Eine Pseudofovea bei Hemianopikern

Ohne Zusammenfassung     

Walking a Tightrope: The Jesuit Robert Bütler and Muslim–Christian Dialogue in Pakistan

This article deals with the Swiss Jesuit Robert Andreas Bütler (1915–1996) and his attempts to develop Muslim–Christian dialogue in Pakistan between the 1960s and 1980s. It focuses especially on his correspondence with the Islamist ideologue Sayyid Abu ’l-A?la Mawdudi (1903–1979), one of the most influential Muslim thinkers of the twentieth century and a major figure in South Asian Islam. On the basis of their written exchange, the article identifies challenges to Muslim–Christian rapprochement against the backdrop of state-funded Islamization and rising political tensions in Pakistan. It demonstrates how Bütler’s efforts became entangled in postcolonial struggles for a national identity, thereby revealing the limits of Vatican II-inspired approaches to Muslim–Christian dialogue.     

The effect of social learning on avoidance of aposematic prey in juvenile great tits (<Emphasis Type="Italic">Parus major</Emphasis>)

Social learning plays an important role in acquiring new foraging skills and food preferences in many bird species but its potential role in learning to avoid aposematic prey has never been studied. We tested the effect of social learning on the acquisition of avoidance of aposematic insect prey (firebug Pyrrhocoris apterus; Heteroptera) in juvenile, hand-reared great tits (Parus major). Behaviour towards aposematic prey was compared between two groups of birds: (1) the observers that were, prior to encounter with firebugs, allowed to watch the experienced conspecific demonstrator repeatedly refuse to attack the prey, and (2) the control birds that lacked this opportunity. Observing an experienced demonstrator was not sufficient for learning complete avoidance, because birds from both groups attacked at least the first firebug they had encountered in avoidance training. However, the opportunity to observe the avoidance behaviour of another bird significantly increased the rate of subsequent individual learning of observers in comparison with control birds. Social learning also decreased mortality of firebugs killed by the birds during the avoidance learning. Socially enhanced learning to avoid aposematic prey might be a mechanism important especially for naive juvenile birds learning from their parents, but it could also enhance learning in adults from their more experienced flock mates. Because social learning of avoidance may also lead to decreased mortality of aposematic prey, its effect should be taken into account in scenarios considering evolution and maintenance of prey warning signals.     

The neural basis of event-time introspection

We explored the neural mechanisms allowing humans to report the subjective onset times of conscious events. Magnetoencephalographic recordings of neural oscillations were obtained while human subjects introspected the timing of sensory, intentional, and motor events during a forced choice task. Brain activity was reconstructed with high spatio-temporal resolution. Event-time introspection was associated with specific neural activity at the time of subjective event onset which was spatially distinct from activity induced by the event itself. Different brain regions were selectively recruited for introspection of different event types, e.g., the bilateral angular gyrus for introspection of intention. Our results suggest that event-time introspection engages specific neural networks to assess the contents of consciousness. Subjective event times should therefore be interpreted as the result of complex interactions between introspection and experience networks, rather than as direct reproduction of the individual’s conscious state or as a mere post hoc interpretation.     

Tits use amodal completion in predator recognition: a field experiment

Amodal completion enables an animal to perceive partly concealed objects as an entirety, and to interact with them appropriately. Several studies, based upon either operant conditioning or filial imprinting techniques, have shown that various animals (both mammals and birds) can perform amodal completion. Before this study, the use of amodal completion by untrained animals in the recognition of objects had not been considered. Using two feeders, we observed in a field experiment the reaction of tits to the torso of a sparrowhawk (partly occluded or an ‘amputated’ dummy) in two different treatments (sparrowhawk torso vs. complete dummy pigeon; and torso vs. complete dummy sparrowhawk). It is clear that the birds considered the two torso variants as predators and kept away from both of them when the second feeder offered a ‘pigeon’ instead. On the other hand, when a ‘complete sparrowhawk’ was present on the second feeder, the number of visits to the occluded torso remained low; while the number of visits to the amputated one increased threefold. Birds risked perching near what was clearly an amputated torso; while the fear of a “hiding” (occluded) torso remained unchanged, when the second feeder did not provide a safe alternative. Such discrimination between torsos requires the ability for amodal completion. Our results demonstrate that in their recognition process, the birds not only use simple sign stimuli, but also complex cognitive functions.     

The rubber hand illusion depends on a congruent mapping between real and artificial fingers

The rubber hand illusion (RHI), in which a visible artificial hand is touched (or moves) synchronously with the participant's unseen own hand, indicates that body representations can undergo rapid changes. While several constraints for this illusion have been described, some reports highlight a remarkable flexibility of body representations, even contradicting a priori assumptions regarding body appearance and anatomy (e.g., the subjective embodiment of a third arm).     

Gamma oscillations distinguish true from false memories

ABSTRACT— To test whether distinct patterns of electrophysiological activity prior to a response can distinguish true from false memories, we analyzed intracranial electroencephalographic recordings while 52 patients undergoing treatment for epilepsy performed a verbal free-recall task. These analyses revealed that the same pattern of gamma-band (28–100 Hz) oscillatory activity that predicts successful memory formation at item encoding—increased gamma power in the hippocampus, prefrontal cortex, and left temporal lobe—reemerges at retrieval to distinguish correct from incorrect responses. The timing of these oscillatory effects suggests that self-cued memory retrieval begins in the hippocampus and then spreads to the cortex. Thus, retrieval of true, as compared with false, memories induces a distinct pattern of gamma oscillations, possibly reflecting recollection of contextual information associated with past experience.     

Condorcet and communitarianism: Boghossian’s fallacious inference

This paper defends the communitarian account of meaning against Boghossian’s (Wittgensteinian) arguments. Boghossian argues that whilst such an account might be able to accommodate the infinitary characteristic of meaning, it cannot account for its normativity: he claims that, since the dispositions of a group must mirror those of its members, the former cannot be used to evaluate the latter. However, as this paper aims to make clear, this reasoning is fallacious. Modelling the issue with four (justifiable) assumptions, it shows that Condorcet’s ‘Jury Theorem’ can be used to prove that the dispositions of the majority of the members of a group can differ from those of any individual member in a way that makes it possible to use communal dispositions as a standard with which individual dispositions can be assessed. Moreover, the argument of the paper is also shown to have general implications for the use of formal methods in the explanation of the nature of certain fallacious inferences.