What makes rhythm human? Music technology has introduced machine rhythms, perfectly-calibrated to electronically-perfected grids, yet we know that natural playing is more organic. Or, that is, we know we have certain intuitive preferences. How do those preferences and rhythms really work? And what does that mean for music technology?

Fascinating new research investigates more deeply, using – you know, science!

Here’s the summary of the research itself:

Although human musical performances represent one of the most valuable achievements of mankind, the best musicians perform imperfectly. Musical rhythms are not entirely accurate and thus inevitably deviate from the ideal beat pattern. Nevertheless, computer generated perfect beat patterns are frequently devalued by listeners due to a perceived lack of human touch. Professional audio editing software therefore offers a humanizing feature which artificially generates rhythmic fluctuations. However, the built-in humanizing units are essentially random number generators producing only simple uncorrelated fluctuations. Here, for the first time, we establish long-range fluctuations as an inevitable natural companion of both simple and complex human rhythmic performances. Moreover, we demonstrate that listeners strongly prefer long-range correlated fluctuations in musical rhythms. Thus, the favorable fluctuation type for humanizing interbeat intervals coincides with the one generically inherent in human musical performances.

Hennig H, Fleischmann R, Fredebohm A, Hagmayer Y, Nagler J, et al. (2011) The Nature and Perception of Fluctuations in Human Musical Rhythms. [PLoS ONE 6(10): e26457]

Hear that? One of the most valuable achievements of mankind! (Uh, that makes me want to practice a bit more, as I’m not sure I’d necessarily describe my last gig that way!)

James Postlethwaite, who sends this in, accompanies his news tip with an articulate letter considering the value of the research, so I’ll include all of it here:

Whilst reading the latest issue of the journal Nature (No.7372, Vol.479) I was surprised to se a picture of a TR-808 in the Research Highlights section, featuring research of note in other journals.

The research was about the correlations of rhythmic imperfections in human drummers, which correlate over a longer time period than the random singular imperfections that are inserted by some computer programs. At least I think that’s what it was, as I’m not a mathematician.

I do note that the sample size used in the statistical analysis was only 39 subjects, though the results were of a decent significance. The audio files are available in the supporting files section, CDM has a large readership, t-tests are very simple to run… Just an idea.

It does though serve as a nice reminder that a lot of the tools that musicians use nowadays do have roots in academic research, going back to the days of the early synthesizer. It also reminds me of a comment from a friend who used to own a 909; that one of the charms of this machine was the unique imperfection in the rigidity of the sequencer.
I don’t know if this has been corroborated by other people.

Finally, the piece in Nature magazine seemingly wasn’t written by a fan of electronic music, as it starts: ‘If you have endured much 1980′s pop music, you might agree that drum machines steal the soul from the beat. Their cold regularity is sometimes ‘humanized’ in the recording studio…’. Possibility of bias?

“Endured” 80s pop music? Yes, I’d say that counts as a bit of bias (just on the part of Nature). Imagine reading a story on bee populations, which began “Yeah, Bees. F*** bees.”

But the research itself looks solid and intriguing – and James is asking a variety of other interesting questions, so I’m going to open it up to discussion. Hope this is something we can follow up on. (Academics, attack!)

By the way, a quick search of Nature reveals that the journal regularly publishes material of interest to sound and music – worth noting, as there was a time when that wasn’t true. (Max Mathews was one of the first to help computer music break into the scientific mainstream.)
My search results
And, for example: Rhythmic synchronization tapping to an audio–visual metronome in budgerigars [hint: think tap tempo meets birds]

Updated: Nature wrote a quick blurb: Doctoring the beats
…though it seems from the excerpt that they either didn’t understand or tried to oversimplify the role of rhythmic variation in digitally-sequenced music. The study is, to me, more interesting.

World Science Festival 2009: Bobby McFerrin Demonstrates the Power of the Pentatonic Scale from World Science Festival on Vimeo.

At the World Science Festival in June here in New York, specialists – including musical specialist Bobby McFerrin – gathered to ask what in music we humans hear universally, versus what is culturally specific.

Is our response to music hard-wired or culturally determined? Is the reaction to rhythm and melody universal or influenced by environment? Join host John Schaefer, Jamshed Barucha, scientist Daniel Levitin, Professor Lawrence Parsons and musical artist Bobby McFerrin for live performances and cross cultural demonstrations to illustrate music’s note-worthy interaction with the brain and our emotions.

You can watch a series of five video highlights, but the one above is perhaps the most striking. (I believe it’s already more than made the rounds around the Interwebs, but, well, we can say we were all busy creating digital music.)

Notes and Neurons videos

It’s funny just how low the average person’s opinion of their musical ability can be. Ask an average “non-musician,” and they’ll often claim to be deaf to rhythm and pitch. Push the issue, though, and typically you’ll discover quite the opposite. Listen as the crowd laughs at discovering they all share some basic intuition about how pitch works. These are, after all, science and neurology types, not musicians.

Ah, you say, but this is just a crowd in New York. And most of us interact only with people in our own cultural circles. For me, that means people surrounded by pop music, Western harmony and counterpoint, chord changes derived from Protestant hymns — the lot.

What’s wonderful is that certain basic rhythmic and pitch elements – belying rich complexities of psychoacoustic phenomena underneath – do indeed seem to be universal. To me, that profound universality says something about what we share as human beings. At the same time, it makes me even more interested in all of the local details. When playing Balinese gamelan, some Western-trained musicians literally turned up their noses because they said the results sounded “out of tune.” Like a pungent flavoring in a foreign food, they discovered something unfamiliar. (I wonder if they would have the same reaction to sambal.) Of course, the underlying pitch systems are related to pentatonic (and heptatonic) pitch collections. And the same thing that disturbed one person has excited other musicians – not simply because it’s exotic, but because it can speak to something deeper in our hearing that we don’t get from other music.

Anyway, thanks to (noou) for this story, via IRCAM’s Eric Boyer; it really made my day. And it should certainly spark (ahem) some interest in neurology and the brain. Or, as I’m going to start saying whenever coming across something like this,

“Larry, what the hell just happened here?”