Two non-verbal cognitive systems, an approximate number system (ANS) for extracting the numerosity of a set and a parallel individuation (PI) system for distinguishing between individual items, are hypothesized to be foundational to symbolic number and mathematics abilities. However, the exact role of each remains unclear and highly debated. Here…

Discusses the problems involved in matching differences between learners and differences between different types of media to improve the learning process. Thirty-eight references are cited. (CHC)