Academic journal article Attention, Perception and Psychophysics

A Robust Asymmetry in Loudness between Rising- and Falling-Intensity Tones

Academic journal article Attention, Perception and Psychophysics

A Robust Asymmetry in Loudness between Rising- and Falling-Intensity Tones

Article excerpt

Published online: 23 January 2015

© The Psychonomic Society, Inc. 2015

Abstract Tones rising in intensity over a few seconds are perceived as louder than symmetrical tones falling in intensity. However, the causes for such perceptual asymmetry, as well as its magnitude and dependency on contextual and methodological factors remain unclear. In this paper, two psychophysical experiments were conducted to measure the magnitude of this asymmetry for 2-s, 15-dB intensity-varying tones in different conditions. In the first experiment, participants assessed the global loudness of rising- and falling-intensity sounds with an absolute magnitude estimation procedure (AME); in the second experiment, they compared sounds relatively in an adaptive, two-interval, two-alternative forced-choice task (2I-2AFC). In both experiments, the region of intensity change, the design of experimental blocks, and the type of comparison stimulus were systematically manipulated to test for contextual and methodological factors. Remarkably, the asymmetry was virtually unaffected by the different contexts of presentation and similar results with 2I-2AFC and AME measurements were obtained. In addition, the size of the effect was comparable over all but the highest intensity regions (80-90 dB SPL), at which it was significantly smaller. All together, these results indicate that the loudness asymmetry is preserved under different measurement methods and contexts, and suggest that the underlying mechanism is strong and robust. In short, falling tones have to be about 4 dB higher in level than symmetrically rising tones in order to be perceived with the same global loudness, a finding that is still not predicted by current loudness models.

Keywords Temporal processing . Psychoacoustics . Hearing

Introduction

While most psychoacoustical research has been primarily concerned with the perception of stationary signals, a number of studies in the past decade have started investigating more complex, time-varying stimuli (e.g., Chi, Ru, & Shamma, 2005; Lu, Liang, & Wang, 2001; Neuhoff, 1998; Oberfeld, Heeren, Rennies, & Verhey, 2012). Undoubtedly, time variation is essential to completely understand the perception of environmental or musical sounds, for which spectral and energetic characteristics constantly change over time. Processing such changes involves particular attentional and cognitive mechanisms, and recruit specific neural circuits. As pointed out recently by Schutz and Vaisberg (2014), although too often neglected in the past, a sound's temporal shape plays a crucial role in its perception. In particular, perceptual differences in loudness, timbre, or perceived duration have been observed between tones that have identical energy and long-term spectrum, but opposite temporal profiles. Because they occur between temporally asymmetric stimuli - the term "temporal asymmetry" (Patterson, 1994) was used to describe the sounds with different attack and decay times - these arising perceptual differences were often referred to as perceptual "asymmetries" (e.g. see Grassi & Pavan, 2012; Meunier, Vannier, Chatron, & Susini, 2014; Ries, Schlauch, & DiGiovanni, 2008; Susini, McAdams, & Smith, 2007). As a result, this term will also be used throughout the rest of this paper.

The present work is specifically concerned with asymmetries in global loudness. Listeners asked to make global loudness judgments of rising- and falling-intensity sounds of a few seconds, i.e. "to evaluate the overall loudness of the sound over its entire duration," give greater estimates to rising sounds compared to their time-reversed versions, falling sounds (Ponsot, Susini, Saint Pierre, & Meunier, 2013;Susini et al., 2007). The causes and mechanisms underlying these asymmetries remain unclear.

Most previous studies on auditory perceptual asymmetries have relied on short sounds (from 10-250 ms) with temporally asymmetric amplitude envelopes. …

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