I was only vaguely aware of Tribe back in the nineties. I knew them as the preferred hip-hop group for my white friends who were put off by the harder edges of Wu-Tang and the west coast gangsta rappers. I encountered “Scenario” and “I Left My Wallet In El Segundo” at parties, and found them entertaining, but didn’t feel compelled to go any deeper.

More recently, when I got into hip-hop scholarship in earnest, I started listening to Tribe for real. I downloaded “Check The Rhime” and was floored by the production.

The beats hit hard and simple; the samples are mysterious without being inaccessible; and the frenetic chorus contrasts excitingly with the buttery-smooth verses.

As I’ve been digging into more Tribe songs, I’ve been consistently impressed by their level of musicality. The tracks are accessible and fun, but on close scrutiny they’re dense with ambitious ideas. I’m particularly fond of the six-bar loop in “Electric Relaxation.”

Anyone can use an unusual phrase length, but it takes real artistry to make it sound so smooth and natural.

As for the movie itself, I enjoyed it and learned a lot. Some longtime Tribe fans of my acquaintance complain that it focuses too much on the present and doesn’t spend enough time on Tribe’s prime back in the 90s. That’s a fair point, and I certainly wouldn’t mind having more context on hip-hop’s golden age. But I thought the movie did a great job digging into the complicated relationship between the members of Tribe. I agree with Rob Fields’ review:

By far the most moving core of the film is the peek that it offers inside the relationship between Jarobi and Phife. It’s rare to see examples on the screen of two black men who have such unconditional love for each other.

The movie confirms that Q-Tip is central force behind Tribe, both on the production side and in setting the overall tone. But the other guys must have brought something to the table, even if it was just peer pressure. Tip’s post-Tribe music has been, you know, fine, but there hasn’t been anything remotely like “Check The Rhime.” When he calls himself “the Abstract,” Tip isn’t kidding. Phife and the others seem to have kept Tip’s ideas more down to earth, which helped make them stronger. The conflict between Tip and Phife is as much a part of their story as their creative partnership. Here’s an interview with director Michael Rapaport if you want some background.

One of the high points in the movie is Tip talking about his late father. He talks about getting the beat for “Can I Kick It” from a Dr Lonnie Smith record that he associated with his dad.

I’ve heard other hip-hop artists talk about sampling their parents’ music as a way of connecting to the older generation while still forging a new sound with present-day relevance. I know a lot of lame instrument-playing musicians who imitate the music of their parents out of an anxiety that they might deviate too far from what’s musically acceptable. Taking samples and transforming them makes for a healthier relationship to your ancestors.

Speaking of samples, I heard “Bonita Applebaum” for the first time in the movie.

I was delighted to discover the source of the sitar sample in the Fugees’ version of “Killing Me Softly.” And where did Tribe get that sitar from in the first place? A totally ridiculous song by Rotary Connection called “Memory Band.”

The real art of sampling isn’t just finding some great song and repeating the hook; it’s finding a hook in a terrible song and using it to build a new great song. But here’s the crazy thing. The main groove under the verses in “Check The Rhime” comes from “Baby, This Love I Have” by Minnie Riperton. Guess who the female singer in Rotary Connection was?

Q-tip seems like the exact kind of crate-digging sample geek who would know about the Minnie Riperton connection. A man after my own heart.

The film was also my first exposure to the concept of the pause tape, which is how a lot of hip-hop producers got started back in the day. Before digital samplers became so cheap and accessible, pause tapes were the easiest way to create loops. You’d put your tape recorder on pause and cue up the record to just before the part you wanted to sample. When the downbeat of the sample started, you unpaused the tape, and paused it again when the sample ended. Then you cued the record back up to the same spot, and repeated, and repeated, and repeated. Here’s a video of the process.

Tribe’s influence on present-day music can be felt in unexpected ways. Check out this remix of “I Left My Wallet In El Segundo” around the 0:35 mark.

That little phrase, slowed way down, became the basis for “A Milli” by Lil Wayne. Hear the process at work.

I hope this movie inspires more movies about golden-age hip-hop, and I hope they continue to dig into the nuts and bolts of the creative process. People hear so much hip-hop but know so little about where it comes from, what it means, what the connections are. That ignorance extends to many of the musicians I know. Keep the documentaries coming!

