Revision algebra semantics for conditional logic

The properties of belief revision operators are known to have an informal semantics which relates them to the axioms of conditional logic. The purpose of this paper is to make this connection precise via the model theory of conditional logic. A semantics for conditional logic is presented, which is expressed in terms of algebraic models constructed ultimately out of revision operators. In addition, it is shown that each algebraic model determines both a revision operator and a logic, that are related by virtue of the stable Ramsey test.The author is grateful for a correction and several other valuable suggestions of two anonymous referees. This work was supported by the McDonnell Douglas Independent Research and Development program.     

Partial monotonicity and a new version of the Ramsey test

We introduce two new belief revision axioms: partial monotonicity and consequence correctness. We show that partial monotonicity is consistent with but independent of the full set of axioms for a Gärdenfors belief revision sytem. In contrast to the Gärdenfors inconsistency results for certain monotonicity principles, we use partial monotonicity to inform a consistent formalization of the Ramsey test within a belief revision system extended by a conditional operator. We take this to be a technical dissolution of the well-known Gärdenfors dilemma.In addition, we present the consequential correctness axiom as a new measure of minimal revision in terms of the deductive core of a proposition whose support we wish to excise. We survey several syntactic and semantic belief revision systems and evaluate them according to both the Gärdenfors axioms and our new axioms. Furthermore, our algebraic characterization of semantic revision systems provides a useful technical device for analysis and comparison, which we illustrate with several new proofs.Finally, we have a new inconsistency result, which is dual to the Gärdenfors inconsistency results. Any elementary belief revision system that is consequentially correct must violate the Gärdenfors axiom of strong boundedness (K^*8), which we characterize as yet another monotonicity condition.This work was supported by the McDonnell Douglas Independent Research and Development program.     

The representation and integration in memory of spatial and nonspatial information

A series of experiments investigated whether people could integrate nonspatial information about an object with their knowledge of the object's location in space. In Experiments 1 and 3, subjects learned the locations of cities on a fictitious road map; in Experiments 2, 4, and 5, subjects were already familiar with the locations of buildings on a campus. The subjects then learned facts about the cities on the maps or the buildings on the campus. The question of interest was whether or not these nonspatial facts would be integrated in memory with the spatial knowledge. After learning the facts, subjects were given a location-judgment test in which they had to decide whether an object was in one region of the space or another. Knowledge integration was assessed by comparing levels of performance in two conditions: (a) when a city or a building name was primed by a fact about a neighboring city or building, and (b) when a city or a building name was primed by a fact about a distant city or building. Results showed that responses in Condition a were faster or more accurate, or both faster and more accurate, than responses in Condition b. These results indicate that the spatial and nonspatial information were encoded in a common memory representation.     

Acoustic analysis in the differentiation of Parkinson's disease and major depression

In its early stages, Parkinson's disease (P.D.) may be difficult to distinguish from major depression (M.D.) leading to inappropriate management. Both illnesses are characterized by psychomotor retardation. The neurovegetative symptoms used to diagnose M.D. are not specific and in P.D. may be due to the physical illness itself. Currently, differentiation of the two disorders relies on subjective clinical observation. Improved diagnostic accuracy based on more objective data is needed. To this end, this study used computerized acoustic analysis to contrast speech patterns in P.D. and M.D. The sample consisted of 30 P.D. patients without depression or dementia, 30 patients with uncomplicated M.D., and 31 normal controls, each 60 years of age or over. Of the acoustic variables studied, M.D. patients had significantly reduced rates of speech compared with P.D. patients. The data suggest that this temporal measure of speech may be useful in the differentiation of P.D. and M.D.     

