A few months ago, in the philosophical quest to understand why music affects us the way it does, a new scientific line of thought was thrown open. Writing in the June issue of the journal Emotion, Meagan Curtis and J.J. Bharucha, researchers from the Music Cognition Lab at Tufts University, sought to link the emotion of melancholy to a specific pitch pattern known as the minor third. A classic example of a doleful song that uses a minor third is the English folk tune Greensleeves; another is the Beatles’ Hey Jude, an anthem of such sorrow that it really shouldn’t be giving its listeners sage advice on how to take a sad song and make it better.

Mournful: Hey Jude by the Beatles is in the minor third. AFP

But Curtis and Bharucha’s most surprising hypothesis was that the same minor third that made these songs sad also made speech sad. In one experiment, actors were asked to recite short sentences with varying emotional inflections (samples of these recitations are available on the Lab’s website, and you’ve never heard such morose renditions of “Let’s go" and “Come here" in your life; the voice of the lady saying “Ok" practically drips with grief). Each of the actors, without realizing it, laced their gloomy soliloquies with the same feature found in Hey Jude or Greensleeves. Of all sad words of tongue or pen, the saddest, apparently, are these: The ones pronounced with a minor third.

A minor third is, essentially, a technical device—a musical interval that stretches across three semitones, innocuous enough when played on its own. The Curtis-Bharucha paper has thus stirred up some lively debate that resembles the chicken-egg problem in its recursive nature. Which came first: the sad minor third, or the cultured perception that a minor third is sad? Nothing, after all, can be inherently melancholic about a musical interval. On the other hand, there must be a reason why composers have persisted in using the minor third in their saddest songs—and persisted so effectively that, like Curtis and Bharucha’s actors, we instinctively associate the minor third with sadness.

Minor thirds show up in Hindustani and Carnatic ragas as well. Malkauns and Darbari Kannada feature prominent ones in their flattened Ga notes, and these ragas can, interestingly enough, sound profoundly despondent when played or sung with a slow, deliberate gait. But of more interest in the Carnatic system is that ragas come already classed according to their rasas—to the emotions they are intended to invoke. The karuna rasa, a complex sentiment that is undercut by a rather existential sadness, is said to be contained, for instance, in ragas such as Charukesi, Ahiri or Sahana.

There is, I think, immense scope for the pursuits of musicologists and psychologists here, the way Curtis and Bharucha investigated the minor third. What precisely about the structure of Ahiri (to take one example) caused it to be classified as sad? Why is a raga like Mukhari often perceived to be sad, even though experts insist it is anything but? Do Charukesi or Malkauns sound gloomy even to, say, Finnish or Bolivian ears, which have never heard these ragas before? The answers will hardly be definitive, but they can reveal volumes about how we relate to the world of sound around us.

Write to Samanth Subramanian at raagtime@livemint.com