Department of Speech and Hearing Science, University of Illinois Urbana-Champaign, Champaign, Illinois 61822, USA.
Neuroscience Program, University of Illinois Urbana-Champaign, Champaign, Illinois 61822, USA.
J Acoust Soc Am. 2024 Aug 1;156(2):763-773. doi: 10.1121/10.0028119.
The perception of a talker's head orientation is an ecologically relevant task. Humans are able to discriminate changes in talker head orientation using acoustic cues. Factors that may influence measures of this ability have not been well characterized. Here, we examined the minimum audible change in head orientation cues (MACHO) using diotic stimuli. The effects of several factors were tested: talker and gender, stimulus bandwidth (full-band vs low-pass filtered at 8 or 10 kHz), transducer (loudspeaker vs headphone), stimulus uncertainty (interleaved vs blocked presentation of four talkers), and vocal production mode (speech vs singing). The best performance of ∼41° was achieved for full-band, blocked presentation of speech over a loudspeaker. Greater stimulus uncertainty (interleaved presentation) worsened the MACHO by 26%. Bandlimiting at 8 and 10 kHz worsened performance by an additional 22% and 14%, respectively. At equivalent overall sound levels, performance was better for speech than for singing. There was some limited evidence for the transducer influencing the MACHO. These findings suggest the MACHO relies on multiple factors manipulated here. One of the largest, consistent effects was that of talker, suggesting head orientation cues are highly dependent on individual talker characteristics. This may be due to individual variability in speech directivity patterns.
感知说话者的头部方向是一项与生态相关的任务。人类能够通过听觉线索来辨别说话者头部方向的变化。影响这种能力衡量的因素尚未得到很好的描述。在这里，我们使用立体声刺激来检查头部方向线索的最小可听变化（MACHO）。测试了几个因素的影响：说话者和性别、刺激带宽（全带宽与 8 或 10 kHz 的低通滤波）、换能器（扬声器与耳机）、刺激不确定性（四个说话者交错呈现与阻塞呈现）以及发声模式（说话与唱歌）。在扬声器上以全带宽、阻塞方式呈现语音时，最佳表现为约 41°。更大的刺激不确定性（交错呈现）使 MACHO 恶化 26%。8 kHz 和 10 kHz 的带限分别使性能恶化 22%和 14%。在等效的总声级下，语音的表现优于唱歌。有一些有限的证据表明换能器会影响 MACHO。这些发现表明 MACHO 依赖于这里所操纵的多个因素。其中最大的、一致的影响因素是说话者，这表明头部方向线索高度依赖于说话者的个体特征。这可能是由于言语指向性模式的个体差异所致。
