Humans have been called “the symbolic species” because they are capable of grasping abstract symbolic patterns that could be generalized to a broad range of novel stimuli. This capacity is most evident in the domain of language learning, as well as in mathematics and music, where human cognition is vastly more developed than that of other primates. It is often proposed that language faculty reflects a broader human-specific ability to acquire and represent recursive structures or regular combinations of symbols. Searching for comparative evidence on the neural representation of rules and symbols may therefore shed light on the evolutionary origin of human-specific cognition.