FIG. 1.
(Color online) (A) The virtual vocal throwing task. Subjects threw a ball at a target using neck-skin acceleration amplitude above their lowest phonation level (ACCamp, in dBLPL) and changes in fundamental frequency [Δf0, in semitones (st)]. Though the sling is pictured, it was not visible during practice. (B) Visual display showing the sling and ball trajectories for three exemplary trials. α and β represent angle (in radians) and stretch (in pixels). (C) The three plots show frame-based values of Δf0 and ACCamp for the three trials. Also, arrows pointing down and up show the start and release values for the slingshot, respectively. Notice that in all three throws, there are moments where one variable is stationary and another is changing. (D) The execution space indicates the amount of error in pixels (pix) for combinations of slingshot release values of Δf0 and ACCamp (values shown for three trials).