Cues for tone-in-noise detection: Evidence from constant-stimuli and adaptive approaches

Although tone-in-noise (TIN) detection has been studied for nearly a century, controversy still exists regarding the cues listeners use to detect the tone. This study investigated TIN detection in conditions that limited access to either level or temporal cues. Young normal-hearing listeners (N = 24) were tasked with detecting a 2-kHz tone in a simultaneously gated noise that was either narrowband [60 Hz wide, 50 dB sound pressure level (SPL), centered around 2 kHz] or broadband threshold-equalizing noise (125-15 000 Hz, 50 dB SPL/equivalent rectangular bandwidth). For both bandwidths, access to level cues was limited by rescaling portions of the magnitude spectrum, and access to temporal cues was limited by replacing the tone signal with a noise signal. As an adaptive procedure may allow listeners to learn different cues within each run, listeners were also tested using a constant-stimuli procedure, where performance was measured without feedback for randomly interspersed trials involving primarily level cues, primarily temporal cues, or both. The results suggest that both types of cues play a role in classic TIN detection, with level cues playing a greater role in narrowband conditions. Thresholds in the adaptive-procedure conditions were correlated with performance in the constant-stimuli conditions, suggesting consistent individual differences in the weighting of the two cues.