Before turning to the aging effects on AST cognitive control, it is worth noting several features of the prosaccadic eye movements that were preserved in the older population. The PST data allows for a baseline comparison against the three ASTs across the age groups. The reaction times of prosaccades were relatively well preserved in the older group (mean = 175 ms vs. young group mean = 154 ms), showing that processing speed was preserved in the older group. It is important to note that there was no evidence that these fast reaction times were achieved at the expense of accuracy. The older group (mean = 0.64°) was not significantly different to the prosaccade spatial accuracy of the young group (mean = 0.58°). The frequency of prosaccade errors was negligible for both age groups. This confirms that prosaccades are fast, automatic responses that are relatively well preserved in healthy aging. As expected, prosaccade latencies were significantly faster than AST latencies for both the young and older adults, reflecting the additional processing component required for motor programming in the AST (Hallett, 1978).