Effects of sorting on subsequent recall of unrelated items: a developmental study.

Second graders, fifth graders, and adults participated in 2 experiments designed to study the effects of sorting on subsequent recall of unrelated words. 1 group sorted the items freely, while a second group was constrained to learn the sorting schemes generated by free subjects. In the first experiment, subjects sorted until they reached a criterion of organizational stability. In Experiment 2, sorting was terminated prior to reaching a stable criterion. Recall and output clustering were reduced in Experiment 2, relative to Experiment 1, because of organizational instability. No meaningful differences were found in either experiment in the sorting schemes generated by free subjects in the 3 age groups, nor was there an effect of age of yoking partner on performance of constrained subjects. This result differed from previous research, and it was concluded that the sorting technique diminished differences in organizational behavior usually found between older and younger subjects.     

Recent progress in the plastic methods of structural analysis

The techniques described in Part I of this paper for the calculation of plastic failure loads under proportional loading are further exemplified by indicating solutions for a rectangular building frame, a Vierendeel girder, and a shed-type portal frame. A method for estimating deflections of a frame just as the collapse load is attained is then described, with some indications as to its reliability. More general conditions of loading than proportional loading are next discussed, and generalized load and failure concepts are defined. The theorems and techniques for determining critical shakedown loads under variable, repeated loading are then described and illustrated. The relation of the elastic-plastic shakedown analysis to the much simpler analysis for failure under single load applications is discussed.