Sapienza, in collaboration with the University of Trieste, carried out a study on the preference of animal species, both human and non-human, for consonant sounds, which is partly determined physiologically. The hypothesis at the origin of the study, conducted on one hundred and thirty featherless chicks, is that the constituent elements of musical abilities - both human and animal - have a biological root, shared even between phylogenetically distant species, 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. As a matter of fact, the latter are those that most resemble the sound produced by living beings, while the dissonant ones recall the lesser harmony of environmental sounds”, says Andrea Ravignani, Professor of General Psychology at Sapienza’s Department of Human Neuroscience. “At the time, the reasons for this were unknown; today, however, we know - thanks to studies conducted together - that consonant intervals are produced in acoustic social signals”.

The research was carried out on one hundred and thirty featherless 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 a controlled room temperature.

The following calls were recorded for each chick in soundproof arenas: 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 by leaving the chicks alone in the empty arena after separating them from their rearing mate and the imprinting object; brood calls by placing an imprinting object in the centre of the arena after initial isolation; and food calls by placing a food dish in the centre of the arena 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 harmonic 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 may come to understand the emotional status of the animal associated with the context it is in: we are not that far from being able to imagine devices that can record the calls and return the level of comfort or stress of the animal in front of us, even chickens that, as the writer Andrew Lawler would say, are the birds that have nurtured civilisation”, concludes the expert.

Further Information
Andrea Ravignani
andrea.ravignani@uniroma1.it