How Did Early North American Clinical Psychologists Get Their First Personality Test? Carl Gustav Jung, the Zurich School of Psychiatry, and the Development of the “Word Association Test” (1898–1909)

Clinical psychology emerged in the United States during the first decades of the 20th century. Although they focused on intelligence tests, starting around 1905 certain clinical psychologists pursued personality assessment through a specific, nonintellectual kind of test: the word association test as devised by Swiss psychiatrist Carl Gustav Jung (1875–1961) at the Burghölzli psychiatric clinic in Zurich. The test was a key device in the professionalization of North American psychiatry and psychology during the early 20th century: from 1905 onward it was acknowledged, discussed, and applied by experimental and clinical psychologists. However, Jung’s original experiments and the development of the test itself have received only superficial or casual attention by historians of science. This article attempts to provide a critical, streamlined, and detailed account on the origin, development, and substance of the Zurich word association experiments. By drawing on heretofore overlooked primary sources, I offer a new, critical perspective on the emergence and development of Jung’s test while engaging with its main theoretical and methodological aspects. I show that the test was neither Jung’s sole creation nor did it consist of a simple, straightforward set of tasks. Contrarily, it was the result of a highly collaborative, multilayered institutionalized research program on linguistic and mental associations. The program, its data and its assumptions fueled several debates and data-driven discussions at Zurich, precluding the test from achieving a stable, standardized character.