Decision strategies in loudness judgments of time-varying sounds inferred from two psychophysical tasks
Invited paper
Ircam
Wednesday 3 june, 2015, 14:00 - 14:20
0.2 Berlin (90)
Abstract:
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 effects 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
L<sub>Aeq</sub> or N<sub>5</sub>. However, such effects 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 effects were observed in the level-discrimination task,
whereas only primacy effects were found in the ME task, suggesting that
different temporal weighting strategies were involved in these two tasks.