“Keep some aspect constant and improvise around it.”
The video demonstration below illustrates one example of this heuristic in action; The record motion is kept constant (baby scratches with only pitch adjustment for variation), while the fader hand is improvised.
Pivoting can be understood as a reductionist heuristic. When some aspect is kept constant, a limit is placed on the choices available to the performer. As a result, complexity is reduced, allowing for attention to be directed toward aspects of improvisation. Aside from the example below, you will hear this approach employed in many transform or 2 click patterns, when the performer keeps a constant unchanging rhythm on the fader while improvising the record motion.
Practicing and performing in this way helps to reduce cognitive load by reducing possible routes, while simultaneously encouraging new complimentary and highly connectable patterns to intuitively arise.