Improving sound discrimination through Gestalt binding of inharmonic frequencies
School/Affiliation:McMaster University, MAPLE lab
Virtual or In-person:In-person
Our ability to detect and discriminate between auditory signals is crucial to our daily lives (Gundy, 1961), and plays a crucial role in auditory warning systems for a variety of safety critical devices (Stanton & Edworthy, 2019) —such as hospital alarms (Sanderson et al., 2006). Recent research has focused on inharmonicity as a salient dimension in signal detection (McPherson et al., 2022). This could simply be a result of involuntary reactions towards dissonant sound. However, we speculate that gestalt binding of frequencies could play a role in its effect. To assess whether this indicates binding of the inharmonic tones or otherwise, we measured accuracy and response time in two-alternative forced choice tasks, whereby participants decided whether a melodic sequence played in noise ascended or descended. The sequence included either congruent, incongruent, or an absence of higher, inharmonic frequencies. We found that the congruent additional harmonics improved mean accuracy and reduced mean response time. The incongruent harmonics reduced response time but also reduced accuracy. The results suggest that additional harmonics consistently speed up reaction time. However, increases in accuracy for the congruent condition relative to the decrease for incongruent implies that discrimination depends on congruency. Without this, additional frequencies may be a source of distraction. Overall, this supports a reactionary rather than a binding mechanism of facilitation. Future experiments will further explore the role of binding in detection by varying amplitude envelope between the signal and higher harmonics.