Machine rhythm: the steps on a Roland TR-808. Photo (CC-BY-SA) Brandon Daniel.

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.