Is Roy Lichtenstein a great comic strip artist? No, he’s a great avant-garde artist who uses comic strip style. This is confusing. But you need to understand this to understand why Lichtenstein is in the Museum of Modern Art.
It’s similarly confusing that there are certified Free Improvisors—people like Derek Bailey dedicated to open-minded experimentation with sound, probably filed under Jazz—who dabble in rock forms while making their stuff up. Just to add to the confusion, we can construe the rock moments of their output as rock hooks even though their intent is not to rock. (Anyway, their project is not to rock; I suppose one can’t be sure about their momentary intent.)
Recurring to the idea of three levels of improvisation (see previous post), what level would this rock-dabbling be on? Level 2, where you choose a song structure? No, it must be Level 3, where you choose what’s going to count as music. Given how fundamentally different free improv is from any popular genre, though, I wonder if this is really a Level 4 decision between keeping your sovereignty over what counts as music and temporarily (but freely!) giving that up?
Whatever. Let’s listen to an example.
Even for Hooks purposes I wouldn’t presume to pick out a greatest anything in improv. Improv is like lovemaking; the greatness of any moment is just that it belongs to a continuum of good experiences.
But we can exhibit something that is characteristically delightful about improv, like the sudden emergence of a melodic hook or a funky groove in wild-free-noisy playing—the subject at hand. And here’s an example of that from Derek Bailey’s Mirakle album:
It’s especially true in improv that hooks for performers aren’t necessarily the same as hooks for listeners. For example, improvisers love it when a sound surprises or confuses them while they’re producing the music—“Is that coming from the cello or the drums?” But improvisers do cherish the effective interruption of whatever sort, which is a striking event for listeners too. In the strange world of reinventing music, a rock hook can be a fine interruption.
Another, rather different way in which a hook can show up in improvised music is if an improviser uses a radio to bring in real-time sound. In 1966 the seminal improv group AMM listed two members playing “transistor radio,” Cornelius Cardew and Keith Rowe, one of whom (I think probably Rowe) captured this refrain from a pop station in the midst of a 21-minute session:
We seem to be hearing this from miles away; we barely feel it touching the outer membrane of our improvised music cocoon. It gives us just the right faint mindfulness of the world we’re being detached from.
 Edwin Prévost, No Sound Is Innocent (Matching Tye: Copula, 1995), p. 19.