Studies investigating the influence of the learner's focus of attention, induced by instructions or feedback, on motor skill learning are reviewed. In general, directing performers' attention to the effects of their movements (external focus of attention) appears to be more beneficial than directing their attention to their own movements (internal focus of attention). Preliminary evidence is presented indicating that an internal attentional focus constrains the motor system by interfering with natural control processes, whereas an external focus seems to allow automatic control processes to regulate the movements. Support for the view that actions are controlled by their anticipated effects comes from research demonstrating functional variability in motor control, as well as the benefits of purposeful activity in occupational therapy. We explain these results in terms of the ideomotor principle of human actions (James, 1890) and its more modern derivatives (Hommel, 1996; Prinz, 1990, 1997).