Researchers from the Department of Life Sciences at the University of Trieste, in collaboration with the Sapienza University of Rome, have discovered that the preference of animal species, both human and non-human, for consonant sounds would be partly physiologically determined. The hypothesis at the origin of the study, conducted on one hundred and thirty hatchling chicks, is that the constituent elements of musical abilities - of humans and animals - have a biological root, shared between species that are also phylogenetically distant, and do not depend solely on culture and musical experience.

‘Previous research by the University of Trieste had already led to the discovery that chicks, like other species, prefer so-called consonant musical intervals. The latter, in fact, are those that most resemble the sound produced by living beings, while the dissonant ones recall the lesser harmony of environmental sounds,’ explains Andrea Ravignani, professor of general psychology at the Department of Human Neuroscience at the Sapienza University of Rome. ‘At the time, we did not know the reasons for this; today, however, we know – thanks to studies conducted together, the University of Trieste and the Sapienza University of Rome - that consonant intervals are produced in acoustic social signals.’

The research was carried out on one hundred and thirty hatchling chicks; once hatched, the chicks – which do not require any parental care, neither to develop their vocal repertoire nor to walk – were reared for four days, in pairs, in rectangular cages at controlled room temperature. 

The following calls were recorded for each chick in soundproof pens: contact calls emitted by the chick when it feels discomfort because, for example, it is separated from the hen, brooding calls emitted in pleasant situations and food calls emitted when the chick identifies a profitable food source. These calls are part of a complex vocal code that chicks develop from hatching to adulthood to communicate their needs to other conspecifics and to express the positive or negative nature of a situation they are experiencing. 

The researchers stimulated the production of each type of call by the chicks by gradually recreating the natural situation associated with each one. Specifically, they recorded: contact calls, leaving the chicks alone in the empty pen after separating them from their rearing mate and the imprinting object; brood calls, placing an imprinting object in the centre of the pen after initial isolation; food calls, placing a dish of food in the centre of the pen after removing the imprinting object.

After analysing the minimum and maximum peaks of the fundamental frequencies and calculating their ratio, the study revealed a prevalence of perfect consonance in all types of calls, confirming the idea that consonant sounds are intrinsically present in animal communication. The only recorded dissonances were found in situations of particular distress, such as isolation contexts.

‘This research could open up promising applications: a chick that emits a sound with a certain frequency is probably indicating a certain type of situation, and we now know that the most harmonious calls are those emitted in the most pleasant situations,’ explains Cinzia Chiandetti, associate professor of psychobiology at the Department of Life Sciences at the University of Trieste. ‘Depending on the dominance of consonances or dissonances, we will be able to understand the emotional status of the animal associated with the context in which it finds itself: we are not so far from being able to imagine devices capable of recording the calls and returning the level of comfort or stress of the animal in front of us, even of chickens that, as the writer Andrew Lawler would say, are the birds that have nurtured civilisation’ concludes the expert.

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Full study published in Biology Letters

Chicks produce consonant, sometimes jazzy, sounds

Gianmarco Maldarelli1,2, Andrea Dissegna1, Andrea Ravignani3,4,5 and Cinzia Chiandetti1

1Department of Life Sciences, University of Trieste, Trieste, Italy

2Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-Universitat

Bochum, Bochum, Germany

3Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands

4Center for Music in the Brain, Aarhus University, Aarhus, Denmark

5Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy