On individuals in branching histories

Against the background of the theory of branching space-times (BST), the paper sketches a concept of individuals. It discusses Kripkean modal intuitions concerning individuation, and, finally it addresses Lewis??s objections to branching individuals.     

Causation Without Influence

David Lewis’s latest theory of causation defines the causal link in terms of the relation of influence between events. It turns out, however, that one event’s influencing another is neither a necessary nor sufficient condition for its being a cause of that event. In the article one particular case of causality without influence is presented and developed. This case not only serves as a counterexample to Lewis’s influence theory, but also threatens earlier counterfactual analyses of causation by admitting a particularly troublesome type of preemption. The conclusion of the article is that Lewis’s influence method of solving the preemption problem fails, and that we need a new and fresh approach to the cases of redundant causation if we want to hold on to the counterfactual analysis of causation.     

Second order propositional operators over cantor space

We consider propositional operators defined by propositional quantification in intuitionistic logic. More specifically, we investigate the propositional operators of the formA* :p q(p A(q)) whereA(q) is one of the following formulae: (¬¬q q) V ¬¬q, (¬¬q q) (¬¬q V ¬q), ((¬¬q q) (¬¬q V ¬q)) ((¬¬q q) V ¬¬q). The equivalence ofA*(p) to ¬¬p is proved over the standard topological interpretation of intuitionistic second order propositional logic over Cantor space.We relate topological interpretations of second order intuitionistic propositional logic over Cantor space with the interpretation of propositional quantifiers (as the strongest and weakest interpolant in Heyting calculus) suggested by A. Pitts. One of the merits of Pitts' interpretation is shown to be valid for the interpretation over Cantor space.Presented byJan Zygmunt     

Causes,Conditions and Counterfactuals

The article deals with one particular problem created by the counterfactual analysis of causality à la Lewis, namely the context-sensitivity problem or, as I prefer to call it, the background condition problem. It appears that Lewis’ counterfactual definition of causality cannot distinguish between proper causes and mere causal conditions – i.e. factors necessary for the effect to occur, but commonly not seen as causally efficacious. The proposal is put forward to amend the Lewis definition with a condition, based on the notion of cotenability, which would eliminate the problem. It is shown that the corrected definition of causality leads to the transitivity of the causal relation. Possible objections to the proposed solution, involving the assumption of indeterminism and the preemption cases, are given a thorough consideration.     

Differential involvement of the central amygdala in appetitive versus aversive learning

Understanding the function of the distinct amygdaloid nuclei in learning comprises a major challenge. In the two studies described herein, we used c-Fos immunolabeling to compare the engagement of various nuclei of the amygdala in appetitive and aversive instrumental training procedures. In the first experiment, rats that had already acquired a bar-pressing response to a partial food reinforcement were further trained to learn that an acoustic stimulus signaled either continuous food reinforcement (appetitive training) or a footshock (aversive training). The first training session of the presentation of the acoustic stimulus resulted in significant increases of c-Fos immunolabeling throughout the amygdala; however, the pattern of activation of the nuclei of the amygdala differed according to the valence of motivation. The medial part of the central amygdala (CE) responded, surprisingly, to the appetitive conditioning selectively. The second experiment was designed to extend the aversive versus appetitive conditioning to mice, trained either for place preference or place avoidance in an automated learning system (INTELLICAGE). Again, much more intense c-Fos expression was observed in the medial part of the CE after the appetitive training as compared to the aversive training. These data, obtained in two species and by means of novel experimental approaches balancing appetitive versus aversive conditioning, support the hypothesis that the central nucleus of the amygdala is particularly involved in appetitively motivated learning processes.     

A preliminary psychometric evaluation of the Hospital Anxiety and Depression Scale (HADS) in 963 people living with a spinal cord injury

This study aimed to evaluate the preliminary psychometric properties of the Hospital Anxiety and Depression Scale (HADS) in a community sample of adults living with a spinal cord injury (SCI). A cross-sectional design was used with 963 people living in the community with an SCI. Participants were recruited via three spinal centres in the United Kingdom. They completed the HADS and the Life Satisfaction Questionnaire. Psychometric analyses were conducted for the whole sample, by gender and level of injury. The HADS demonstrated good internal consistency, with promising content validity. Two factors, approximating to anxiety and depression were extracted via factor analysis for the whole sample, by gender and level of injury. In line with existing literature, females scored significantly higher than males on the anxiety subscale. Item 7 ("I can sit at ease and feel relaxed") was found to be a complex item, with a potentially different meaning within this population. This study presents preliminary findings, which support the psychometric integrity of the HADS within an outpatient population with SCI. Items that included potential somatic components revealed a more complex factor loading profile. Recommendations are made to further investigate this measure with amendments to such items, incorporating inpatients and independent measures of anxiety and depression to address validity directly.     

