In several visual search studies, the amount of practice on particular combinations of targets and distractors was equated in varied mapping (VM) and consistent mapping (CM) conditions. The results implicate a number of factors that play important roles in visual search and its learning: Experiment 1, using small sets of letters, demonstrated almost equal VM and CM performance, and slope reductions during practice for both, suggesting the learning of efficient attentive search based on features, and no important role for automatic attention attraction. However positive transfer effects occurred when previous CM targets were re-paired with previous CM distractors, even though these targets and distractors had not been trained together. Also, the introduction of a demanding simultaneous task produced advantages of CM over VM. These latter two results demonstrated the operation of automatic attention attraction. Experiment 2 used novel characters for which similarity and feature overlap were controlled. The design and many of the findings paralleled Experiment 1. In addition, enormous search improvement was seen over 35 sessions of training, suggesting the operation of perceptual unitization for the novel characters. A multi-factor theory of automatization and attention is put forth to account for these findings and others in the literature.