Acquisition of procedural skills from examples.

Three experiments were run in which Ss first memorized examples of input-output pairs and then generated the outputs for a series of new inputs by analogy to the original examples. Ss first performed these mappings by explicit analogy to an example, but with practice they learned to make these input-output mappings directly without reference to the examples. Ss sped up as a power function of practice over a day (Experiment 1) or days (Experiments 2 and 3). Ss developed a directional asymmetry such that they were slower to calculate the input from the output than the output from the input (whereas initially they had not been). Ss showed similar speed up in their ability to recall the original examples but did not show the same directional asymmetry. Initially, there was some transfer from practicing the procedure to recalling the examples, but this diminished over days.