A CMPL alternative account of practice effects in numerosity judgment tasks

A reanalysis of the numerosity judgment data described in T. J. Palmeri (19 97) showed that the mean latency exhibits clear deviations from the power f unction as predicted by the component power laws (CMPL) theory of strategy shifting (T. C. Rickard, 1997). The variance of the latency systematically increases and then decreases with practice for large numerosities, a result that is also consistent with the CMPL theory. Neither of these results are predicted by existing versions of either the exemplar-based random walk or the instance theories. These findings suggest that numerosity judgment. Li ke other skills, reflects one at a time rather than concurrent execution of algorithmic and memory retrieval strategies.