Supervaluation-Style Truth Without Supervaluations

Kripke’s theory of truth is arguably the most influential approach to self-referential truth and the semantic paradoxes. The use of a partial evaluation scheme is crucial to the theory and the most prominent schemes that are adopted are the strong Kleene and the supervaluation scheme. The strong Kleene scheme is attractive because it ensures the compositionality of the notion of truth. But under the strong Kleene scheme classical tautologies do not, in general, turn out to be true and, as a consequence, classical reasoning is no longer admissible once the notion of truth is involved. The supervaluation scheme adheres to classical reasoning but violates compositionality. Moreover, it turns Kripke’s theory into a rather complicated affair: to check whether a sentence is true we have to look at all admissible precisification of the interpretation of the truth predicate we are presented with. One consequence of this complicated evaluation condition is that under the supervaluation scheme a more proof-theoretic characterization of Kripke’s theory becomes inherently difficult, if not impossible. In this paper we explore the middle ground between the strong Kleene and the supervaluation scheme and provide an evaluation scheme that adheres to classical reasoning but retains many of the attractive features of the strong Kleene scheme. We supplement our semantic investigation with a novel axiomatic theory of truth that matches the semantic theory we have put forth.     

Do chimpanzees anticipate an object’s weight? A field experiment on the kinematics of hammer-lifting movements in the nut-cracking Taï chimpanzees

When humans are about to manipulate an object, our brains use visual cues to recall an internal representation to predict its weight and scale the lifting force accordingly. Such a long-term force profile, formed through repeated experiences with similar objects, has been proposed to improve manipulative performance. Skillful object manipulation is crucial for many animals, particularly those that rely on tools for foraging. However, despite enduring interest in tool use in non-human animals, there has been very little investigation of their ability to form an expectation about an object’s weight. In this study, we tested whether wild chimpanzees use long-term force profiles to anticipate the weight of a nut-cracking hammer from its size. To this end, we conducted a field experiment presenting chimpanzees with natural wooden hammers and artificially hollowed, lighter hammers of the same size and external appearance. We used calibrated videos from camera traps to extract kinematic parameters of lifting movements. We found that, when lacking previous experience, chimpanzees lifted hollowed hammers with a higher acceleration than natural hammers (overshoot effect). After using a hammer to crack open one nut, chimpanzees tuned down the lifting acceleration for the hollowed hammers, but continued lifting natural hammers with the same acceleration. Our results show that chimpanzees anticipate the weight of an object using long-term force profiles and suggest that, similarly to humans, they use internal representations of weight to plan their lifting movements.     

Prevalence and correlates of ICD-11 adjustment disorder: Findings from the Zurich Adjustment Disorder Study

Background/Objective: The 11th revision of the International Classification of Diseases (ICD-11) will provide a new definition of adjustment disorder (AjD). The aim of the present study is to report on prevalence and correlates of ICD-11 AjD in a high-risk sample. Method: Three hundred thirty persons who had lost their job involuntarily were sampled by local job centres. The Munich Composite International Diagnostic Interview was administered with a new AjD module. Associations between AjD and correlates were investigated with logistic regression analyses. Results: 27.3% of the participants reported the AjD core symptom pattern. 13.8% men and 17.2% women met diagnostic guidelines of ICD-11 AjD. Prevalence increased with age and exposure to multiple stressors. The AjD core symptom pattern was associated with various sociodemographic correlates (e. g., lower financial household budget), whereas the full ICD-11 diagnosis including the exclusion algorithm was not. Regarding work-related factors, AjD occurred with a lower probability if the last job position had higher responsibilities and more general confidence for the future. Conclusions: ICD-11 AjD has a high prevalence among persons who lost their jobs involuntarily. Healthcare professionals should be aware of this problem. Research to investigate the ICD-11 AjD concept in the general populations and other subpopulations is needed.     

Book reviews

Abstract

Oakhill, J. &; Garnham, A. (1988). Becoming a skilled reader, Oxford: Blackwell. Pp. 206. ISBN 0-631-15244X £27.50 (hardback), ISBN 0-631-15776X £8.95 (paperback).

Brewin, C. R. (1988). Cognitive foundations of clinical psychology. London: Lawrence Erlbaum Associates Ltd. Pp. 224. ISBN 0-86377-098-3 £24.50 (hardback), ISBN 0-86377-099-1 £8.95 (paperback).     

