[P1] Poster: Day 1

[P1-40] The sound octave equivalence in a songbird as shown by the event-related brain potentials and the operant behavior.

*Rin Ito¹, Yukino Shibata^1,2, Kazuo Okanoya¹ (1. Teikyo University, 2. Hokkaido University)

Keywords:

songbirds,octave,operant conditioning,event-related potentials

Octave equivalence is a psychological phenomenon in which two sounds that have the relation of doubling of wavelength are perceiving as being similar to each other. This is one of the fundamentals in music perception related with timing and pitch. We asked whether a species of songbirds, the Bengalese finch, perceives such relations in sounds. Because Bengalese finches sing complex songs with multiple syllables comprising of harmonics, we hypothesized they might possess such perceptual mechanisms. We tackled the question by the event-related brain potentials and the operant behavior. We first measured local field potentials from the higher order auditory area of the finches. We used the oddball task in obtaining the miss-match negativities (MMNs) from novel sounds over familiar sounds. We used the latencies and the negative voltages of the MMNs to construct a cross-correlation matrix and then analyzed it by a hierarchical clustering. We found birds placed sounds in the octave relations in proximity than the one with 1/2 octave relation, suggesting the possibility that they are perceiving the octave equivalence. We then trained the finches to respond discriminate between sounds with different pitches, and then tested whether a novel sounds with octave high or low might be perceived as being similar with the original sound. This behavioral experiment is ongoing and we will be able to show the results in the conference. The study will show whether or not a species of the songbirds, with similar usage of sound signals with our music, perceives octave equivalence. (Work supported by JSPS 24H05160 and 23H05428 to KO).