Robust and efficient online auditory psychophysics

Abstract

Most human auditory psychophysics research has been conducted with extreme 'auditory hygiene' in carefully controlled environments, with calibrated audio equipment, and potentially hours of repetitive testing with expert, well-characterized listeners. The incompatibility of web-based platforms with such experimental regimes would seem to preclude online auditory psychophysical paradigms, where success may hinge on absolute sound presentation level, reliably estimated perceptual thresholds, and sustained motivation, attention, and vigilance. Here, we introduce and validate a set of procedures that aim to address these challenges and facilitate successful online auditory psychophysics research. First, we establish a simple means of setting sound presentation levels where online participants serve as their own sound level meter. Across a set of three experiments conducted in person, we demonstrate the stability and robustness of this volume setting procedure both 'in the wild' and in controlled settings. Second, we test participants' tone-in-noise thresholds using widely adopted online experiment platforms, and demonstrate that reliable threshold estimates can be derived in approximately one minute of testing. Third, using these sound level setting and thresholding procedures to establish participant-specific stimulus conditions, we show that frequency-selective attention can be reliably demonstrated in individual participants with an online implementation of the classic, yet challenging, probe signal psychophysics paradigm. Finally, we show how threshold and attentional measures relate to well-validated assays of online participant fatigue, task confidence, and apathy acquired at multiple timepoints across the task. In all, this demonstrates the promise of asking new questions in auditory neuroscience with classic, yet challenging, online psychophysics paradigms. The code to duplicate our results is publicly available in JavaScript, through both Pavlovia (pavlovia.org) and Gorilla (gorilla.sc).