Rhesus monkeys have an interoceptive sense of their beating hearts

Significance The capacity to sense interoceptive signals is thought to be fundamental to broad functions including, but not limited to, homeostasis and the experience of the self. While neuroanatomical evidence suggests that nonhuman animals—namely, nonhuman primates—may possess features necessary for interoceptive processing in a way that is similar to humans, behavioral evidence of this capacity is slim. We presented macaques with audiovisual stimuli that were either synchronous or asynchronous with their heartbeat and demonstrated that they view asynchronous stimuli, whether faster or slower, for a significantly longer period than they do synchronous stimuli.