Context-dependent variation in social stereotyping 1: The effects of intergroup relations as mediated by social change and frame of reference

During the 1990-1991 Persian Gulf conflict an experiment was conducted with Australian university students (N = 200) to investigate whether the social stereotyping of Americans varied with social contextual manipulations related to the hostilities. The study, conducted in two phases at the start and end of the conflict, examined how the assignment of standard stereotypical traits to Americans was affected (a) by the large-scale social change constituted by the war and (b) by variation in the frame of reference provided by relevant comparison groups. The elicited stereotypes were sensitive to both of these contextual variables, demonstrating significant variation and fluidity. Overall, stereotypes of Americans were relatively negative. They were significantly more negative (a) at the end of the war than at the beginning in the restricted frame (when Australia and Britain were comparison groups) and (b) in the first phase of the conflict when the frame was extended to include Iraq as a comparison group. The findings were in line with expectations derived from self-categorization theory (Turner, 1985) that the social categorization of self and other into ingroup and outgroup is inherently variable, comparative and context-dependent. They question the long-held view of stereotypes as fixed, rigid and resistant to change.     

Context-dependent variation in social stereotyping 2: The relationship between frame of reference,self-categorization and accentuation

This paper examines the hypothesis that patterns of stereotypic accentuation reflect the degree to which judged stimuli share the same social category membership as the stereotyper, Following self-categorization theory, the degree of this shared identity is operationalized in terms of the meta-contrast ratio as a function of the positions of (a) stereotyper and (b) stereotyped target relative to (c) the stereotyper's frame of reference. Three experiments are reported which sought to manipulate shared category membership either by extension of subjects' frame of reference or by extremitization of target and subject with respect to that frame. As predicted, greater shared identity was associated with stronger assimilation of the target to subjects' own position and with change in stereotype content. Findings are discussed in relation to theories of personality, social judgement and social cognition. Like the accentuation processes which underpin them, it is proposed that stereotypes are sensitive to comparative context and that they reflect veridically the social self-categorical properties of stimuli.     

Mentality and causality

I am grateful to John Bickle, Jaegwon Kim, Brian McLaughlin, and, most especially, to my colleague, Alfred Mele, for much helpful discussion on the topic of intentional causation.     

Ethical Issues in Counselling and Pastoral Care

The historical and contemporary context of pastoral care and counselling within the judaeo/Christian tradition is reviewed. Three kinds of pastors who use counselling in their work - Christian, specialist, and generic - are identified and the ethical problems of their positions clarified. The ethical principles of autonomy, beneficence, non-maleficence and justice are applied to the counselling work of pastors. Theology's definition of various ethical levels, and the impact of these upon the professional ethics of pastoral carers and counsellors, are explored, and some conclusions for the future drawn.     

An exploratory study of videotapes of long-term group psychotherapy of outpatients with major and chronic mental illness

This study explored patterns emerging in videotaped sessions of group psychotherapy with seven outpatients of a large mental health facility. The 22 sessions spanned the 12th to 27th months of the group's existence. Group members had long histories (25–50 years) of symptoms characteristic of schizophrenia. Each session was rated on the Group Environment Scale. One session from a group in its earlier stages was also rated on the same instrument to give some indication of baseline patterns. Analyses of changes across the 15 months were not statistically significant. However, some GES subscales, including Cohesion, Independence, and Self-Discovery, showed relatively high mean levels across the 15-month period. These elevations are discussed as suggesting the codevelopment of orientations that have sometimes been viewed as incompatible and unattainable for schizophrenics. Interpreted clinically, the GES patterns help to elaborate recent findings about the relatively good success of long-term group therapy with such populations. The study, although merely suggestive, illustrates the potential for gleaning solid and clinically useful data from group psychotherapy research.The authors would like to thank Drs. Jill Rierdan, Nina Fieldsteel, Joseph Christy, and an anonymous reviewer for their suggestions, Kendra Bryant for serving as the reliability rater, and Janet Eltinge for her skilled videotaping.     

Prejudice and behavior: A review

Originally it was thought that prejudiced intergroup attitudes were very closely related to negative intergroup behavior. More recently, empirical studies reveal a weak and inconsistent relationship, that discriminatory intergroup behavior is therefore largely determined by situational factors, and that it is relatively independent of an individual’s attitudes. A detailed review of this research, however, suggests that the relationship between prejudice and behavior may be much more consistent than has been thought. Moreover, although the relationship is usually not very powerful, most research has involved methodological inadequacies which would have inappropriately depressed it. Finally, it is noted that, for negative intergroup behavior to be situationally determined, does not exclude a strong relationship between it and prejudiced attitudes.