Social modulation of learning in rats

It is well known that emotions participate in the regulation of social behaviors and that the emotion displayed by a conspecific influences the behavior of other animals. In its simplest form, empathy can be characterized as the capacity to be affected by and/or share the emotional state of another. However, to date, relatively little is known about the mechanisms by which animals that are not in direct danger share emotions. In the present study, we used a model of between-subject transfer of fear to characterize the social interaction during which fear is transmitted, as well as the behavioral effects of socially transmitted fear. We found that (1) during social interaction with a recently fear-conditioned partner, observers and demonstrators exhibit social exploratory behaviors rather than aggressive behaviors; (2) learning and memory in a shock-motivated shuttle avoidance task are facilitated in rats that underwent a social interaction with a partner that had been fear conditioned; and (3) a brief social interaction with a recently fear-conditioned partner immediately before fear conditioning increases conditioned freezing measured on the next day. The observed effects were not due to a stress-induced increase in pain sensitivity or analgesia. Collectively, these data suggest that a brief social interaction with a cage mate that has undergone an aversive learning experience promotes aversive learning in an otherwise naïve animal. We argue that socially transferred fear is an adaptation that promotes defensive behavior to potentially dangerous situations in the environment.Human empathy can be defined as the ability to experience and share the thoughts and feelings of others (de Waal 2008). Obviously, this is a complex social phenomenon that, until recently, has received much attention from philosophers and psychologists rather than neuroscientists (Decety and Lamm 2006). However, in its simplest form, empathy can be characterized as the capacity to be affected by and/or share the emotional state of another (de Waal 2008). Tuning one''s emotional state to that of another increases the probability of similar behavior, which thereby allows rapid adaptation to environmental challenges (Hatfield et al. 1994). This social adaptation may be particularly important for emotions that signal a potential danger, such as fear. Although one can learn about potentially harmful stimuli by directly experiencing an aversive event, observation or interaction with a conspecific in danger and/or in pain may also provide information about threats in the environment. There is a vast literature on learning about direct danger (Maren 2001) as well as sharing emotions through observation (see, e.g., Church 1959; Langford et al. 2006; Olsson and Phelps 2007). However, relatively little is known about the mechanisms by which animals that are not in a direct danger share emotions.We have recently designed an experimental rat model of between-subject transfer of emotional information (Knapska et al. 2006). In this model, rats are housed in pairs and one member of the pair (the “demonstrator”) is removed and subjected to fear conditioning. After the fear-conditioning episode, the conditioned animal is allowed to interact with its naïve cage mate (the “observer”). We showed that the demonstrator''s fear is socially transferred to the observer, resulting in both rapid increase in exploratory behavior of the observer and a pattern of c-Fos activation in the observer''s amygdala that parallels that of the shocked demonstrators.These results suggest that the social interaction between the demonstrator and observer results in a transfer of information that promotes aversively motivated learning in the observer. However, the nature of the social interaction and how it comes to influence aversively motivated behavior is not known. Therefore, the present study aimed to characterize the behavior of both the demonstrators and observers during their social interaction and further characterize the nature of the influence of socially transmitted fear on aversively motivated learning and memory. We hypothesized that the social interaction between observers and demonstrators would result in a social transfer of fear that would promote learning and memory of both active defensive responses (avoidance) as well as defensive immobility (freezing). To test this hypothesis, we carried out five experiments that examined the nature of the social interaction between shocked demonstrators and observers (Experiment 1), the acquisition and retention of active avoidance (Experiment 2), and conditioned freezing (Experiment 3). Because it is not clear if social transfer effects can be observed among unfamiliar animals and to control for social buffering, we also compared the social transfer of fear in familiar and unfamiliar rats (Experiment 4). To control for the possible influence of different pain sensitivity thresholds in the observers paired with shocked demonstrators, we carried out pain tests (Experiment 5).     

Are Some Psychotherapies Much More Effective Than Others?

In a previous paper we had reported on the examination of comparisons of 18 metaanalyses of active treatments with each other (Luborsky, Rosenthal, Diguer, et al., 2001). These metaanalyses gave a small and nonsignificant mean level of difference between types of treatments. The smallness of this correlation confirms Rosenzweig's (1936) expectation that because of the large overlap in effective ingredients of different psychotherapies, comparative studies of psychotherapies would show little difference. Such a comparison that includes psychoanalyses seems a long way off, but if outcomes of psychoanalyses are defined similarly to those in the other psychotherapies, the expected differences in outcomes may also be small.