It has become increasingly common for theories to rely on a constraint that 1 object cannot be in more than 1 place at the same time. Analysis suggests that a 1 object--1 place--1 time constraint as literally stated is false, that a modified constraint is biased toward the visual modality, that it may not be a correct description of the physical…

Three problem-solving strategies--working backward from the unknown, forward from the given, and mixed--were applied to interrelated algebra equations. The mixed strategy was most popular and most efficient with grouped variables. Memory load or information-processing load differences among the strategies were evident. (CP)