Answer Sets and Qualitative Decision Making

Logic programs under answer set semantics have become popular as a knowledge representation formalism in Artificial Intelligence. In this paper we investigate the possibility of using answer sets for qualitative decision making. Our approach is based on an extension of the formalism, called logic programs with ordered disjunction (LPODs). These programs contain a new connective called ordered disjunction. The new connective allows us to represent alternative, ranked options for problem solutions in the heads of rules: A × B intuitively means: if possible A, but if A is not possible then at least B. The semantics of logic programs with ordered disjunction is based on a preference relation on answer sets. We show that LPODs can serve as a basis for qualitative decision making.     

Coordination of a discrete response with periodic finger tapping: additional experimental aspects for a subtle mechanism

The authors investigated the coordination of periodic right-hand tapping with single stimulus-evoked discrete lefthand taps to check for task interactions and a possible relationship between phase resetting (see tapping literature; e.g., J. Yamanishi, M. Kawato, & R. Suzuki, 1979) and phase entrainment (see tremor literature; e.g., R. J. Elble, C. Higgins, & L. Hughes, 1994). The experimental paradigm employs a dual-task condition as used by K. Yoshino, K. Takagi, T. Nomura, S. Sato, and M. Tonoike (2002), and it includes normal tapping and isometric tapping with the authors recording finger positions and ground contact forces. Four different types of coordination schemes were observed in tapping behavior: marginal tapping interaction (MTI), periodic tap retardation (PTR), periodic tap hastening (PTH), and discrete tap entrainment (DTE); MTI and PTR correspond to the phase-resetting effect for the coordination of periodic tapping with single discrete taps. The novel aspect of the study described in this article includes the impact of the periodic tapping on the discrete tap timing and the hastening of the periodic tapping due to the discrete tap behaviors resulting in a synchronized execution of the two concurrent tapping tasks. All participants showed a dominant tapping behavior, but they all used the other nondominant forms of the four reported coordination schemes in some trials too, which reflects possible constraints of the sensorimotor system in handling two competing tasks.     

Is it the sound or your relationship to it? The role of acceptance in predicting tinnitus impact

Tinnitus is an experience of sound in the absence of an appropriate external source. A symptom that can accompany most central or peripheral dysfunctions of the auditory system, tinnitus can lead to significant distress, depression, anxiety, and decreases in life quality. This paper investigated the construct of psychological acceptance in a population of tinnitus patients. First, a cross-sectional study (N = 77) was conducted in which a tinnitus specific acceptance questionnaire was developed. Results showed that a Tinnitus Acceptance Questionnaire (TAQ) generated good internal consistency. A factor solution was derived with two factors: activity engagement and tinnitus supression. Second, a longitudinal study (N = 47) investigated the mediating role of acceptance on the relationship between tinnitus distress at baseline and tinnitus distress, anxiety, life quality, and depression at a 7-month follow-up. The results showed full mediation of activity engagement for depression and life quality at follow-up, partial mediation for tinnitus distress, and no mediation for anxiety. The role of acceptance in the negative impact of tinnitus distress merits further investigation.     

The influence of relevant and irrelevant stereoscopic depth cues: Depth information does not always capture attention

Previous research reported ambiguous findings regarding the relationship of visuospatial attention and (stereoscopic) depth information. Some studies indicate that attention can be focused on a distinct depth plane, while other investigations revealed attentional capture from irrelevant items located in other, unattended depth planes. To evaluate whether task relevance of depth information modulates the deployment of attentional resources across depth planes, the additional singleton paradigm was adapted: Singletons defined by depth (i.e., displayed behind or in front of a central depth plane) or color (green against gray) were presented among neutral items and served as targets or (irrelevant) distractors. When participants were instructed to search for a color target, no attentional capture from irrelevant depth distractors was observed. In contrast, it took substantially longer to search for depth targets when an irrelevant distractor was presented simultaneously. Color distractors as well as depth distractors caused attentional capture, independent of the distractors’ relative depth position (i.e., in front of or behind the target). However, slight differences in task performance were obtained depending on whether or not participants fixated within the target depth plane. Thus, the current findings indicate that attentional resources in general are uniformly distributed across different depth planes. Although task relevant depth singletons clearly affect the attentional system, this information might be processed subsequent to other stimulus features.     

Surprising depth cue captures attention in visual search

A substantial amount of evidence indicates that surprising events capture attention. The present study was primarily intended to investigate whether expectancy discrepant depth information also is able to capture attention immediately and—more specifically—whether cues that are relatively closer or farther differentially modulate behavior. For this purpose, participants had to identify one of two target letters in a search display. Stimulus positions were initially cued by uninformative placeholders. After half of the trials, the cue at the target position was suddenly and unexpectedly (critical trial) displayed closer to or farther from the observer. In line with previous research, both depth cues captured attention on their very first appearance. Performance in the critical trial was superior to the error rates in the trials without depth cue and was even above the performance in subsequent trials that included depth cue. This effect was only observed when the cue preceded the target by 400 ms. Using a shorter cue-stimulus interval of 100 ms, only a delayed improvement was observed, which denotes a typical feature of surprise capture. Moreover, response times were faster in trials comprising a depth cue, and this was already true for the critical trial. Apart from that, no other marked differences between near and far depth cues were observed. Therefore, the present results emphasize that surprising depth information indeed captures attention. However, in contrast to other perceptual tasks, search performance was not considerably influenced by relative position in depth.