Psychol. Res. 42, 135--155 (1980) ical (Wundt Centennial Issue) © by Springer-Verlag- 1980 Wilhelm Wundt's Psychology of Memory Eckart Scheerer Universitiit Oldenburg, Federal Republic of Germany Summary. The work of Wilhelm Wundt and his students in the psychology of memory is reviewed. Wundt rarely used the concept 'memory', but he dealt extensively with a number of problems that today are often discussed under the heading of 'memory'. Four components of his theory are distinguished and traced through the successive stages of the evolution of the theory: the theory of dispositions, the concept of the memory image, the revised doctrine of associations, and the taxonomy of recognition and recollection. The experi- mental work of the Leipzig laboratory is reviewed as it relates to the conceptu- al framework developed by Wundt. Some implications of the Wundtian per- spective for modern cognitive psychology are outlined. Introduction The psychology of memory belongs to the least known aspects of Wilhelm Wundt's psychology. In his classic History of Experimental Psychology Boring closes his brief account of the relevant work of the Leipzig laboratory with the comment that these studies 'made little impression as compared with the effective research upon memory by Ebbinghaus and G.E. Miiller' (Boring 1957, p 343). Boring's account is correct insofar as the 'Verbal Learning' perspective prevalent until the sixties of our century indeed may be traced to the Ebbinghaus - G.E. Miiller - Meumann tradition. Never- theless, Wundt has dealt extensively with a number of problems that today would be treated under the heading of memory. Because his views should be more attractive to the modern 'cognitivist' trend in memory research than those of the rival 'Verbal Learning' theorists, it is perhaps a useful enterprise to unearth the Wundtian tradition of memory research. There is one simple reason why the Wundtian psychology of memory should have escaped the attention of many psychologists: it was not presented under the heading Send offprint requests to: Eckart Scheerer, Universit~it Oldenburg, FB 1 - Psychologie, Birkenweg 3, D-2900 Oldenburg, Federal Republic of Germany 0340--0727/80/0042/013 5/~ 0.420 136 E. Scheerer 'memory'. Wundt had little use for the term 'memory'; he felt that it was a remnant of the old faculty psychology, which in turn had derived it from the pre-scientific psychology of common sense (1920, p 300). According to Wundt, the concept of memory, as it is usually employed, refers to the 'general ability for the renewal of ideas' (1887, p 394), and thus it carries the misleading implication that ideas are substance-like entities waiting for their renewal. However, Wundt conceded that the term had a certain limited usefulness. It may serve as a 'shorthand expression for certain highly complex products of association and of active apperception'; it is needed by descriptive psychology in the classification of individual differences (1887, p 394); and finally, it finds its place in the practical applications of psychology, primarily in education (1909, pp 14 f). Accordingly, Wundt treated memory, together with imagination and intelligence, in a special chapter of the Grundziige der physiolo- giscben Psychologie which was entitled, from the second to the fourth edition, 'Mental Endowments' (Geistige Anlagen), and afterwards, 'Complex Intellectual Functions'. This chapter was reserved, in the earlier editions, for certain individual differences in memory abilities along with some sentences on the development of memory and its decay in old age. In the later editions, the 'learning experiments' performed by Ebbinghaus, G.E. Miiller and others received a brief and rather cool review in this chapter. Components of Memory in the Context of Wundt's Psychology Where, then, should we look for Wundt's own psychology of memory? The answer to this question depends on what we ourselves want to mean by 'memory', and how well we can adapt our own conception to that of Wundt. I propose to take as a starting-point the following distinction between various memory components which has gained considerable popularity in recent memory research: a) Iconic (in the visual case) or Echoic (in the auditory case) Memory, a short-lasting after-effect of sensory stimulation; b) Working Memory, concerned with the storage and processing of inter- mediary results in all types of mental activities; c) Episodic Memory, dealing with personal or autobiographical memories that are localized with respect to a context defined by the internal temporal dimension of our own experience; d) Semantic Memory, our individually acquired but impersonal and de-contextualized 'knowledge of the world'. Although Wundt had something to say about all of these four memory components, he did not apply the label 'memory' to all of them. Despite his criticism of the 'vulgar' concept of memory, he was careful to keep to its definition when using it. Because the concept referred to the renewal of ideas, it could not be applied when some con- scious phenomenon or process was extended over time without having vanished from consciousness, as is the case in the 'storage' processes nowadays called Iconic/Echoic and Working Memory. 