What is learned in procedural learning? The case of alphabet arithmetic

This research pursued a fine-grained analysis of the acquisition of a procedural skill. In two experiments (n = 29 and n = 27), adults practiced 12 alphabet arithmetic problems (e.g., C + 3 = C D E F) in two sessions with 20 practice blocks in each. If learning reflected speed up of a counting algorithm, response time (RT) speed up should be proportional to the number of counting steps (+ 1, + 2, or + 3). Instead, we found about 50% of RT gains occurred in the first six blocks of practice during which speed up was parallel for + 1, + 2, and + 3 problems. In both experiments, RT initially was a linear function of addend size, reflecting a letter counting strategy. Mean RT for + 3 problems was eventually equal to + 2 problems, which suggests that speed up reflected a gradual shift to associative fact retrieval. Trial by trial strategy self-reports in Experiment 2 revealed that the proportion of trials reported as memory retrieval as opposed to counting predicted 96% of the variance in RT as a function of addend size and practice block. As such, the results provided no evidence for speed up of a counting algorithm and indicated that skill acquisition for this task entailed speed up of task-general processes independent of addend size and rapid transition from counting to fact retrieval. (PsycInfo Database Record (c) 2020 APA, all rights reserved).