  We analyze the publication records of individual scientists, aiming to
quantify the topic switching dynamics of scientists and its influence. For each
scientist, the relations among her publications are characterized via shared
references. We find that the co-citing network of the papers of a scientist
exhibits a clear community structure where each major community represents a
research topic. Our analysis suggests that scientists tend to have a narrow
distribution of the number of topics. However, researchers nowadays switch more
frequently between topics than those in the early days. We also find that high
switching probability in early career (<12y) is associated with low overall
productivity, while it is correlated with high overall productivity in latter
career. Interestingly, the average citation per paper, however, is in all
career stages negatively correlated with the switching probability. We propose
a model with exploitation and exploration mechanisms that can explain the main
observed features.
