Stimulus fluctuations hurt gap detection but aid speech perception elsewhere

Evidence

Fluctuations in the stimulus are associated with poorer gap detection thresholds. This result indicates that the ear represents these fluctuations and may use these fluctuations to benefit perception. An example is the fluctuating masker benefit, in which the ear is able to “listen” in low-frequency temporal epochs to improve speech understanding and detection abilities. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 993

Categorization

• XREF: Fluctuating masker benefit and listening-in-the-dips connects to the listener’s stated interest in normal vs. impaired hearing differences in noise.
• QUESTION: How exactly does the ear ‘listen in’ the low-amplitude temporal epochs, and why does this benefit speech but worsen gap detection?