Using tricitation to dissect the citation image: Conrad Hal Waddington and the rise of evolutionary developmental biology

An authorʹs citation image is the set of authors with whom the author is cocited. When mapped using standard author cocitation analysis methods based on cited name co-occurrence counts across the entire citation database, the original context of cocitation (the focal author cocited with others) is lost. The citation image of Conrad Hal Waddington, a developmental biologist and evolutionary theorist, is mapped using both cocitation and tricitation approaches over three successive decades, 1975–1984, 1985–1994, and 1995–2004. All authors are tagged with a subject ID based on a principal components analysis of the cocitation data. The cocitation analyses place Waddington in a general subject context. The tricitation PFNets bring the major themes in articles citing Waddington into clearer focus. The changing scholarly landscape in which Waddingtonʹs work is used is demonstrated by changes in the citation image author set. These changes are associated with a shift from a primary focus on the mechanisms of evolutionary change (Waddingtonʹs work on canalization/genetic assimilation) to a resurgence of interest in Waddingtonʹs early experimental embryological work. The latter is linked to the emergence of evolutionary developmental biology, an interdisciplinary research area that examines the role of organismal development in evolutionary change.