Trained 256 male and 244 female undergraduates of Caucasian ancestry on the United States Air Force Rotary Pursuit apparatus for 100 20-sec trials spaced by 10-sec rests. Results show that: (a) mathematical forms of the percentage time-on-target curves were independent of aptitude; (b) curves at 5 ability levels were exponential and highly predictable (average error < 0.3%); (c) significant trend differences revealed early divergence and later convergence; (d) initial ability, acquisition rate, and final level were positively correlated; (e) no significant age differences were found within the range of 17-41 yr.; (f) men were superior to women in tracking skill (more accurate, less variable), maintaining an average lead of about 7.8% time on target; (g) interactions with practice were found between aptitude and sex; (h) intratrial SIGMA2 values rose rapidly to a peak, then fell gradually with training; (i) intertrial GAMMA values decreased (based on Block 1) from Blocks 2-20 and increased (based on Block 20) from Blocks 1-19; and (j) differentiation between Ss of low and high aptitude was maintained at advanced levels of proficiency (GAMMA > .50) despite the decreasing intertrial GAMMA pattern. (33 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)