Detecting surface changes in a familiar tune: exploring pitch, tempo and timbre

Abstract

Humans recognize a melody independently of whether it is played on a piano or a violin, faster or slower, or at higher or lower frequencies. Much of the way in which we engage with music relies in our ability to normalize across these surface changes. Despite the uniqueness of our music faculty, there is the possibility that key aspects in music processing emerge from general sensitivities already present in other species. Here we explore whether other animals react to surface changes in a tune. We familiarized the animals (Long–Evans rats) with the “Happy Birthday” tune on a piano. We then presented novel test items that included changes in pitch (higher and lower octave transpositions), tempo (double and half the speed) and timbre (violin and piccolo). While the rats responded differently to the familiar and the novel version of the tune when it was played on novel instruments, they did not respond differently to the original song and its novel versions that included octave transpositions and changes in tempo.

Do rats ( Rattus norvegicus ) perceive octave equivalence, a critical human cross-cultural aspect of pitch perception?

“…This is in fact what has been observed in previous studies (e.g. [23,24]), see also infant head turning experiments where the critical measure is also attention (e.g. [31][32][33]).…”

Using isochrony, but not meter, to discriminate rhythmic sequences in rats (Rattus norvegicus).

“…Lastly, the results from the nonisochronous generalization test revealed no main effect of familiarity, F (1, 35) = 0.148, p = .703, η 2 = 0.001; group, F (1, 35) = 3.361, p = .075, η 2 = 0.067; nor interaction between familiarity and group, F (1, 35) = 0.020, p = .887, η 2 < 0.001. Once we shifted the frequency of the tones, the animals no longer recognized the familiar sequences (for similar results showing difficulties in the generalization across frequencies, see Crespo-Bojorque et al, 2022).…”

“…We used 40 female Long-Evans rats (3 months old). We determined our sample size on the basis of previous studies on music cognition with rats using similar paradigms and methodological approaches where statistically significant results were obtained (see Celma-Miralles & Toro, 2020b;Crespo-Bojorque et al, 2022). Rats were housed in pairs and exposed to a light-dark cycle of 12 hr/ 12 hr.…”

Recognizing structure in novel tunes: differences between human and rats

“…Food was delivered after each training session. Rats can learn to discriminate between sequences of tones in the same range as the ones used in the present study (e.g., Crespo-Bojorque and Toro 2016 ) and are sensitive to at least some temporal regularities in music (e.g.,Celma-Miralles and Toro 2020a , b ; Crespo-Bojorque et al 2022 ). In the present study, we used female rats because they tend to produce more responses than male rats.…”

“…The ability to readily process the complex hierarchical structures defining language and music might well be uniquely human, as other animals such as rhesus monkeys have failed to demonstrate sensitivities to increasingly complex patterns that mirror those present in humans (e.g.,Ferrigno et al 2020 ; Jiang et al 2018 ). Recent experiments suggest that rodents can track some rhythmic regularities in familiar tunes (e.g.,Celma-Miralles and Toro 2020a , 2020b ; Crespo-Bojorque et al 2022 ). However, it is possible that humans are the only species able to detect structure in novel tunes, compared to the same tones randomly arranged.…”