Consciousness and control in task switching

Participants were required to switch among randomly ordered tasks, and instructional cues were used to indicate which task to execute. In Experiments 1 and 2, the participants indicated their readiness for the task switch before they received the target stimulus; thus, each trial was associated with two primary dependent measures: (1) readiness time and (2) target reaction time. Slow readiness responses and instructions emphasizing high readiness were paradoxically accompanied by slow target reaction time. Moreover, the effect of task switching on readiness time was an order of magnitude smaller then the (objectively estimated) duration required for task preparation (Experiment 3). The results strongly suggest that participants have little conscious awareness of their preparedness and challenge commonly accepted assumptions concerning the role of consciousness in cognitive control.     

Control of stimulus-response translation in dual-task performance

In contradiction to stimulus-response- (S-R-) translation bottleneck models of dual-task control, stimulus processing in a primary task is affected by its compatibility with the response in a secondary, later performed task (Hommel, 1998a)- an indication of parallel S-R translation. Here we show that this backward-compatibility effect is independent of working-memory load, whether this is induced by an extra memory task (Experiment 1) or by increasing the number of S-R alternatives in the primary task (Experiment 2). However, backward effects occur even when the secondary task is no longer carried out (Experiment 3) and they are strongly affected by the inconsistency of previously used S-R mappings (Experiment 4). These findings suggest that S-R translation is (or can be) capacity-independent and automatic even under multiple-task conditions, and that it is mediated by direct S-R associations that emerge after only little practice.     

Perception in action: multiple roles of sensory information in action control

Perceptual processes play a central role in the planning and control of human voluntary action. Indeed, planning an action is a sensorimotor process operating on sensorimotor units, a process that is based on anticipations of perceptual action effects. I discuss how the underlying sensorimotor units emerge, and how they can be employed to tailor action plans to the goals at hand. I also discuss how even a single action can induce sensorimotor binding, how intentionally implemented short-term associations between stimuli and responses become autonomous, how feature overlap between stimulus events and actions makes them compatible, and why action plans are necessarily incomplete.

Zur Problematik der Suchtgefährdung von berufstätigen Medizinern

Two samples of working physicians have been compared in a cross-sectional study – one representative sample of addicted physicians with a substance abuse problem (n=142) and one representative sample (n=275) of physicians in general; the objective was to develop preventive strategies. As a measuring instrument a specific questionnaire on quality of life of physicians (Reimer and Jurkat) has been used. Generally, quality of life is lower in the substance abuse sample in comparison to the control group. It can be concluded that the variables concerning the areas life satisfaction/-dissatisfaction and health differentiate even more between the groups than the areas work satisfaction/-dissatisfaction and choice of occupation. Whereas quality of life of female physicians was on the average somewhat higher than that of their male colleagues in the control group, this could not be confirmed in the sample of impaired physicians. Especially the ability to relax seems to be essential as a preventive measure, and apparently it is of high importance for working physicians to care for an adequate and satisfying private life to balance their stressful working life.     

A Simon effect induced by induced motion and location: Evidence for a direct linkage of cognitive and motor maps

It has been argued that two distinct maps of visual space are formed: a cognitive map that is susceptible to illusions, and a motor map that represents the physical world veridically. In the present study, subjects responded to a nonspatial attribute of a visual target stimulus by pressing a left or right key, while an illusory horizontal displacement of the target was induced. A Simon-type effect was obtained to the induced target motion or position shift—that is, responses were faster when the illusory target motion or location corresponded to the response position. Further experiments indicated that the observed effects cannot be accounted for by attentional shifts. These results suggest that the content of the cognitive map does not only influence perceptual judgments but is also responsible for the automatic activation of response codes. In other words, perception and action seem to be fed by a common, cognitively penetrable, spatial representation.     

Intentional control of attention: action planning primes action-related stimulus dimensions

Neurophysiological observations suggest that attending to a particular perceptual dimension, such as location or shape, engages dimension-related action, such as reaching and prehension networks. Here we reversed the perspective and hypothesized that activating action systems may prime the processing of stimuli defined on perceptual dimensions related to these actions. Subjects prepared for a reaching or grasping action and, before carrying it out, were presented with location- or size-defined stimulus events. As predicted, performance on the stimulus event varied with action preparation: planning a reaching action facilitated detecting deviants in location sequences whereas planning a grasping action facilitated detecting deviants in size sequences. These findings support the theory of event coding, which claims that perceptual codes and action plans share a common representational medium, which presumably involves the human premotor cortex.