Referenzsemantik in der Partnermodellierung

How can we explain that an assertion on something perceived can be understood in the same manner by somebody who cannot perceive that scene? This problem bases the interest in computational linguistics in how listener modeling could possibly be harmonized with reference semantics. Mental images substituting real perception appear as a way out. The architecture of the listener model has to be adapted to the creation and use of such pictorial data structures. Furthermore, the relation between the latter and a verbal (i. e., propositional) representation must be understood. The resulting architecture of a listener model with reference semantics can be employed to solve communicational problems from three general classes in a better way, as is demonstrated by an example implementation.     

The relationship between locus of control and long-term stuttering treatment outcome in adult stutterers

The present study was designed to investigate the extent to which adult stutterers' scores on the Locus of Control of Behaviour (LCB) scale are predictive of their ability to maintain speech fluency immediately following intensive treatment and approximately 2 years later. Twenty-one subjects participated in a 3-week intensive treatment program based on the Precision Fluency Shaping Program. Thirteen subjects could be contacted again 2 years later to participate in a follow-up evaluation. While most subjects showed a significant long-term improvement in fluency, no predictive relationship was found between scores on the LCB scale and the level of fluency, measured in percentage of words stuttered, post-treatment or at follow-up. However, LCB scores were found to be predictive of the subjects' fluency self-evaluation measured post-treatment and at follow-up. Overall, the present study suggests that while the LCB scale may contribute to the prediction of long-term treatment outcome, particularly as perceived by the client, other client and process variables will need to be considered as well.     

Effects of task instructions and oscillation frequency on bimanual coordination

Increases in the oscillation frequency of bimanual movements produce a switch from an anti-phase (180° relative phase) to an in-phase (0° relative phase) coordination pattern. This finding is observed when subjects are instructed not to intervene when they feel themselves slipping out of the anti-phase pattern. The question addressed in this study concerned how performance would be affected if subjects were instructed to try to maintain the pattern at all times. This issue was addressed using two separate groups of subjects: one group was given the do not intervene instructions, the other group was told to try to stay with the pattern at all times. Forearm rotations were tested in 15 s trials, paced by an auditory metronome set at 1.0, 1.5, 2.0, 2.5, and 3.0 Hz. Frequency distributions of the point estimates of relative phase were analyzed. The Do not Intervene group replicated previous findings, as indicated by the development of a bimodal histogram of relative phase distributions with increases in oscillation frequency. However, a very different pattern of findings emerged with increases in oscillation frequency for the group told to stay with the anti-phase pattern. Rather than a bimodal distribution being developed, the data maintained 180° as its central tendency — no secondary distribution developed around 0° relative phase. These data suggest that volitional control can over-ride the inherent dynamical tendencies of the motor system.     

THE VISUAL SYSTEM'S MEASUREMENT OF INVARIANTS NEED NOT ITSELF BE INVARIANT

Abstract— When two shapes that differ in orientation or size have to be compared or objects have to be recognized from different viewpoints, the response time and error rate art systematically affected by the size of the geometric difference. In this report, we argue that these effects are not necessarily solid evidence for the use of mental transformations and against the use of invariants by the visual system. We report an experiment in which observers were asked to give affine-invariant coordinates of a point located in an affine frame defined by three other points. The angle subtended by the coordinate axes and the ratio of the lengths of their unit vectors systematically affected the measurement errors. This finding demonstrates that the visual system's measurement of invariants need not itself be invariant.     

Stop—reaction time and the internal clock

In astop-reaction-time (stop-RT) task, a subject is presented with a regular, isochronous sequence of brief signals separated by a constant time interval, orstimulus onset asynchrony (SOA). His/her task is to press a response key as fast as possible when the sequence stops. As the sequence unfolds, an internal representation of the SOA duration builds up. Stop-RT is assumed to be triggered when aninternal clock, operating as an “alarm clock,” reaches a time criterion. Criterion setting is contingent upon variability in the SOA’s internal representation. In Experiment 1A, stop-RT was measured for isochronous sequences of brief tones, light flashes, and also sequences of tones and flashes presented in regular alternation (tone-light-tone…). Stop-RT was a linear function of SOA duration (ranging from 250 to 1,000 msec), regardless of modality, supporting a “central-clock” hypothesis. On the other hand, taken together, the results of Experiments 1A, 1B, 2, and 3 suggest that no internal representation of thebimodal (tone-light) SOA of alternating sequences builds up. Indeed, an alternating sequence is physically equivalent to two interlaced isochronous subsequences, one auditory and one visual. So,two internal representations, one for the auditory (tone-tone) and one for the visual (light-light) SOA, could build up, andtwo time criteria running “in parallel” could thus support stop-RT. To provide a critical test of parallel timing, stop-RT was measured for bimodal 5∶3 polyrhythms formed by the superposition of auditory and visual isochronous sequences that haddifferent SOA durations (Experiment 4). Parallel timing accounted for a large proportion of variance in polyrhythmic stop-RT data. Overall findings can be accounted for by assuming a functional architecture of an internal clock in which pulses emitted by acentral pacemaker are available in parallel with twomodality-specific switch-accumulator “timing modules.”