Interstimulus interval dependence of the loudness difference limen obtained by taking into account the presentation order effect

Abstract

This paper describes the interstimulus interval dependence of the loudness difference limen obtained by taking into account the presentation order effect of sound stimuli. A paired comparison experiment of pure-tone sounds was carried out at different interstimulus intervals, and the experimental data were analyzed, taking into account the presentation order effect. The following two characteristic effects were obtained. First, the difference limen changed depending on the interstimulus interval. A logarithmic relation was found between the difference limen and the interstimulus interval. The difference limen was about 0.6 to 1.6dB at an interval of 0.5 to 64 s. Second, the order effect also changed depending on the interstimulus interval. The sound presented first was perceived as being louder than the sound presented second at an interval of 0.5 to 4 s, and the sound presented second was perceived as being louder than the sound presented first at an interval of 16 to 64 s, although the sounds were of the same sound pressure level. When the interval was 8s, the sound presented first was perceived as being as loud as the sound presented second. Based on the above findings, we estimated the region where the difference in loudness could not be detected. The obtained results show that the region is not symmetrical for the upper and lower boundary levels.