Biomedical subjects

Rainer Guski

Publications and source records attributed to Rainer Guski.

5 recordsLinked to original sources

PubMed2004

Auditory-visual temporal integration as a function of distance: no compensation for sound-transmission time in human perception.

In a psychophysical outdoor experiment with human subjects, the point of subjective simultaneity (PSS) of auditory and visual stimuli was measured for distances from 1 to 50 m. Repetitive sound and light pulses were presented with various stimulus-onset asynchronies, and subjects judged which modality came first. With increasing distance of the stimuli the PSS shifted in a linear relation toward delays of the light behind the sound. The slope of the regression line (3 ms/m) almost exactly corresponded to that of the temporal disparities resulting from the lower velocity of sound compared to light. These data refute the hypothesis proposed recently that there could be an 'implicit estimation' of sound-arrival time. The brain seems to eliminate such crossmodal temporal disparities by the integration of auditory and visual stimuli that fall into a time window, but not by specific compensatory processes that use an estimate of the sound delay.

Acoustic Stimulation↗

PubMed2004

Representational momentum in spatial hearing.

The final position of a moving visual object usually appears to be displaced in the direction of motion. We investigated this phenomenon, termed representational momentum, in the auditory modality. In a dark anechoic environment, an acoustic target (continuous noise or noise pulses) moved from left to right or from right to left along the frontal horizontal plane. Listeners judged the final position of the target using a hand pointer. Target velocity was 8 degrees s(-1) or 16 degrees s(-1). Generally, the final target positions were localised as displaced in the direction of motion. With presentation of continuous noise, target velocity had a strong influence on mean displacement: displacements were stronger with lower velocity. No influence of sound velocity on displacement was found with motion of pulsed noise. Although these findings suggest that the underlying mechanisms may be different in the auditory and visual modality, the occurrence of displacements indicates that representational-momentum-like effects are not restricted to the visual modality, but may reflect a general phenomenon with judgments of dynamic events.

Acoustic Stimulation↗

PubMed2003

Cross-modal perceptual integration of spatially and temporally disparate auditory and visual stimuli.

Under certain conditions, auditory and visual information are integrated into a single unified percept even when they originate in different locations in space. The present study shows how this illusion, known as the ventriloquism effect, depends on spatial, temporal and cognitive factors. A method of psychophysical scaling was employed in combination with simple auditory-visual stimuli (tone bursts and flashing light spots) that were presented with various spatiotemporal disparities. Participants either judged their impression of the likelihood of a common cause (Experiment 1) or spatial alignment (Experiment 2) or synchrony of sound and light (Experiment 3). In all three experiments the participants' judgements depended significantly on temporal disparity whereas influences of spatial disparity were significant in Experiments 1 and 2. Optimum scores were always obtained when auditory stimuli were presented with a delay of 50-100 ms after the visual stimuli. These results demonstrate that both temporal and spatial proximity of the two stimuli are critical for the experience of phenomenal causality. On the other hand, spatio-temporal ranges for optimal perception of phenomenal causality in Experiment 1 were significantly larger than predicted by simultaneous detection of spatial and temporal disparities. This finding suggests that auditory-visual binding was further facilitated by additional, cognitive, factors, associated with the specific instruction to judge the likelihood of a common cause. Obviously, these instructional influences may reflect similar perceptual effects, as have been shown previously by increasing the complexity or cognitive compellingness of auditory-visual stimuli.

Acoustic Stimulation↗

PubMed2003

Audiovisual phenomenal causality.

We report three experiments in which visual or audiovisual displays depicted a surface (target) set into motion shortly after one or more events occurred. A visual motion was used as an initial event, followed directly either by the target motion or by one of three marker events: a collision sound, a blink of the target stimulus, or the blink together with the sound. The delay between the initial event and the onset of the target motion was varied systematically. The subjects had to rate the degree of perceived causality between these events. The results of the first experiment showed a systematic decline of causality judgments with an increasing time delay. Causality judgments increased when additional auditory or visual information marked the onset of the target motion. Visual blinks of the target and auditory clacks produced similar causality judgments. The second experiment tested several models of audiovisual causal processing by varying the position of the sound within the visual delay period. No systematic effect of the sound position occurred. The third experiment showed a subjective shortening of delays filled by a clack sound, as compared with unfilled delays. However, this shortening cannot fully explain the increased tolerance for delays containing the clack sound. Taken together, the results are consistent with the interpretation that the main source of the causality judgments in our experiments is the impression of a plausible unitary event and that perfect synchrony is not necessary in this case.

Adult↗

PubMed1999

Personal and social variables as co-determinants of noise annoyance.

This paper starts with the fact that noise annoyance is partly due to acoustic factors, partly due to so-called moderating variables, i.e. personal and social aspects of the residents. Noise annoyance is considered to be the (long-term) negative evaluation of living conditions with respect to noise. This evaluation is not simply dependent on past disturbances, but on attitudes and expectations, too. The personal factors influencing the evaluation and described here are: Sensitivity to noise, fear of harm connected with the source, personal evaluation of the source, and coping capacity with respect to noise. The social factors described here are: General (social) evaluation of the source, trust or misfeasance with source authorities, history of noise exposure, and expectations of residents. For most of these variables, data from different community studies are used in order to illustrate the respective moderating effect on annoyance. In addition, some of the moderators are presented as possible tools in order to reduce noise annoyance. It is expected that a significant decrease in a negatively moderating variable is as effective in reducing noise annoyance, as is a significant decrease in noise level.

Journal Article↗