 The researchers examined the effects of simpetry on the evolution of cognition in frugivorous primates. They traced the evolutionary history of simpetry between two groups of frugivorous primates and then fit phylogenetic models to determine how simpetry affected the evolution of certain brain regions. The results showed that simpetry had no effect on the evolution of the whole brain or brain regions involved in immediate information processing but did have an effect on the evolution of brain regions associated with long-term memory of interactions with the socio-ecological environment. Simpetry was also linked to slower rates of primate speciation. This article was authored by Robira, Benjamin, and Peresla Mark, Benoit.