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.     

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.     

A developmental evaluation of the role of word shape in word recognition

Fourth- and seventh-grade children and college-age adults proofread passages typed either in lowercase or in all capital letters. Words were misspelled by deleting one of four letters, s, c, k, or p, that have similar features in lowercase and uppercase. Proofreading errors decreased with age and increasing reading ability, but all of the subjects were sensitive to changes in word shape--they missed more words with deletions of s or c than k or p in the lowercase passage but not in the all-capitals passage. These findings indicate that word shape is an important variable in recognizing familiar words, even for young readers.     

The role of inhibition in a spreading-activation model of language production. II. The simulational perspective

This is the second part of a project aimed at establishing the role of lateral inhibition in spreading-activation models of language production. While the first part (Berg &; Schade, 1992) reviewed the psycholinguistic evidence for inhibition and established that indeed inhibition takes place, this paper addresses the issue from the implementational perspective. A series of computer simulations are reported in which spreading-activation models with or without inhibition are directly contrasted. The performance of the competing models is evaluated against two sets of criteria. On the more technical side, the “heat death” and the selection problems have to be solved. That is, the target must have a high and the nontarget units a low level of activation. Additionally, there are certain empirical effects from the production literature which may serve as test cases for deciding between the rival models. The results of the simulations indicate that only the inhibition-based model proves capable of meeting all challenges. All inhibitionless variants fail in one or more respects. It is further shown that the need for the inhibitory component increases with the size of the processing network and that one well-known production model can do without lateral inhibition only at the expense of introducing a concept which resembles inhibition in its effect but cannot replace it.     

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.     

The tunnel effect,Gibson's perception theory,and reflective seeing

Summary Subjects can have continuous visual experience of an object's movement across a display though the movement's middle phase takes place behind an opaque screen. The present article considers explanatory issues pertaining to this so-called, tunnel effect, with special reference to Gibson' s perception theory and the visual activity that I have been calling reflective seeing. Among the issues discussed are the following. (a) In the tunnel experiments, I suggest, there occur both persisting perception, as Michotte held, and persistence perception, as Gibson held. The subjects pick up stimulus information that allows visually experiencing the object's going out of sight at one edge of the screen and coming back into sight at another edge of the screen; the subjects have visual experience of the continued existence and movement of the object while it is out of sight. Moreover, persistence of perceptual experience is involved: when the object goes out of sight, the subjects' visual experience of its movement goes on. (b) I also argue that the tunnel effect is a phenomenon of both straightforward and reflective seeing. Adopting a phenomenal attitude, as one does when reporting one's perceptual experience, one still sees movement taking place on the other side of the screen, as one does in straightforward seeing. However, whereas straightforward seeing does not give inner awareness of visual experience, the subjects in the tunnel experiments report visually experiencing the object's movement while also visually experiencing the opaque screen in front of it as opaque. I argue that these reports, and those about the object's going out of and coming back into sight, must be based on the kind of visual experience that is part and product of reflective seeing.     

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.