Decision strategies in loudness judgments of time-varying sounds inferred from two psychophysical tasks
Résumé
Psychophysical reverse-correlation has been shown to provide a unique framework for identifying decision strategies underlying various perceptual evaluations. Over the last few years, this method has been employed to examine specifically temporal weighting of loudness for time-varying sounds. Primacy and recency e↵ects were observed, indicating
that level-variations occurring at the beginning or at the end of non-stationary sounds have a stronger impact on their
global loudness than others, a finding incompatible with the uniform temporal weighting used in current indicators of
loudness such as LAeq or N5. However, such e↵ects have been exclusively observed in discrimination tasks. In this
study, the temporal weighting of loudness was measured and compared with the same group of subjects participating
in (i) level-discrimination tasks and in (ii) magnitude estimation (ME) tasks. Stimuli were 3-s white noises consisting
of 250-ms segments randomly varying in level. The weights attributed to the 12 temporal portions of these sounds
were inferred from subjects ’responses using either multiple (i) logistic or (ii) linear regressions. Small but significant
primacy and recency e↵ects were observed in the level-discrimination task, whereas only primacy e↵ects were found in
the ME task, suggesting that di↵erent temporal weighting strategies were involved in these two tasks.