TL;DR: Organization theory as mentioned in this paper proposes that human memory is organized, instead, in a nested, hierarchical fashion that structures storage and retrieval, and that there is a limit of four expandable units in organized memory and that the same limit is found in recall and production units.
Abstract: Recent as well as historical critiques of association theory, which is based on automatic linking mechanisms, lead to a consideration of an alternative: organization theory. The latter theory postulates that human memory is organized, instead, in a nested, hierarchical fashion that structures storage and retrieval. Organization theory also postulates that there is a limit of four expandable units in organized memory and that the same limit is found in recall and production units.
TL;DR: Ebbinghaus's major contribution as a theorist was to accomplish the transition from the first level to the second, and the analysis of serial learning in terms of his conception of multiple types of associations may prove to have greater generality than has yet been realized.
Abstract: Three levels of association theory are distinguished: (a) empirical laws relating operationally definable units; (b) theoretical concepts of association, supported by converging lines of evidence; and (c) theories assimilating concepts of association into more elaborate structures. These levels correspond roughly to stages in the evolution of association theory from the mid-19th century to the present. Ebbinghaus's major contribution as a theorist was to accomplish the transition from the first level to the second. The analysis of serial learning in terms of his conception of multiple types of associations may prove to have greater generality than has yet been realized. However, to account for many phenomena of practical and theoretical interest, this model requires augmentation by a control concept that provides a basis for organization beyond serial linkages of units.