How do listeners perceive whether a singer is in tune or not? It is challenging to define it objectively. In spite of the difficulties involved, Pauline Larrouy-Maestri, a researcher at the Max Planck Institute and a scientific collaborator with the department of psychology of the University of Liege, has succeeded in doing so. By quantifying objective criteria for judging singing accuracy with the help of computer programs, and by comparing the subjective judgements of music professionals and laymen, she succeeded in evaluating the perception of accuracy among the two groups. This research greatly alters the commonly-held idea that music professionals are better equipped to judge voice accuracy.

Whether we are listening to the radio, watching one of the many reality TV shows aiming to discover the latest star or even listening to a relative singing their heart out under the shower, we are constantly evaluating the singing accuracy of our peers. Whether or not we do so unconsciously, objectively or based on informed knowledge, we all have our own criteria for deciding where singers appear on a scale ranging from those who do not have a note in their head to those who are professional singers. For the layman, making a crude distinction between the two extremes seems to be childsplay. The question becomes a lot more difficult, however, when the distinction becomes the subject of scientific research. What does “singing in tune” actually mean? And what does “knowing whether a song is in tune” mean? The answer can be multi-faceted. Different phenomena come into play. There are questions of a physical or acoustic nature, questions related to cultural heritage, very objective criteria and other criteria that depend on individual appreciation etc. It is therefore very difficult to know what judging singing actually refers to.

These are the complex questions that interest Pauline Larrouy-Maestri, a researcher at the Neuroscience Department of the Max Planck Institute in Germany and scientific collaborator at the Psychology Department of the University of Liege. She had an article(1) published in PLOS ONE devoted to comparing the judgement of layman listeners and music professionals. It is a study based on rigorous quantitative criteria, whose conclusions have raised more than a few eyebrows. Indeed, in many respects, it would appear that “non-musicians” have no reason whatever to be embarrassed about their faculty to determine what is accurate and what is not. The study has yielded surprising conclusions.

Identification of objective criteria

Between music studies at the Royal Conservatory of Mons and a Master’s in logopedics obtained at ULB, the way was almost paved for Pauline Larrouy-Maestri. Attracted by scientific research, she met Dominique Morsomme, head of the Voice Therapy Unit at ULg, and began a thesis on the perception of singing accuracy. “I wondered what led us to decide whether a song was accurate or not. There are many television programmes which expose us to this kind of voice evaluation but nobody really knows how to identify the factors involved in deciding if singing is accurate or not”.

For the young researcher, it was first necessary to concentrate on an objective and quantified means to measure singing accuracy. To do this, she first used optimised computer programmes for acoustics and music for the purposes of her research. The voice, like all other sounds is a measurable acoustic signal. In the case of untrained voices, it is just a simple question of extracting the fundamental frequency for each note sung and to measure the relationship between the different frequencies to verify whether the singing is accurate or not. “These tools enabled me to quantify three music criteria: melodic contour errors, when the frequency of the note varies in an unexpected direction, incorrect intervals, gaps that are too large or too small between two notes, and finally changes in tonality during the piece. These changes occur when an interval error has not been compensated for afterwards. The singer has not corrected it and continues in another tonality”.

The computer against the experts

Once the computer programme was developed, a database needed to be created. The speech-language pathologist took her study to the streets and, with the help of students, recorded 166 volunteers who agreed to sing “happy birthday”. This is a simple piece which everybody knows. This sample included men, women, young people, elderly people, shy people and others who love to sing…“The only condition, says the researcher, “was that they did not have a trained voice. I wanted the sample to be exclusively made up of people who had not formally learned to sing”.