Episodic retrieval processes take place automatically in auditory negative priming

Episodic retrieval processes involved in negative priming have been argued to be susceptible to the proportion of attended repetition trials. The more trials with the same prime and probe response, the more beneficial should it be to retrieve the prime episode, particularly its response. Retrieval of the prime episode, however, is task-inappropriate for ignored repetition trials, leading to negative priming. Correspondingly, visual negative priming increases with the proportion of attended repetition trials. We tested whether the same is true for the auditory modality. Three attended repetition proportion groups (0–25–50%) showed the same amount of negative priming. All groups committed more prime response errors in ignored repetition than in control trials, implying that prime response retrieval took place. Thus, retrieval processes in auditory negative priming appear to be automatic and cannot be influenced as easily as in the visual domain. In Experiment 2, the proportion of ignored repetition trials was manipulated (25–50–75%) to test whether auditory negative priming can be strategically manipulated at all. Similar to the visual modality negative priming was reduced with increasing proportion of ignored repetition trials. Differences between visual and auditory short-term memory are discussed to account for the results.     

Psychology and the science of human-environment interactions

Psychology has an indispensable role in understanding environmental problems and finding solutions. To fill this role, psychologists must work within an interdisciplinary effort to build a scientific understanding of human-environment interactions. This article enumerates 8 widely held beliefs about these interactions and assesses the strengths and limitations of each belief. It suggests that psychology can contribute more strongly by counteracting disciplinary biases, focusing research where a behavioral analysis identifies major opportunities, making appropriately modest claims, collaborating with other disciplines, and building on psychology's relative strengths among the human sciences.     

Dissociating the effects of automatic activation and explicit expectancy on reaction times in a simple associative learning task

After repeated associations between two events, E1 and E2, responses to E2 can be facilitated either because participants consciously expect E2 to occur after E1 or because E1 automatically activates the response to E2, or because of both. In this article, the authors report on 4 experiments designed to pit the influence of these 2 factors against each other. The authors found that the fastest responses to a target in a reaction time paradigm occurred when automatic activation was highest and conscious expectancy lowest. These results, when considered together with previous findings indicating that, under most conditions, the relation between expectancy and reaction times is in the opposite direction, are indicative of a reversed association-an interaction pattern that J. C. Dunn and K. Kirsner (1988) demonstrated to be the only one that unambiguously points to the involvement of independent processes.     

Mechanisms underlying working memory for novel information

In this Opinion article we describe a theory that the brain mechanisms underlying working memory for novel information include a buffer in parahippocampal cortices. Computational modeling indicates that mechanisms for maintaining novel information in working memory could differ from mechanisms for maintaining familiar information. Electrophysiological data suggest that the buffer for novel information depends on acetylcholine. Acetylcholine activates single-cell mechanisms that underlie persistent spiking of neurons in the absence of synaptic transmission, allowing maintenance of information without prior synaptic modification. fMRI studies and lesion studies suggest that parahippocampal regions mediate working memory for novel stimuli, and the effects of cholinergic blockade impair this function. These intrinsic mechanisms in parahippocampal cortices provide an important alternative to theories of working memory based on recurrent synaptic excitation.     

Normal auditory negative priming in schizophrenic patients

Performance of 28 schizophrenic patients and 28 matched controls was compared in an auditory priming task. A large auditory negative priming effect was obtained for the patients as well as for the control group, and the size of the negative priming effect was approximately the same for both groups. Under the same conditions, positive or repetition priming for the patients was enhanced compared to that of the control group. The present findings from an auditory priming task are consistent with a growing body of evidence from the visual domain showing normal rather than reduced or eliminated negative priming in schizophrenic patients.     

Same-sex couple perceptions of family support: a consensual qualitative study

Few studies have examined the family context in which same-sex couples negotiate their lives and relationships. Consensual qualitative research methods (Hill, Thompson, & Williams, 1997) were used to analyze 14 same-sex couples' conversations about family support. Couples perceived that their families are positively supportive, non-supportive, or ambivalent in their support. These perceptions led to positive or negative emotional reactions in the couple members and to specific coping. The majority of couples perceived that family support (or lack of support) had an effect on the quality of their couple relationship. No general or typical response strategies to lack of family of origin support emerged, suggesting a lack of models or norms for same-sex couples. The implications for psychotherapeutic interventions with same-sex couples are discussed.