A remarkable trend is emerging in major areas of psychological inquiry. The trend involves a renewed interest in mentalistic concepts, among which imagery and meaning are central. It is remarkable because such concepts, once prominent in psychology, became anathema in American psychology shortly after the turn of the century. The negative attitude is generally attributed to the behavioristic revolution, and the main issues and developments will be considered primarily in that context. However, in view of the attention given to human learning and memory in this book, it is important to note that the negative influence was not restricted to behaviorism proper, but stemmed also from the rote learning tradition established by Ebbinghaus in 1885. This approach was no less objective than Watson's behaviorism. Ebbinghaus abandoned the introspective method and sought to minimize effects attributable to pre-experimental associative habits and meaning (both mentalistic concepts in that prebehavioristic era) in order to reveal the factors responsible for the formation of new memory associations. The latter goal was to be achieved especially by the introduction of the nonsense syllable as the unit for the experimental study of memory. The main features of the Ebbinghaus approach persisted in rote learning experiments with little change for more than seventy years (see Irion, 1959).