On the existence and uniqueness of maximum-likelihood estimates in the Rasch model

Necessary and sufficient conditions for the existence and uniqueness of a solution of the so-called unconditional (UML) and the conditional (CML) maximum-likelihood estimation equations in the dichotomous Rasch model are given. The basic critical condition is essentially the same for UML and CML estimation. For complete data matricesA, it is formulated both as a structural property ofA and in terms of the sufficient marginal sums. In case of incomplete data, the condition is equivalent to complete connectedness of a certain directed graph. It is shown how to apply the results in practical uses of the Rasch model.Paper read at the European Meeting of the Psychometric Society, Groningen, June 19–21, 1980.Part of the research reported herein was done while the author was staying at the Pulmologisches Zentrum der Stadt Wien; he is indebted to Professor Dr. F. Muhar and Dr. R. Mutschlechner for providing excellent working conditions.     

Leader Inquisitiveness,Political Skill,and Follower Attributions of Leader Charisma and Effectiveness: Test of a moderated mediation model

Given the variability in personality's relationship with leadership and the use of personality measures in leader selection and assessment, we examine the joint influence of leader trait inquisitiveness and leader political skill on subordinate perceptions of leader charisma and effectiveness. Findings indicate a positive main effect of political skill on charisma, the positive relationship between inquisitiveness and charisma is moderated by heightened political skill, and charisma mediates the relationship between the inquisitiveness by political skill interaction and perceived effectiveness. The moderated mediation results of our study suggest that organizations should not only select creative and imaginative leaders, but also select those who are politically skilled or provide political skill training.     

Music fan personality stereotyping in a sample of South African young adults

This study aimed to elicit stereotypes about personality characteristics of young adults residing in South Africa, based solely on music genres. Participants were 941 undergraduate students at a South African university. They responded to a number of surveys about music genre preferences and personality traits. Data were analysed for trends and patterns in personality attributions based on music genre preferences. The results indicated that participants hold distinct stereotypes about the personality traits, so that those with who preferred Classical, Blues and Jazz music were seen to display higher openness to experience than comparison groups with other music genre preferences. Those with Rap, Reggae and Folk music genre preferences were stereotyped as artistic and unconventional. Young South African adults appear to use musical preference to define personality.     

A loss function for alpha factor analysis

Most of the factor solutions can be got by minimizing a corresponding loss function. However, up to now, a loss function for the alpha factor analysis (AFA) has not been known. The present paper establishes such a loss function for the AFA. Some analogies to the maximum likelihood factor analysis are discussed.The author is greatly indebted to Prof. Henry F. Kaiser (University of California, Berkeley) for his kind encouragement. He is also indebted to an anonymous referee ofPsychometrika for having confronted him with the problem in 1977. Financial support by the Wiener Hochschuljubiläumsstiftung is gratefully acknowledged.     

Paradoxical consequences of Balzer''s and G?hde''s criteria of theoreticity. Results of an application to ten scientific theories

It is shown that the criteria of T-theoreticity proposed by Balzer and Gähde lead to strongly counterintuitive and in this sense paradoxical results: most of the obviously empirical or at least nontheoretical terms come out as theoretical. This is demonstrated for a lot of theories in different areas. On the way, some improved and some new structuralist theory-reconstructions are given. The conclusion is drawn that the T-theoreticity of a term cannot possibly be proved on the basis of the mathematical structure of theory T alone (as Gähde and Balzer suggest). Rather, an independent notion of pre-T-theoreticity and-more importantly-of empiricity is needed; i.e., not empirical and not pre-T-theoretical are independent, necessary but not sufficient conditions for T-theoretical (this is also a necessary complement of Sneed's original criterion). Finally it is asked whether the structuralist criterion of T-theoreticity complemented by such independent conditions would be a satisfactory answer to Putnam's challenge, and the answer again is negative: the criterion is not able to distinguish between empirically contentful and completely contentless (superfluous) theoretical terms.     

Perceptions of rape victims and assailants: Effects of physical attractiveness,acquaintance, and subject gender

Subjects read different versions of a rape case in which the victim was walking alone at night and the defendant was obviously guilty. Female subjects saw the crime as more debilitating for the victim and were more punitive than male subjects. Female subjects considered the victim less responsible when the defendant was unattractive than when the defendant was attractive. Presence or absence of prior casual acquaintance between the victim and assailant interacted with other factors. With prior acquaintance, male subjects considered the victim more responsible than female subjects, unattractive victims were considered more responsible than attractive victims, and unattractive defendants were considered more likely to engage in future antisocial behavior than attractive defendants. Although biased by other factors, level of victim blame was low overall. Yet subjects seemed reluctant to believe the rapist and his victim were unacquainted and seemed to consider the rape as sexually, rather than aggressively, motivated.The authors gratefully acknowledge the helpful comments of Andrea R. Halpern and T. Joel Wade. Portions of this paper were presented at the meetings of the Eastern Psychological Association, Buffalo, New York, April 1988.     

Eine neue Wahrnehmungstäuschung

Zusammenfassung Die Grenze des durch beide Arme bestimmten menschlichen Doppelgreifraumes hat die Gestalt einer Kugeldoppelhaube. Alle Punkte dieser Grenzfläche sind durch Greifbewegung gleich bequem (noch) erreichbar, wobei der Doppelarm als einheitliches Greif organ aufzufassen ist. Es besteht für diese Fläche nach allen Richtungen Gleichheit der Greifentfernung. Durch Spiegel-Hand-Versuche kann man nunmehr zeigen, daß alle Punkte dieser Grenzfläche bei visueller Wahrnehmung auch vom Auge aus gleichweit entfernt erscheinen, obwohl dies geometrisch schon wegen der exzentrischen Lage des Auges keineswegs der Fall ist. Die Grenze des Doppelgreifraumes nimmt beim Aufbau des menschlichen Sehraumes eine Schlüsselstellung ein.Man kann an dem beschriebenen Phänomen mit Aussicht auf Erfolg neue psychische Grundgesetze aufspüren. Versuche mit sogenannten Contergankindern können hierzu neue Aufschlüsse liefern.

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Summary The periphery delimiting the space circumscribed by the motional range of both human arms takes the shape of a double truncated sphere. All points of this periphery may still be reached with equal ease by a mere gripping motion (regarding, for the purposes of this study, the two arms as a single prehensile organ), and peripheral equidistance of reach exists in all directions. By means of tests in which the outstretched hand is expediently reflected in a mirror it can now be demonstrated that in visual perception (due to the above-mentioned motional equidistance) the entire double-spherical periphery appears equidistant also from the vantage-point of the eye, even though geometrically this is by no means the case. The periphery of the bilateral space of prehension, therefore, assumes a key position in the configuration of space as perceived by the human eye.The phenomenon opens views fowards new basic psychic laws. Also experiments with thalidomide children may provide new insights.