Clark, H. J. (1965). Recognition memory for random shapes as a function of complexity, association value, and delay. Journal of Experimental Psychology, 69(6), 590-595.

12 groups of 24 Ss each were examined on 2 tests at 3 delays or recognition accuracy of random shapes having 2 levels of complexity and 2 levels of association value (A). A measure of form coding was also taken. Forms of high A were more accurately recognized than forms of low A, and a 2nd recognition test on the same forms resulted in a practice effect for simple but not for complex forms. All delay effects were insignificant. Complex form coding was positively related to A. Simple form coding was infrequent and not related to A. Coding was positively related to recognition accuracy for complex forms only. Conclusions were: (a) Ss probably stored an uncoded image of the entire shape of simple, but not of complex forms; (b) complex forms were presumably remembered by making associations to them.