Behavioral measurement of state-transition time between ambiguous melodies, a follow-up

Abstract

The purpose of this study is to investigate melody recognition processes in the brain using ambiguous auditory stimuli. Some stimuli we encounter in our environment are ambiguous. Necker cube is a famous example in vision. However, it has not been studied systematically in hearing. We proposed a novel form of ambiguity involving two illusory melodies implied by a very simple stimulus consisting of two sustained tones (A4 and E5) and an intermittently repeated tone (C5). One heard either the phrase C5-A4-C5-A4, C5-E5-C5-E5, or the physical stimulus, that is the repeated middle tone. We presented introductory melodies (C5-A4-C5-A4 or C5-E5-C5-E5) to reduce ambiguity before starting ambiguous melodies. We then measured the transition time that elapsed until the subject heard a different melody from the introductory melody. In this report, we used B4 or D5 for intermittently repeated tone other than C5 to investigate how transition time changed. The different behaviors for different middle tones had some bearing on how one preferred to or tended to form a melody in one's mind. When repeated tone was D5, D5-E5-D5-E5 tended to be preferred to D5-A4-D5-A4. There was no preference between upward and downward phrase for B4.