ABSTRACT
Few things matter more than the mental states of those nearby. Their ignorance defines limits on cooperation and presents opportunities to exploit in competition. (If she’s seen where you stashed those mealworms she’ll pilfer them when you’re gone, leaving you without breakfast. And you won’t get that grape if he hears you sneaking past.) What others feel, see and know can also provide information about events otherwise beyond your ken. It’s no surprise, then, that abilities to track others’ mental states are widespread. Many animals, including scrub jays (Clayton, Dally and Emery 2007), ravens (Bugnyar, Reber and Buckner 2016), goats (Kaminski, Call and Tomasello 2006), dogs (Kaminski et al. 2009), ring-tailed lemurs (Sandel, MacLean and Hare 2011), monkeys (Hattori, Kuroshima and Fujita 2009) and chimpanzees (Karg et al. 2015), reliably vary their actions in ways that are appropriate given facts about another’s mental states. What underpins such abilities to track others’ mental states?
