Figure 4.

Activation of the visual, retrieval, imaginal, and manual modules in the decomposition of “67.” Time is given in seconds (sec). Lengths of boxes reflect approximate times the modules are engaged. The horizontal lines represent the firing of production rules. Brackets indicate subtasks of activity controlled by a setting of a goal. These subtasks are initial encoding of the problem, calculation of 39 as part of 67, calculation of 28 as the other part, calculation of 22 as part of 39, calculation of 17 as the other part, calculation of 13 as part of 22, calculation of 9 as the other part, special decomposition of 13 into 7 + 6, keying of 7, keying of 6 and retrieval of past decomposition 22 = 13 + 9, keying of 9, retrieval of past decomposition of 39 = 22 + 17, special decomposition of 17 into 9 + 8, keying of 9, keying of 8 and retrieval of past decomposition of 67 = 39 + 28, calculation of 16 as part of 28, calculation of 12 as the other part, special decomposition of 16 into 9 + 7, keying of 9, keying of 7 and retrieval of past decomposition 28 = 16 + 12, special decomposition of 12 into 7 + 5, keying of 7, keying of 5 and processing the end of the trial.