COGNITIVE PSYCHOLOGY 6, 421435 ( 1974) Serial Learning: Identification of Subjective

Learning of fixed arbitrary sequences proceeds by idiosyncratic sub-sequencing and assembly of the resulting subsequences. An error item that just precedes a subjective subsequence is a closely constrained member of that subsequence. Identification and characterization of subjective sub-sequences were accomplished by analyses of forward serial learning, free recall, and backward serial learning. We conclude that ordinary serial learning cannot be represented by traditional continuous-process theories, but instead must be treated by an organizational model. When it comes to learning a sequence of events, it is clear that subjects make use of organizational principles provided by the experimenter. Thus, for example, McLean and Gregg (1967) divided a randomly ordered list of 24 letters into groups and observed differential within- and be-tween-group interresponse times both on the criterion trial of serial recall learning and in attempts to recall the list backwardly. Similarly, Wilkes and Kennedy (1970) induced certain groupings on lists of nine letters and observed lengthened reading times at group boundaries, as well as other boundary related phenomena. Also, Lesgold and Bower (1970) have shown that when a serial list of letters is grouped into letter triplets, learning errors predominate at the position of letters that initiate a triplet. The foregoing results exemplify the fact that subjects respond to ex-perimenter-determined subdivision of otherwise arbitrary sequences in a serial learning task. A useful representation of such results is that events within a group are serially organized together under a representative implicit code, that these codes are themselves grouped together in some fashion, and so on to yield a hierarchical memory structure for th