Please have patience, another look back?

[SC Ump]

When the pitcher receives the ball in the circle, the runner must immediately decide which base she wants to go to. My opinion is that what "immediately" means would be based on the umpires interpretation as related to what was happening on the specific play. In almost all the circumstances I can think of, if the player is moving toward first and if the pitcher then receives the ball in the circle, that first nanosecond of movement by the runner following the receipt of the ball has committed her to first.