Some factors influencing loudness asymmetries between rising and falling-intensity stimuli

International audiencePrevious research demonstrated that the loudness asymmetry between 1-kHz rising and fallingintensitytones is a robust phenomenon, whose origins still remain unclear. In the present study, this phenomenon wasfurther examined as a function of two stimuli characteristics: the spectral content and the intensity-region. In a firstexperiment, the global loudness of rising and falling-intensity sounds with various spectral contents (pure tones from250 Hz to 8 kHz and broadband noises) presented in different intensity-regions (from [50-65 dB SPL] to [70-85 dBSPL]) was assessed in an absolute magnitude estimation task. Significant asymmetries were found for tones at allfrequencies, but not for broadband noises. In addition, a significant interaction between the stimulus direction and theintensity-region was observed for both tones and noises. This interaction was further examined in a secondexperiment using an adaptive loudness-matching procedure. Although greater asymmetries were again observed fortones, significant asymmetries were found for noises as well. Furthermore, the size of the asymmetries wassignificantly decreased with the intensity-region when the pairs were composed of rising followed by falling stimuli.These results are discussed in the light of recent physiological and neuroscience studies conducted with this type ofstimuli