Loudness Change in Response to Dynamic Acoustic Intensity

Three experiments investigate psychological, methodological, and domain-specific characteristics of loudness change in response to sounds that continuously increase in intensity (up-ramps), relative to sounds that decrease (down-ramps). Timbre (vowel, violin), layer (monotone, chord), and duration (1.8 s, 3.6 s) were manipulated in Experiment 1. Participants judged global loudness change between pairs of spectrally identical up-ramps and down-ramps. It was hypothesized that loudness change is overestimated in up-ramps, relative to down-ramps, using simple speech and musical stimuli. The hypothesis was supported and the proportion of up-ramp overestimation increased with stimulus duration. Experiment 2 investigated recency and a bias for end-levels by presenting paired dynamic stimuli with equivalent end-levels and steady-state controls. Experiment 3 used single stimulus presentations, removing artifacts associated with paired stimuli. Perceptual overestimation of loudness change is influenced by (1) intensity region of the dynamic stimulus; (2) differences in stimulus end-level; (3) order in which paired items are presented; and (4) duration of each item. When methodological artifacts are controlled, overestimation of loudness change in response to up-ramps remains. The relative influence of cognitive and sensory mechanisms is discussed.