THE IMPORTANCE OF PITCH SEQUENCES. Nick called my attention to this article on pitch sequencing by Ken Arneson from 2014 which Nick had seen recommended several times. Pitchers and hitters talk about pitch sequences a great deal but analysts (sabermatricians) have not had much to say on the subject.
The key to Arneson’s argument is that there are two different physical systems that a batter uses. One is conscious; a batter may decide to look for a certain kind of pitch on the next pitch, say a fastball outside. “But once the pitcher releases the ball, this kind of conscious prediction mechanism is far, far too slow to be of any use.” Instead, the batter must must rely on the second system—“a much faster, subconscious, automatic system to predict the actual flight of the ball, and to send the muscles in motion to meet the ball.”
Sequencing is important because the second system has a “recency bias”; it assesses the speed and movement of a pitch by comparison with the most recent pitches the batter has seen. The speed, location and movement of the most recent pitch will affect the brain’s automatic prediction of the speed, location and movement of the next pitch.