Woods Kevin J P, Siegel Max H, Traer James, McDermott Josh H
Department of Brain and Cognitive Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
Program in Speech and Hearing Bioscience and Technology, Harvard University, 260 Longwood Ave, Boston, MA, 02115, USA.
Atten Percept Psychophys. 2017 Oct;79(7):2064-2072. doi: 10.3758/s13414-017-1361-2.
Psychophysical experiments conducted remotely over the internet permit data collection from large numbers of participants but sacrifice control over sound presentation and therefore are not widely employed in hearing research. To help standardize online sound presentation, we introduce a brief psychophysical test for determining whether online experiment participants are wearing headphones. Listeners judge which of three pure tones is quietest, with one of the tones presented 180° out of phase across the stereo channels. This task is intended to be easy over headphones but difficult over loudspeakers due to phase-cancellation. We validated the test in the lab by testing listeners known to be wearing headphones or listening over loudspeakers. The screening test was effective and efficient, discriminating between the two modes of listening with a small number of trials. When run online, a bimodal distribution of scores was obtained, suggesting that some participants performed the task over loudspeakers despite instructions to use headphones. The ability to detect and screen out these participants mitigates concerns over sound quality for online experiments, a first step toward opening auditory perceptual research to the possibilities afforded by crowdsourcing.
通过互联网远程进行的心理物理学实验能够从大量参与者那里收集数据，但牺牲了对声音呈现的控制，因此在听力研究中并未得到广泛应用。为了帮助规范在线声音呈现，我们引入了一项简短的心理物理学测试，以确定在线实验参与者是否佩戴了耳机。听众判断三个纯音中哪个最安静，其中一个音在立体声通道上相位相差180°呈现。由于相位抵消，这项任务戴耳机时很容易完成，但通过扬声器则很难。我们在实验室中通过测试已知佩戴耳机或通过扬声器聆听的听众来验证该测试。筛选测试有效且高效，通过少量试验就能区分两种聆听模式。在网上进行测试时，获得了双峰分布的分数，这表明尽管有使用耳机的指示，但仍有一些参与者通过扬声器完成了任务。检测并筛选出这些参与者的能力减轻了人们对在线实验声音质量的担忧，这是朝着将听觉感知研究开放给众包所带来的可能性迈出的第一步。
