The issues of skill specificity and transfer of training were examined from an aptitude-treatment interaction approach. The current investigations extended A.M. Sullivan’s (1964) approach by using a procedural transfer task and training conditions that differed in the amount of training task practiced and the degree of training task similarity to the transfer task. Tow experiments were conducted with 232 college students. Experiment 1 examined the effects of a length-of -training manipulation on reasoning ability and transfer task performance relationships, and on the amount of transfer. Experiment 2 evaluated the effects of 2 training tasks that differed in terms of similarity to the transfer task on ability-performance relationships and the amount of transfer. Results suggest that Sullivan’s approach partially generalizes to the acquisition of procedural knowledge.