data supports a model where the IC is involved in general taste rejection.     

The Generalized DINA Model Framework

The G-DINA (generalized deterministic inputs, noisy “and” gate) model is a generalization of the DINA model with more relaxed assumptions. In its saturated form, the G-DINA model is equivalent to other general models for cognitive diagnosis based on alternative link functions. When appropriate constraints are applied, several commonly used cognitive diagnosis models (CDMs) can be shown to be special cases of the general models. In addition to model formulation, the G-DINA model as a general CDM framework includes a component for item-by-item model estimation based on design and weight matrices, and a component for item-by-item model comparison based on the Wald test. The paper illustrates the estimation and application of the G-DINA model as a framework using real and simulated data. It concludes by discussing several potential implications of and relevant issues concerning the proposed framework.