'Iconic' Memory and the Positive After-Image In his discusssion of Erdmann and Dodge's (1898) tachistoscopic experiments on word recognition, Wundt (1900 a) pointed out that the effective duration of the image (reale Bildzeit) of a tachistoscopic stimulus could be much longer than its nominal Wilhelm Wundt's Psychology of Memory 137 exposure time, and his estimate of the duration of the reale Bildzeit was close to modern estimates of ionic storage (250 ms). Although Sperling (1960) drew the inspiration for his pioneering experiments on brief visual storage in part from Wundt, it may be doubted that Wundt's views had much in common with the modern concep- tion of iconic storage as found in Averbach and Sperling (1961) and Neisser (1967). To be sure, Wundt felt that a spatial shift of attention (Aufmerksamkeitswanderung) could occur during the after-duration of a tachistoscopic stimulus, and this idea has some similarity to the notion of scanning as employed by modern authors (e.g., Neisser 1967). But on the whole Wundt was far from assigning any particular func- tional significance to the persistence of briefly exposed stimuli. He conceptualized it in terms of a positive after-image of retinal origin, i.e., as a direct expression of the persistence of neural excitation (1908/11, Vol II, p 202). The presence of positive after-images was a nuisance rather than an asset to the reading process, because they would superimpose on each other and thus prevent the intake of information during eye-movements (1908/11, Vol III, p 583). In brief, Wundt's treatment of 'storage' phenomena in tachistoscopic viewing is much more congenial to recent views that stress the retinal origin and artifactual nature of 'iconic memory. (Turvey 1977; Neisser 1976; Sakitt 1976), than to the 'received view' tracing its origin to Averbach and Sperling and to Neisser (1967). 'Working'Memory and tbe Span of Consciousness I have found only one place where Wundt refers to the immediate recall of a memory list as the 'marginal case of a memory achievement' (1908/11, Vol III, p 559). On the whole, he prefers to deal with the processes involved in short-term (or rather, working) memory under the rubrics of 'span of consciousness' (Bewusstseinsumfang) and 'focus of attention' (Fokus der Aufmerksamkeit). The spans of attention and of consciousness belong to the cornerstones of Wundt's psychological system and have been discussed recently by Leahey (1979); I therefore restrict my exposition to their significance for the psychology of memory. Wundt preferred to use a visual metaphor when talking about the relationship between attention and consciousness, but this should not distract us from the fact that he extended his theorizing to the case of audi- tion and to the processing of successive stimuli. In fact, the original experimental paradigm for the measurement of the spans of attention and consciousness involved the same/different judgment about two successively presented sequences of metro- nome beats. The length of the sequences about which an immediate judgment of identity could be given depended on whether or not some rhythm could be imposed on the sequence: without a rhythm, sequences containing up to six elements could be apprehended immediately (span of attention), while with rhythmical sequences the number of elements occasionally rose to 40 (span of consciousness). For Wundt there was no basic difference between simultaneously and successively presented elements: in both cases the upper limit of performance depended on the number of separate im- pressions that could be merged into one 'comprehensive idea' (Gesamtvorstellung). The apprehension of sequentially organized input (e.g., speech perception) therefore always involves a transformation from succession to simultaneity, and the inverse transformation is obligatory in the production of sequentially organized output, as in speech production. Wundt's classical definition of the concept 'sentence' - 138 E. Scheerer the linguistic expression of the voluntary segmentation of a comprehensive idea into its components according to their logical relations (1900 b, Vol II, p 236) - presupposes the concept of the span of consciousness: The ability of people to think in sentences is closely connected with their span of consciousness; and it is an immediate consequence of this circumstance that all essential components of a sentence may be conscious in the moment we begin to utter a sentence (ibid., p 235). Another consequence of the function of attention and consciousness in speech produc- tion is that the modulation of speech according to volume, duration, and pitch is governed by the basically rhythmic nature of attention. At the end of the nineteenth century it became increasingly popular to refer to the phenomena covered by Wundt's term 'span of consciousness' in terms of memory (James's expression 'primary memory', borrowed from Exner).