Late skill performance is dominated by perceptual-motor speed

Correct: C — Perceptual and psychomotor speed

Ackerman (1988) integrated Fitts' three-stage skill-learning framework with individual-differences data and proposed that as practice transforms a task from controlled to automatic, the predictive ability shifts: in the early cognitive phase, general intelligence and broad reasoning dominate; in the associative phase, perceptual abilities matter more; in the late autonomous phase, perceptual and psychomotor speed take over. The model accounts for why high-g learners gain a fast head start on novel complex tasks but why long-practice 'expert' performance can correlate weakly with IQ. It anchored later work on transfer-of-training and instructional design.