Mostofsky et al. (
2000) suggested that visuomotor sequence learning in children with HFA may be different from that of TD and ADHD children. At the outset, this appears to be inconsistent with the present results. However, there are several differences between their study and the present one. First, our sample of ASD children consisted exclusively of AS patients, whereas their ASD patients included children with HFA. Barnes et al. (
2008) reported that the implicit learning of spatial context and temporal sequences was unimpaired in their ASD participants, which consisted primarily of AS children (10 out of 14). Therefore, it is possible that distinct ASD cohorts show different learning profiles in visuomotor sequence learning (e.g., sequence learning may be affected in ASD children besides AS children). Second, Mostofsky et al. (
2000) employed a simple sequential response time task, in which participants just need to follow a visual target. The 2 × 10 task requires participants to commit visuomotor sequences to memory. The difference in mnemonic demand with regard to performing the tasks might explain this discrepancy (e.g., a task demanding a mnemonic process may be more impervious to dysfunctions in AS children). Unimpaired implicit learning as found by Barnes et al. (
2008) is consistent with this possibility; the complex spatial and temporal patterns might require more mnemonic processes in their task than in the simple sequential response time task. Third, the explicit aspect of the 2 × 10 task might lead to results different from those obtained by Mostofsky et al. (
2000). Learning a visuomotor sequence in a practical setting often includes the explicit exploration of hidden patterns before the implicit automatization process. The 2 × 10 task had been devised to capture both processes, with more emphasis on the explicit exploration process; a complex visuomotor sequence is consciously explored and learned by trial and error, and elaborated once the sequence has been established. In addition, Gidley-Larson and Mostofsky (
2008) found that, compared with both ADHD and TD children, HFA patients showed a similar degree of improvement as the ADHD patients in carrying out a rotary pursuit task; however, the degree of improvement was less when they needed to learn a pattern with another interference pattern. Thus, the preserved learning efficacy (i.e., similar degree of improvement) is common between their results and ours. In the present study, however, we did not ask the participants to learn multiple hypersets; therefore, we were unable to examine whether multiple hypersets would interfere with each other in the 2 × 10 task. These possibilities will form the basis of future investigations.