An online headphone screening test based on dichotic pitch

Abstract

Online experimental platforms can be used as an alternative, or complement, to lab-based research. However, when conducting auditory experiments via online methods, the researcher has limited control over the participants’ listening environment. We offer a new method to probe one aspect of that environment, headphone use. Headphones not only provide better control of sound presentation but can also “shield” the listener from background noise. Here we present a rapid (< 3 minute) headphone screening test based on Huggins Pitch (HP), a perceptual phenomenon that can only be detected when stimuli are presented dichotically. We validate this test using a cohort of “Trusted” online participants who completed the test using both headphones and loudspeakers. The same participants also trialled a widely used headphone test (AP test; Woods et al., 2017). We demonstrate that compared to the AP test, the HP test has a higher selectively for headphone users, rendering it as a compelling alternative to the existing screening method. Overall, the new HP test correctly detects 80% of headphone users and has a false positive rate of 20%. Moreover, we demonstrate that there is little overlap between participants who pass both HP and AP tests over loudspeakers. Therefore, combining the two tests can lower the false positive rate to ~7% (but at the expense of an increased false negative rate). This should be useful in situations where headphone use is particularly critical (e.g. dichotic or spatial manipulations). An implementation of the new test is available with JavaScript and through Gorilla (gorilla.sc).

Reliability of web-based affective auditory stimulus presentation

“…As such, loudspeaker systems that broadcast a single channel/output of the combined audio could contribute to false positives. For future studies, recent developments of alternative headphone tests may help to resolve this issue (Milne et al, 2020). Despite the limitations, our findings show that affective responses are robust and can be evoked online to a level comparable with those collected in more controlled, in-lab environments.…”

“…While the former issue is difficult to overcome, ensuring that participants wear headphones (including in-ear varieties, i.e., earphones) can help to increase sound quality and reduce interfering noises from the surrounding environment. Recently, headphone screening tests have been developed and validated online (Milne et al, 2020; Woods et al, 2017), allowing an increase web-based audio presentation quality.…”

Reward enhances online participants’ engagement with a demanding auditory task

“…With the blooming of online experiments, it is important to understand how we can improve the quality of data obtained in remote auditory assessments (Leensen, De Laat, Snik, & Dreschler, 2011; Milne et al, 2020; Slote & Strand, 2016). Our finding that reward increased the proportion of participants who achieved low SRTs demonstrates that participant attention, motivation and commitment are important factors to consider when auditory tests involving effortful listening are conducted online.…”

“…Otherwise, the same stimuli and test heuristics were used as in the in-lab settings. To make sure that participants were wearing headphones, they were screened for headphone use with the approach introduced by Milne et al (2020). A strict version of the screening task, demonstrated to yield a 7% false positive rate, was used.…”

Recall of Speech is Impaired by Subsequent Masking Noise: A Direct Replication of Rabbitt (1968)

“…They first completed a browser sound check (Milne et al, 2020) to ensure they could hear presented audio and were then instructed to adjust their audio to a comfortable volume and to not change it during the experiment. Next, participants completed a headphone screening (Milne et al, 2020) that required them to listen to three brief stimuli and identify which of the three contained a Huggins' Pitch (one white noise signal presented in each ear which, when combined, produce the perception of hearing a tone). These pitches can only be perceived when headphones are used in both ears, and are weak or absent when played over loudspeakers.…”