Interrogative Belief Revision in Modal Logic

The well known AGM framework for belief revision has recently been extended to include a model of the research agenda of the agent, i.e. a set of questions to which the agent wishes to find answers (Olsson & Westlund in Erkenntnis, 65, 165–183, 2006). The resulting model has later come to be called interrogative belief revision. While belief revision has been studied extensively from the point of view of modal logic, so far interrogative belief revision has only been dealt with in the metalanguage approach in which AGM was originally presented. In this paper, I show how to model interrogative belief revision in a modal object language using a class of operators for questions. In particular, the solution I propose will be shown to capture the notion of K-truncation, a method for agenda update in the case of expansion constructed by Olsson & Westlund. Two case studies are conducted: first, an interrogative extension of Krister Segerberg’s system DDL, and then a similar extension of Giacomo Bonanno’s modal logic for belief revision. Sound and complete axioms will be provided for both of the resulting logics.     

Young children's selective learning of rule games from reliable and unreliable models

We investigated preschoolers’ selective learning from models that had previously appeared to be reliable or unreliable. Replicating previous research, children from 4 years selectively learned novel words from reliable over unreliable speakers. Extending previous research, children also selectively learned other kinds of acts – novel games – from reliable actors. More important, – and novel to this study, this selective learning was not just based on a preference for one model or one kind of act, but had a normative dimension to it. Children understood the way a reliable actor demonstrated an act not only as the better one, but as the normatively appropriate or correct one, as indicated in both their explicit verbal comments and their spontaneous normative interventions (e.g., protest, critique) in response to third-party acts deviating from the one demonstrated. These findings are discussed in the broader context of the development of children's social cognition and cultural learning.     

The nonverbal manifestations of cognitive processes in clinical listening

Nonverbal behaviors were observed during communicative sequences in videotaped clinical interviews. The interviews were conducted by two groups of physicians-in-training with contrasting cognitive profiles as determined by well-known laboratory tasks prior to the interviews. In each phase of the communicative sequences, significant differences emerged between the two groups for various types of nonverbal behaviors. Differences also emerged between the two groups of interviewers in their questioning patterns and in the nature of the narrative elicited from their interlocutors. A correlational analysis revealed consistent patterns of behaviors across phases of the communicative sequences. The findings provide additional evidence for the intimate connection between nonverbal behavior and cognitive activity and point to nonverbal behaviors as objective measures of the processes underlying clinical listening.     

Dynamics of hostile aggression: Influence of anger,hurt instructions,and victim pain feedback

The research basically examined some of the dynamics of hostile aggression by looking at the effects of different Buss procedure instructions and levels of victim pain feedback on the aggressive behavior of angered and nonangered men. In a 2 × 2 × 2 completely crossed factorial experiment, male undergraduates were initially either angered or not by an experimental accomplice. When later given the ostensible opportunity to administer shocks to the same accomplice in a typical Buss procedure, the subjects were either told that longer and more intense shocks would probably interfere with the person's learning as well as causing him more pain (hurt instructions) or given no information about the effects of shocks on learning (standard instructions). Finally, after each shock they administered, the subjects were provided with either high or low victim pain feedback. The angered men were significantly more aggressive than their nonangered counterparts, and a significant interaction between anger and instructions indicated this was especially true for the men given hurt instructions. Significant interactions between the other independent variables and trial blocks revealed that the angered men, particularly those receiving hurt instructions and high victim pain feedback, displayed the greates increases in aggression. The results provide qualified support for the derived proposition about hostile aggression that signs and/or knowledge of victim injury and pain can stimulate more intense aggression from angry individuals.     

An experimental evaluation of tokens as conditioned reinforcers in retarded children

Since the publication of experimental reports by Wolfe (1936) and Cowles (1937), that tokens could be established as conditioned reinforcers, many accounts have appeared on the implementation of token systems in human subjects. Tokens have been successfully used as prosthetic motivational devices in a great variety of situations and subjects, such as retarded children (Birnbrauer, Wolf, Kidder and Tague, 1965), adult psychotics (Ayllon and Azrin, 1969), delinquent children and adolescents (Tyler, 1967; Phillips and Wolf, 1968), low achievers in schools (Clark, Lachowicz and Wolf, 1968), emotionally disturbed children (Hewett, Taylor and Artuso, 1969) and in normal classroom settings (O'Leary, Becker, Evans and Saudargas, 1969). In these reports, administration of tokens usually produced an increase in the frequency of desirable social and productive behavior. However, none of these studies showed that the effect of the tokens depended on their role as conditioned reinforcers based on the standard exchange systems being used. No assessment was provided about the separate contribution of the social reinforcement operations involved in dispensing tokens in a social setting.A suggestion about the possible confounding effects of social reinforcement in token administration comes from the failure to establish token systems in subjects who are partially unresponsive to social reinforcement (Hamblin et al., 1970; Ribes and Souza e Silva, in preparation). The present research was conducted with the aim of isolating the effects of conditioned reinforcement as such—apart from those produced by the social reinforcement provided in the delivery of tokens.     

Visual working memory in young children

Five experiments investigated immediate memory for drawings of familiar objects in children of different ages. The aims were to demonstrate younger children’s greater dependence on visual working memory and to explore the nature of this memory system. Experiment 1 showed that visual similarity of drawings impaired recall in young (5-year-old) children but not in older (10-year-old) children. Experiment 2 showed that younger and older children were affected in contrasting ways when the temporal order of recall was manipulated. Experiment 3 explored a recency effect found in backward recall and investigated its sensitivity to the presentation modality of materials used to produce retroactive interference (RI). For younger children, recency was reduced by visual but not by auditory-verbal RI; for older children, recency was more sensitive to auditoryverbal RI. Experiment 4 confirmed the effect of visual RI on visual recency in young children and showed that the same RI had little effect on their recall of spoken words. These results confirm younger children’s dependence on visual working memory. A final experiment showed that the effects of visual similarity and visual RI are additive, suggesting that they reflect different modes of accessing stored visuospatial information. Implications of these findings for developmental issues and for the nature of visual working memory are discussed.     

On objectivity

The following definition of objective is proposed: A statement S is objective if and only if in S all parameters that are relevant to its truth value are made explicit. The objectivity of predicates and relations can be defined in a similar manner. This simple conception of objectivity-which could be called explicitness conception of objectivity-can be found in Hermann Weyl and plays a central part in the natural sciences. There are grades of objectivity depending on the quality and the number of parameters our predicates are relativized to A relativistic Ockham principle has to be recognized: Relativization parameters are not to be multiplied beyond necessity. The explicitness conception of objectivity is accessible to mathematical specifications, is the core of the idea of invariance, has a lot of philosophical applications and leads to precise notions of subjectivity and a precise formulation of the problem of the limits of objectivity.I am grateful to Andreas Bartels, Ulrich Gähde, Mark Helme, Andreas Kamlah, Andreas Kemmerling, Winfred Klink, Toni Koch, Hilary Putnam and Matthias Varga von Kibéd who have, in one way or another, contributed to the present content and form of this paper.