  Current phylogenetic comparative methods generally employ the
Ornstein-Uhlenbeck(OU) process for modeling trait evolution. Being able of
tracking the optimum of a trait within a group of related species, the OU
process provides information about the stabilizing selection where the
population mean adopts a particular trait value. The optima of a trait may
follow certain stochastic dynamics along the evolutionary history. In this
paper, we extend the current framework by adopting a rate of evolution which
behave according to pertinent stochastic dynamics. The novel model is applied
to analyze about 225 datasets collected from the existing literature. Results
validate that the new framework provides a better fit for the majority of these
datasets.
