Folding a fish, making a mushroom: the role of diagrams in executing assembly procedures.

Three experiments examined the role of step-by-step and final-state diagrams in supporting object assembly. A total of 180 college students made origami objects from instructions consisting of text only, text plus a final-state (completed-object) diagram, or text plus step-by-step and final-state diagrams. In Experiments 1 and 2, construction accuracy in the final-diagram condition was comparable to that in the step-by-step condition when the objects required few assembly steps, but it was comparable to that in the text-only condition when many steps were required. Experiment 3 independently manipulated the number of assembly steps and the ease of seeing the steps in, or inferring them from, the final diagram. The results indicated that the case of extracting the steps from the final diagram was the primary causal variable in the interaction with instructional condition. We interpret these results in terms of mental model construction and working memory load.