The evolution of interdisciplinarity in five social sciences and humanities disciplines: relations to impact and disruptiveness

It is generally believed that the tide of interdisciplinarity is rising and becomes increasingly prevalent among various disciplines in natural and biomedical sciences. However, for the social sciences and humanities (SSH) limited evidence supports such a statement from bibliometric perspectives. Also, it has seldom been quantified how interdisciplinarity and its various aspects evolve over time. This paper analyzes the evolution of interdisciplinarity focusing on two aspects, namely process and outcomes, to draw a comprehensive trajectory of interdisciplinarity for five SSH disciplines over 50 years. We find that research in each of these five SSH disciplines is broadening its knowledge base by involving more disciplines yet is at the same time shifting towards further specialization. Interdisciplinarity is found to be positively correlated with citation impact and visibility and becomes stronger as the citation window widens up. The disruptiveness of publications, however, is negatively correlated with the level of interdisciplinarity and increasingly so over time.