Duration effects on detection cues in simultaneous masking: Analysis using decision variable correlationa)

Experiments involving the detection of a tone presented in noise form the basis of psychophysical estimates of auditory frequency selectivity. These estimates are central to theories of hearing and to models/algorithms for hearing aid fitting, automatic speech recognition, and digital audio compression. Despite widespread application of tone-in-noise experiments, cues used by listeners to detect the tone are debated. This study adopts a molecular psychophysics approach-decision variable correlation-to evaluate whether trial-by-trial responses are consistent with candidate decision variables, including stimulus energy and temporal envelope fluctuations. Detection thresholds were measured in normal-hearing adults for 1000 or 4000 Hz tones presented in one-third octave noise centered on the tone frequency. The tone and noise were gated simultaneously and thresholds were measured for durations of 10, 20, 50, and 100 ms. The reliability of energy-based cues was limited by incorporating a roving-level paradigm. Similarly, the use of short tones limited the reliability of envelope-based cues. Results revealed that listeners adopted a strategy that emphasized energy-based cues for detecting short-duration tones. Conversely, participants relied progressively more on envelope-based cues as tone duration increased. This finding suggests models of human psychophysics may benefit from a decision device that adjusts cue weights based on stimulus duration.