Offering a highly integrated and comprehensive coverage of the field, this book is suitable as a core textbook in advanced courses dealing with the role of ...

A perfectly matched layer (PML) absorbing material composed of a uniaxial anisotropic material is presented for the truncation of finite-difference time-domain (FDTD) lattices. It is shown that the uniaxial PML material formulation is mathematically equivalent to the perfectly matched layer method published by Berenger (see J. Computat. Phys., Oct. 1994). However, unlike Berenger's technique, the uniaxial PML absorbing medium presented in this paper is based on a Maxwellian formulation. Numerical examples demonstrate that the FDTD implementation of the uniaxial PML medium (...) is stable, equal in effectiveness as compared to Berenger's PML medium, while being more computationally efficient. (shrink)

Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing. On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning. On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account (...) for the goal-directedness of even the simplest reaction in an experimental task. We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference. Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes. We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data. Key Words: action planning; binding; common coding; event coding; feature integration; perception; perception-action interface. (shrink)

In this paper, we introduce anaffective variant of the Simon paradigm. Three experiments are reported in which nouns and adjectives with a positive, negative, or neutral affective meaning were used as stimuli. Depending on the grammatical category of the presented word (i.e. noun or adjective), participants had to respond as fast as possible by saying a predetermined positive or negative word. In Experiments 1 and 2, the words POSITIVE and NEGATIVE were required as responses, in Experiment 3, FLOWER and CANCER (...) were used as response words. Despite the fact that participants were explicitly instructed to ignore the affective meaning of the presented words, reaction times were faster when the affective connotation of the presented word and the correct response was the same than when it differed. The results lendfurther support tothe hypothesis that stimulus valence can be processed automatically. We also argue that the affective Simon paradigm can be used as a flexible tool for the study of affective-processing and discuss how other variants of the Simon paradigm can be developed to stimulate research on other aspects of information-processing. (shrink)

Viewing emotion from an evolutionary perspective, researchers have argued that simple responses to affective stimuli can be triggered without mediation of cognitive processes. Indeed, findings suggest that positively and negatively valenced stimuli trigger approach and avoidance movements automatically. However, affective stimulus–response compatibility phenomena share so many central characteristics with nonaffective stimulus–response compatibility phenomena that one may doubt whether the underlying mechanisms differ. We suggest an “affectively enriched” version of the theory of event coding (TEC) that is able to account for (...) both affective and nonaffective compatibility, and that can account for the observation that both types of compatibility seem to be modulated by goals and intentions. Predictions from the model are tested in an experiment where participants carried out approach and avoidance responses to either the valence or the orientation of emotionally charged pictures. Under affective instruction the positive-approach/negative-avoid mapping yielded faster responses than the positive-avoid/negative-approach mapping, but no such effect was observed under spatial instruction. Conversely, spatial compatibility effects were obtained under spatial, but not under affective instruction. We conclude that affective and nonaffective compatibility effects reflect the same mechanism. (shrink)