Short-term cognitive fatigue of spatial selective attention after face-to-face conversations in virtual noisy environments

Spatial selective attention is an important asset for communication in cocktail party situations but may be compromised by short-term cognitive fatigue. Here we tested whether an effortful conversation in a highly ecological setting depletes task performance in an auditory spatial selective attention task. Young participants with normal hearing performed the task before and after (1) having a real dyadic face-to-face conversation on a free topic in a virtual reverberant room with simulated interfering conversations and background babble noise at 72 dB SPL for 30 minutes, (2) passively listening to the interfering conversations and babble noise, or (3) having the conversation in quiet. Self-reported perceived effort and fatigue increased after conversations in noise and passive listening relative to the reports after conversations in quiet. In contrast to our expectations, response times in the attention task decreased, rather than increased, after conversation in noise and accuracy did not change systematically in any of the conditions on the group level. Unexpectedly, we observed strong training effects between the individual sessions in our within-subject design even after one hour of training on a different day.

Communication conditions in virtual acoustic scenes in an underground station

Underground stations are a common communication situation in towns: we talk with friends or colleagues, listen to announcements or shop for titbits while background noise and reverberation are challenging communication. Here, we perform an acoustical analysis of two communication scenes in an underground station in Munich and test speech intelligibility. The acoustical conditions were measured in the station and are compared to simulations in the real-time Simulated Open Field Environment (rtSOFE). We compare binaural room impulse responses measured with an artificial head in the station to modeled impulse responses for free-field auralization via 60 loudspeakers in the rtSOFE. We used the image source method to model early reflections and a set of multi-microphone recordings to model late reverberation. The first communication scene consists of 12 equidistant (1.6 m) horizontally spaced source positions around a listener, simulating different direction-dependent spatial unmasking conditions. The second scene mimics an approaching speaker across six radially spaced source positions (from 1 m to 10 m) with varying direct sound level and thus direct-to-reverberant energy. The acoustic parameters of the underground station show a moderate amount of reverberation (T30 in octave bands was between 2.3 s and 0.6 s and early-decay times between 1.46 s and 0.46 s). The binaural and energetic parameters of the auralization were in a close match to the measurement. Measured speech reception thresholds were within the error of the speech test, letting us to conclude that the auralized simulation reproduces acoustic and perceptually relevant parameters for speech intelligibility with high accuracy.