Characterizing the manifest probabilities of latent trait models

The problem of characterizing the manifest probabilities of a latent trait model is considered. The item characteristic curve is transformed to the item passing-odds curve and a corresponding transformation is made on the distribution of ability. This results in a useful expression for the manifest probabilities of any latent trait model. The result is then applied to give a characterization of the Rasch model as a log-linear model for a 2 ^J -contingency table. Partial results are also obtained for other models. The question of the identifiability of “guessing” parameters is also discussed. The research reported here is collaborative in every respect and the order of authorship is alphabetical. Dr. Cressie was a Visiting Research Scientist at ETS during the Fall of 1980. His current address is: School of Mathematical Sciences, The Flinders University of South Australia, Bedford Park SA, 5042, AUSTRALIA. The preparation of this paper was supported, in part, by the Program Statistics Research Project in the Research Statistics Group at ETS.     

The logic of arithmetic

Conclusion The arithmetic developed along the lines indicated by Cantor has up until now found no application in the real, as opposed to the mathematical, world. It is to be hoped that the changes suggested in this paper bring mathematics closer to human thought and allow it to be of increasing benefit in its service to mankind.     

The effect of social comparison information on learned helpless and mastery-oriented children in achievement settings

The present study investigates the effect of social comparison information on learned helpless and mastery-oriented children's attributions, behaviour, and affect following a failure experience. Ninety-one fifth grade children experienced failure in the context of high consensus or group failure feedback, low consensus or personal failure feedback or no social comparison feedback. The Jindings point to the robustness of the helpless and mastery response patterns: the behaviour of learned helpless children, as compared to mastery-oriented children, deteriorated following failure regardless of the social comparison feedback they recieved. However, the attributions made by the two groups of children differed. Mastery-oriented children appeared to use social comparison information more accurately in that they appropriately made higher task difficulty ratings when receiving group failure feedback than when receiving personal failure feedback. Learned helpless children were more likely to use a self-derogatory bias and made attributions to their low ability, even when presented with social comparison feedback that was contrary to their bias. These findings are discussed in terms of their implications for education and for intervention with learned helpless childrens.     

Effects of sexual versus fear arousal on alcohol consumption in college males

To compare the effects of pleasant and aversive arousal on alcohol consumption, 18 male undergraduates had three weekly sessions to separately view erotic, mutilation or neutral slides in a simulated memory experiment. Following exposure to the slides, they received access to alcoholic and nonalcoholic beverages, which were presented to half the subjects in a taste rating task, and to half as the result of engaging in an operant lever-press task. Subjects believed these tasks to be distractors during a purported retention interval. Self-report instruments and basal skin conductance confirmed the success of the affective manipulations. However, only the subjects using the taste task after viewing erotic slides significantly increased alcohol consumption. These results question a tension reduction model of drinking and qualify the contribution of autonomic arousal to motivation for drinking.     

Feature distribution and background knowledge in category learning

Three experiments examined the interactions of category structure and prior knowledge in category learning.Experiment 1 examined the distribution of atypical or 'crossover' features in category learning. In real categories, crossover features may be unevenly distributed found primarily in very unusual examples of a category (like whales or ostriches). In contrast, in many psychology experiments, each item has exactly one crossover feature. Even versus uneven distribution of crossover features did not affect category learning when the features were neutral. However, when the features were connected by prior knowledge, it was much harder for subjects to learn the structure with the uneven distribution of crossover features. Experiments 2 and 3 found similar results with a slightly less uneven condition. We conclude that learning is a function of the interaction of category structure and prior knowledge rather than either one alone. Furthermore, knowledge benefits learning even when the category contains contradictions of the knowledge, so long as the contradictions are not very salient.     

Variation in the speech signal as a window into the cognitive architecture of language production

The pronunciation of words is highly variable. This variation provides crucial information about the cognitive architecture of the language production system. This review summarizes key empirical findings about variation phenomena, integrating corpus, acoustic, articulatory, and chronometric data from phonetic and psycholinguistic studies. It examines how these data constrain our current understanding of word production processes and highlights major challenges and open issues that should be addressed in future research.     

Perceptions of Registered Nurses/Midwives and Obstetricians on Having Males as Expectant Fathers Present in the Delivery Room at Public Hospitals in Trinidad and Tobago: Implications for Women and Their Partners

This study explored the perspectives of obstetricians and registered nurses/midwives on the presence of expectant fathers in the delivery room with a view to understanding the implications for the mother as well as the expectant father. A qualitative research design using a phenomenological approach to understand the nuances and challenges that affect the perceptions and attitudes of obstetricians and registered nurses/midwives on the research issue. Five focus group discussions and five key informant interviews were the data collection strategies. Data were coded openly then combined to form themes which were utilized as the framework for data analysis. Three major themes emerged in the findings which included potential benefits to the mother, potential benefits to the father and potential benefits to the relationship. Generally, obstetricians and registered nurses/midwives held positive views about their presence in the delivery suite. This was related to the perceived positive impact that he could have on the woman during the inter-natal and post-natal periods as well as the quality of the relationship. By extension, their presence could have positive long term benefits on the quality of the relationship. The presence of expectant fathers in the delivery room could have a positive impact on the delivery experience for mothers, fathers and the long term relationship. The findings could provide a framework for other studies including a prospective study on the long term implications for the presence of expectant fathers in the delivery room.