Temporal weights in loudness: Investigation of the effects of background noise and sound level.

Alexander Fischenich,Jesko Verhey,Jan Hots,Daniel Oberfeld,Darren Rhodes

doi:10.1371/journal.pone.0223075

Alexander Fischenich, Jesko Verhey + Show 3 more

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https://doi.org/10.1371/journal.pone.0223075

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Abstract

Previous research has consistently shown that for sounds varying in intensity over time, the beginning of the sound is of higher importance for the perception of loudness than later parts (primacy effect). However, in all previous studies, the target sounds were presented in quiet, and at a fixed average sound level. In the present study, temporal loudness weights for a time-varying narrowband noise were investigated in the presence of a continuous bandpass-filtered background noise and the average sound levels of the target stimuli were varied across a range of 60 dB. Pronounced primacy effects were observed in all conditions and there were no significant differences between the temporal weights observed in the conditions in quiet and in background noise. Within the conditions in background noise, there was a significant effect of the sound level on the pattern of weights, which was mainly caused by a slight trend for increased weights at the end of the sounds (“recency effect”) in the condition with lower average level. No such effect was observed for the in-quiet conditions. Taken together, the observed primacy effect is largely independent of masking as well as of sound level. Compatible with this conclusion, the observed primacy effects in quiet and in background noise can be well described by an exponential decay function using parameters based on previous studies. Simulations using a model for the partial loudness of time-varying sounds in background noise showed that the model does not predict the observed temporal loudness weights.

Highlights

Loudness is one of the fundamental aspects of auditory sensation and is important when it comes to the perception of our environment through the auditory channel
For the condition in background noise where the mean segment level was 7.5 dB higher than the detection threshold in background noise (BGNSLBGN7.5), the primacy effect was slightly weaker than in the other conditions, and the mean weights on the final three segments were slightly higher than the weights for the middle segment, indicating a recency effect
The condition × segment number interaction was not significant, F(36, 252) = 1.91, ε~ = .449, p = .058, Z2p = .214, which indicates that masking and signal level had no significant effect on the pattern of temporal weights

Summary

Introduction

Loudness is one of the fundamental aspects of auditory sensation and is important when it comes to the perception of our environment through the auditory channel. Static loudness models do not seem to account for all aspects of the loudness of sounds that vary in level across time [5,6]. One reason may be that not all temporal parts of a sound are weighted when listeners judge loudness. Previous studies consistently show that the beginning of a time-varying sound is of higher importance for the perception of loudness than later temporal parts [7,8,9], which has been referred to as a primacy effect (for a review see [10]). In addition to the primacy effect, some studies found higher perceptual weights assigned to the end of the sounds, commonly referred to as a recency effect [8,9]

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