Asymmetric Performance during Discrimination of Sound Motion Directions in Dichotic Stimulation Conditions

• Published in: Human physiology 2021-09, Vol.47 (5), p.506-515
• Main Authors: Semenova, V. V., Petropavlovskaia, E. A., Shestopalova, L. B., Vaitulevich, S. Ph
• Format: Article
• Language: English
• Subjects: Asymmetry; Biomedical and Life Sciences; Biomedicine; Handedness; Human Physiology; Life Sciences; Timing
• ISSN: 0362-1197; 1608-3164
• DOI: 10.1134/S036211972105011X

The study focused on the left–right asymmetry in discriminating moving sound stimuli in dichotic conditions. Healthy adult right-handed participants discriminated the left and right directions of sound motion. A sound stimulus consisted of two parts, a stationary sound at the head midline was followed by a moving sound of a variable duration, which shifted leftward or rightward from the midline. Seven velocities of motion (from 80 to 480 deg/s) were produced by linear changes of interaural time differences (ITDs). The shift was varied from well distinguishable to vanishing values, and the duration of the moving part was decreased in proportion. Hit rates and mean reaction times were measured separately in each of the conditions. As the task complexity increased due to decreasing sound shifts in shorter time, the percentage of rightward responses became higher than that of leftward responses. However, the total amount of leftward responses contained a larger portion of hits. This asymmetry in performance showed no correlation with the consistency of hand preference.