It is widely known that certain cultural entities—known as “memes”—in a sense behave and evolve like genes, replicating by means of human imitation. A new scientific concept, for example, spreads and mutates when other scientists start using and refining the concept and cite it in their publications. Unlike genes, however, little is known about the characteristic properties of memes and their specific effects, despite their central importance in science and human culture in general. We show that memes in the form of words and phrases in scientific publications can be characterized and identified by a simple mathematical regularity.

We define a scientific meme as a short unit of text that is replicated in citing publications (“graphene” and “self-organized criticality” are two examples). We employ nearly 50 million digital publication records from the American Physical Society, PubMed Central, and the Web of Science in our analysis. To identify and characterize scientific memes, we define a meme score that consists of a propagation score—quantifying the degree to which a meme aligns with the citation graph—multiplied by the frequency of occurrence of the word or phrase. Our method does not require arbitrary thresholds or filters and does not depend on any linguistic or ontological knowledge. We show that the results of the meme score are consistent with expert opinion and align well with the scientific concepts described on Wikipedia. The top-ranking memes, furthermore, have interesting bursty time dynamics, illustrating that memes are continuously developing, propagating, and, in a sense, fighting for the attention of scientists.

Our results open up future research directions for studying memes in a comprehensive fashion, which could lead to new insights in fields as disparate as cultural evolution, innovation, information diffusion, and social media.