A prominent feature of late nineteenth-century psychology was its intense preoccupation with precision. Precision was at once an ideal and an argument: the quest for precision helped psychology to establish its status as a mature science, sharing a characteristic concern with the natural sciences. We will analyse how psychologists set out to produce precision in 'mental chronometry', the measurement of the duration of psychological processes. In his Leipzig laboratory, Wundt inaugurated an elaborate research programme on mental chronometry. We will look (...) at the problem of calibration of experimental apparatus and will describe the intricate material, literary, and social technologies involved in the manufacture of precision. First, we shall discuss some of the technical problems involved in the measurement of ever shorter time-spans. Next, the Cattell-Berger experiments will help us to argue against the received view that all the precision went into the hardware, and practically none into the social organization of experimentation. Experimenters made deliberate efforts to bring themselves and their subjects under a regime of control and calibration similar to that which reigned over the experimental machinery. In Leipzig psychology, the particular blend of material and social technology resulted in a specific object of study: the generalized mind. We will then show that the distribution of precision in experimental psychology outside Leipzig demanded a concerted effort of instruments, texts, and people. It will appear that the forceful attempts to produce precision and uniformity had some rather paradoxical consequences. (shrink)

Illustrations played an important role in the articulation of Wundt’s experimental program. Focusing on the woodcuts of apparatus and experimental designs in the six editions of his Grundzüge der physiologischen Psychologie (published between 1873 and 1911), we investigate the uses and functions of illustrations in the experimental culture of the physiological and psychological sciences. We will first present some statistics on the increasing number of illustrations Wundt included in each new edition of his handbook. Next we will show how Wundt (...) managed to introduce the material and literary technologies of physiology into the ‘new psychology’. The distribution of Wundt’s material technology will be further demonstrated by highlighting the crucial role of technicians and instrument-makers. We will use Shapin and Schaffer’s notions of the ‘three technologies’ and ‘virtual witnessing’, combined with Latour’s concept of ‘immutable mobiles’, as analytical tools to explore the strategic aspects of Wundt’s illustrations. (shrink)