In their comment on the tolerance-noise covariation (TNC) method for decomposing variability by H. Muller and D. Sternad (2003, 2004b), J. B. J. Smeets and S. Louw show that covariation (C), as defined within the TNC method, is not invariant with respect to coordinate transformations and contend that it is, therefore, meaningless. Although the…

It has been proposed that it is possible to decompose changes in variability of human motor behavior into 3 independent components: covariation, task tolerance, and stochastic noise. The authors simulate learning to throw accurately and show that for this task the proposed analysis does not give an unambiguous answer to the question of what the 3…

Describes generativity theory based on the probabilities of many behaviors that are in competition and considers its effect on creativity. Topics discussed include previous and current generativity research, including behavior charts and frequency profiles; computer simulations; skills that improve generative processes; and creativity training in…