You can trace the ancestry of music like you can trace the ancestry of a person

Each new song is built using the same modular components as the other songs of its time and place, the way that all humans share the same genetic toolkit. My sister and I are like two different songs from the same album by the same band. My cousins are like songs on different albums by bands with overlapping members. Here’s a diagram of my entire extended family – parent/child relationships are green and spouse/partner relationships are red.

The ancestry of music is more complicated than the ancestry of humans. A better model for music is the evolution of microbes, with a lot of horizontal gene transfer happening. Biologists use the term “gene cassettes” to describe the semi-self-contained hunks of DNA that bacteria swap back and forth. The analogy to music fans spreading memes by passing tapes around couldn’t be any more perfect.

Some musical relationships do conveniently lend themselves to family tree-like representation. The practice of sampling and quoting existing songs creates a particularly clear and unambiguous set of relationships well-suited to network diagramming. The internet has several handy sample databases, including the Rap Sample FAQ, Whosampled.com and Wikipedia. I’ve been hard at work the past year or so making sample maps visualizing the more interesting chunks of data.

See all of my sample maps here.

Sampling is the easiest set of relationships to diagram, but I could draw similar charts for use of particular scales, chords, rhythmic figures, melodic motifs, rhyme schemes, combinations of instrument sounds, and all the other memetic nuts and bolts of music.

A few really successful memes make up most of the music we hear

Some musical memes are better at getting themselves copied than others, the way genes for color vision or opposable thumbs are good at getting themselves copied. Here in America, the most successful memes include the backbeat, the one-four-five chord progression and the blues scale.

To illustrate just how widespread a musical meme can get, here’s a video called “Four Chords, Thirty-Six Songs.” In the key of C, the four chords are C, G7, Am, F. (Some coarse language towards the end.)

The video barely scratches the surface of all the songs, famous and not, that have used those four chords. So why is this chord progression such a big hit? For one thing, it’s easy to play on piano or guitar or whatever. For another, the four chords sound good in any sequence or combination, spaced out on any harmonic rhythm. They have a wistful yet still uplifting mood that suits a variety of musical statements in a variety of styles.

Computers make recombining and resequencing the memes effortless

Pre-computer, composing and recording a song was a slow and effortful process. You wrote the song out or memorized it. Then you got a band together and they read the song, or you repeated it to them until they memorized it. Then you rehearsed it a bunch, and then recorded it from beginning to end. Sometimes you had to record many takes to get a good one. To get a polished, professional-sounding result generally required expensive gear operated by highly specialized engineers.

You can still operate that way if you want, but computers offer some faster and easier alternatives. I prefer to write by improvising into the sequencer or digital audio editor, picking the best patterns and editing them into shape. The computer gratifyingly collapses improvising, composing and recording into a single act. Making music electronically is like being able to type out any DNA sequence you want and immediately seeing how it will look as an organism. You can skip the tedious embryonic development of notating, rehearsing and memorizing. Technologies like MIDI, sampling and pitch-detection software let you read any existing musical genome and resequence it to your heart’s content.

All this freedom is positively alarming to some of the musicians I know, who view it as evil or immoral in some way. I find that the computer eliminates some of the labor, but doesn’t do the imaginative work for you. The computer makes it effortless to spin out ideas, but you still need to select among them and decide which are the good ones. The creative act itself stays the same as it always has been; there’s just less friction.

Towards a unified theory of musical evolution

A genome is an algorithm for getting itself copied by generating the proteins and other structures making up an organism. A group of memes (a memeplex, as Susan Blackmore puts it) is an algorithm for getting itself copied by generating performances and recordings. What makes a song likelier to get itself heard, and eventually copied or adapted? Exact copying of previous generations of songs is a bad long-term strategy. Tastes change, like the way the environment changes for organisms. A meme that was successful yesterday may not be successful tomorrow.

Total originality is a bad strategy too. It’s easy to be original, to create a piece of music with no precedent or borrowing from anything existing. Bang randomly on a piano and you’re probably going to play something that’s never been played before. It’s likely that your random banging will mostly be annoying. Chances are, a random DNA sequence won’t make for much of an organism either.

To be liked enough to be copied and imitated, your song will need to be substantially familiar. Forming an emotional connection with the listener requires a lot of shared vocabulary and associations. What works the best in music, as in biology, is a minor mutation on an existing successful replicator. Most mutations will make it harder to get copied, but a lucky few improve your chances dramatically.

See a version of this post on Quora.