What allows for our human unique ability to jump into the minds of others? Synthesizing recent work in primate social cognition, I'll argue that humans possess a species-unique capacity to "mind-meld" an automatic mental state contagion that stems from our unique ability to represent the mental states of others. I'll first review work on emotional and behavioral contagion in non-human primates, suggesting that primates share our human capacity to automatically jump into other individuals' behavioral states. I'll then review my lab's studies on primate theory of mind. Using these results, I will argue that even though non-human primates can represent some aspects of other individuals' mental states, non-humans may lack the capacity to automatically represent others' mental states in the same way as humans do. In particular, I'll argue that humans have a tendency to automatically take on the mental states of others, and that this automatic tendency comes with a representational cost the act of representing others' beliefs, intentions, and preferences sometimes causes us to have less access to our own. I'll then discuss what this new empirical predictions this hypothesis provides for the field of social neuroscience.