Cognitive functions of gamma-band activity: memory match and utilization

Oscillatory neural activity in the gamma frequency range (>30Hz) has been shown to accompany a wide variety of cognitive processes. So far, there has been limited success in assigning a unitary basic function to these oscillations, and critics have raised the argument that they could just be an epiphenomenon of neural processing. We propose a new framework that relates gamma oscillations observed in human, as well as in animal, experiments to two underlying processes: the comparison of memory contents with stimulus-related information and the utilization of signals derived from this comparison. This model attempts to explain early gamma-band responses in terms of the match between bottom-up and top-down information. Furthermore, it assumes that late gamma-band activity reflects the readout and utilization of the information resulting from this match.     

Perceiving minority members as individuals: the effects of relative group size in social categorization

According to the account by comparative distinctiveness, minorities draw attention by virtue of their relative size, leading to more individuation and more stereotyping of their members. Using the ‘Who said what?’ paradigm by Taylor, Fiske, Etcoff, and Ruderman ( 1978 ) in Klauer and Wegener's ( 1998 ) modified version, relative group size of gender categories and age categories was varied in a pilot study and a main experiment, respectively. In the pilot study, memory for discussion statements and in both studies, memory for individuating information increased as subgroup size decreased. Rating measures obtained in the main experiment revealed most stereotyping of minority members. The findings thereby support major predictions of the account by comparative distinctiveness, but demonstrate dissociations between different modes of category‐based processing, i.e. category memory, reconstructive category use, and stereotyping. Copyright © 2002 John Wiley & Sons, Ltd.     

Emergent Individuals

We explain the thesis that human mental states are ontologically emergent aspects of a fundamentally biological organism. We then explore the consequences of this thesis for the identity of a human person over time. As these consequences are not obviously independent of one's general ontology of objects and their properties, we consider four such accounts: transcendent universals, kind-Aristotelianism, immanent universals, and tropes. We suggest there are reasons for emergentists to favour the latter two accounts. We then argue that within such ontologies, emergentism about properties pushes one to the stronger claim that there are emergent individuals, though not individuals which are dual to person's bodies — substance emergentism, but not substance dualism.     

Internistische Psychosomatik

Die psychische Komorbidität internistischer Patienten im Sinne einer ICD-Diagnose des Kapitels F beträgt mehr als 35%: Neurotische, besonders somatoforme, Schmerz-, affektive Störungen und Suchterkrankungen sind häufig. Die Liegedauer ist bei psychischer Komorbidität deutlich erhöht. Es benötigen 5% der internistischen Patienten ein psychosomatisches Konsil. Neue, komplexe Behandlungsstrategien, wie Transplantationen, Kardioverter-Defibrillatoren, Medikamentenpumpen, erfordern häufig spezifische psychosoziale Interventionen. Ältere Patienten haben Erkrankungen, die zunehmend chronifizieren und komplexer werden. Damit werden Lebensqualität und psychische Komorbidität zu zentralen Outcomevariablen der Volkskrankheiten. Das zweite große Aufgabenfeld internistischer Psychosomatik ist die Untersuchung und die Behandlung psychosomatischer Patienten im engeren Sinne (Essstörungen, Schmerz- und somatoforme Störungen), weil internistische Diagnostik und Therapie erforderlich oder die Motivation der Patienten primär somatisch ist. Organisationsmodelle reichen von Konsil-/Liaisondiensten bis zu integrierten psychosomatischen Abteilungen oder Fachabteilungen an Allgemeinkrankenhäusern. Aussichtsreiche Forschungsstrategien werden neben der Erforschung psychosomatischer Mechanismen in der Entwicklung pragmatischer Behandlungsprogramme, ihrer Überprüfung in klinischen Studien und der Versorgungsforschung gesehen. Darüber hinaus sollte eine Intensivierung nationaler und internationaler Forschungsnetze erfolgen, wenn immer möglich unter Beteiligung anderer Disziplinen, um auch im Bereich der Forschung konkurrenzfähig zu bleiben.     

The attentional blink is susceptible to concurrent perceptual processing demands

In a rapid serial visual presentation stream processing of a first target (T1) impairs detection or identification of a second target (T2) that appears within 500 ms after T1. This effect characterizes the so-called attentional blink (AB). To evaluate contemporary information-processing accounts of the AB phenomenon in terms of the underlying processing mechanisms the present study examined the potential influence of Task 1 difficulty on the AB effect. To this end, T1 contrast and T1 response requirements were systematically varied across four experiments. Experiment 1 ruled out a mere sensory basis of the contrast manipulation on T2 performance. When only T2 had to be reported (Experiment 2) an AB effect occurred that was slightly modulated by T1 contrast. When report of both T1 and T2 was required in a standard AB task (Experiment 3), the magnitude of the AB depended to a larger extent on stimulus contrast, and it increased further when speeded T1 choice responses were additionally required (Experiment 4). On the basis of the present impact of Task 1 difficulty on the AB effect we conclude that processing limitations cause the AB phenomenon. We discuss such limitations in terms of perceptual (T1 consolidation) and central (response selection) bottleneck processes.     

Training propositional reasoning

Two experiments compared the effects of four training conditions on propositional reasoning. A syntactic training demonstrated formal derivations, in an abstract semantic training the standard truth-table definitions of logical connectives were explained, and a domain-specific semantic training provided thematic contexts for the premises of the reasoning task. In a control training, an inductive reasoning task was practised. In line with the account by mental models, both kinds of semantic training were significantly more effective than the control and the syntactic training, whereas there were no significant differences between the control and the syntactic training, nor between the two kinds of semantic training. Experiment 2 replicated this pattern of effects using a different set of syntactic and domain-specific training conditions.