Individual particularities of examinees at lateralization of stationary and moving sound images (virtual reality: specific manifestations)

Abstract

Characteristics of subjective auditory space at lateralization of stationary and moving fused sound images (FSI) were studied in 15 examinees. The method of dichotic stimulation with a series of binaurally presented click trains was used, at varying of interaural intensity differences (ΔI) within the limits of ±13 dB. Duration of the click series amounted to 2 s. To establish perception of moving FSI, the value of interaural differences in stimulation time (ΔT ) varied from ±630 µs to zero throughout the time of the sound signal action. Under conditions of stationary and moving FSI we estimated expansion of the subjective auditory space (as the distance between the extreme left and extreme right points of FSI position, %), the site of FSI position in it (% related to the head midline), the rate of FSI moving (deg/s), and variability measured by σ value of examinees’ estimates of position of both stationary and moving FSI at the initial and final moments of moving. It was established that under conditions of stationary FSI, at the under border ΔI values (from −13 to 13 dB), expansion of auditory space varied from 50 to 149 degrees. Variability of estimations of the stationary FSI position at ΔI = ±13 dB also differed in various examinees, at σ values from 3–4 to 17–20 deg. Under conditions of moving FSI, expansion of the subjective auditory space increased to amount to from 107 to 185 deg within the borders of ΔI = ±13 dB, whereas σ value was even somewhat decreased and amounted to from 2–3 to 12–16 deg. The rate of FSI moving at the same ΔI varied in different examinees from 13 to 43 deg/s. The diversity of quantitative characteristics of the subjective auditory space among the examinees is considered from the point of view of individual differences in structure of the auditory space and of the level of physiological noises in the brain centers responsible for making a particular decision. It is suggested that the presented limits of individual examinees’ differences might be of essential importance for preparation of operators to corresponding kinds of work.