Exactly how manyp values is a picture worth? A commentary on Loftus’s plot-plus-error-bar approach

Loftus (1993b) has recently argued that hypothesis testing is largely irrelevant and should be replaced with a “plot-plus-error-bar” (PPE) presentation of the data. We agree that such figures can be useful. However, they do not preclude standard hypothesis testing procedures, and they should be used to supplement rather than to supplant the latter. The insufficiency of PPEs is most apparent in the case of mixed designs and factorial within-subject designs. In such cases, there is no single value that is appropriate to represent the standard error.     

Behavioural goals determine inhibitory mechanisms of selective attention

It has been argued that during selection of target objects, irrelevant distractor objects are inhibited (e.g. Tipper, 1985). This article examines whether distractor inhibition is an invariant process that occurs in the same way for each act of selection, or whether it is a flexible process that adjusts to particular behavioural goals. We review previous studies and report new experiments that demonstrate that inhibition is a flexible process. Those internal representations of the distractor that are most associated with the action to be directed toward the target are inhibited. Other properties of the ignored object can remain in an active state and can facilitate subsequent behaviour.     

A HIERARCHICAL CONSTRUCT OF SELF-MANAGEMENT LEADERSHIP AND ITS RELATIONSHIP TO QUALITY OF WORK LIFE AND PERCEIVED WORK GROUP EFFECTIVENESS

This study validates the self-management leadership theory as operationalized by the Self-Management Leadership Questionnaire (Manz & Sims, 1987) in a large telephone company. The sample for this study is 390 self-managing and 412 traditionally managed employees and 94 external leaders from 58 self-managing and 60 traditionally managed teams. Results support Manz and Sims' 6-factor pattern at the first-order level, and in addition, identify a common second-order factor. The hierarchical factor structure is invariant in employee and leader samples drawn from both self-managing and traditionally managed work teams, suggesting that the construct of self-managing leadership is similar for members and leaders of both types of teams. Respondents perceive slightly more self-management leadership behaviors in the self-managing than the traditional work teams. Respondents evaluate self-managing work teams as more effective than traditional work teams, and this difference is moderate in size. Self-managing leadership behaviors are positively associated with QWL (mainly employee satisfaction) and self-rated effectiveness for both self-managing and traditional teams. In general, self-managing work teams are not that different from traditionally managed groups in the relationship of self-managing leadership to outcomes. We conclude that self-management leadership is a hierarchical concept, constituted of specific strategies as well as a general orientation toward empowering employees. These leadership behaviors are applicable to managing both traditional and self-managing work teams.     

Diagnostic morbidity and its relationship to severity of ideation for a nonpsychiatric sample of chronic and severe suicide ideators

This study examined the relationships of frequency and type of psychiatric diagnosis to suicidality within a sample of chronically and severely ideating college-aged students (N=78). The most common diagnoses were the depressive disorders, comprising 43% of all diagnoses, followed by anxiety disorders, comprising 17% of all diagnoses. Retrospective reports of childhood diagnoses were also quite common, comprising 38% of all diagnoses. Number of psychiatric diagnoses was significantly correlated with severity of suicidal ideation (r=.27,p<.02). Hierarchical regression analyses revealed that retrospective childhood diagnoses of attention deficit hyperactivity disorder (ADHD) and separation anxiety disorder significantly predicted 19% of the variance in severity of suicidal ideation after controlling for current diagnoses of major depression and PTSD. When entry of childhood and current diagnoses were reversed, PTSD significantly predicted 4% of the variance in severity of suicidal ideation, while major depression was rendered nonsignificant. Severe suicide ideation, therefore, may be a product of early psychological problems as well as the number of such problems.     

Classifying ℵo-Categorical Theories II: The Existence of Finitely Axiomatizable Proper Class II Theories

Clark and Krauss [1977] presents a classification of complete, satisfiable and _o-categorical theories in first order languages with finite non-logical vocabularies. In 1988 the first author modified this classification and raised three questions about the distribution of finitely axiomatizable theories. This paper answers two of those questions.     

Homogeneous and Universal Dedekind Algebras

A Dedekind algebra is an order pair (B, h) where B is a non-empty set and h is a similarity transformation on B. Each Dedekind algebra can be decomposed into a family of disjoint, countable subalgebras called the configurations of the algebra. There are ₀ isomorphism types of configurations. Each Dedekind algebra is associated with a cardinal-valued function on called its configuration signature. The configuration signature counts the number of configurations in each isomorphism type which occur in the decomposition of the algebra. Two Dedekind algebras are isomorphic iff their configuration signatures are identical. It is shown that configuration signatures can be used to characterize the homogeneous, universal and homogeneous-universal Dedekind algebras. This characterization is used to prove various results about these subclasses of Dedekind algebras.