“…For example, several scholars argue that the cognitive mechanisms underlying metacognition and those necessary for monitoring the mental states of others are dependent on one another in some manner (Carruthers, 2009; Frith & Happé, 1999; Goldman, 2006). Although it is still unclear whether any animals possess the full set of theory of mind abilities that humans possess (see reviews in Apperly, 2010; Bräuer, 2014; Call & Tomasello, 2008; Emery & Clayton, 2009), nonhuman primates, dogs, and scrub jays all demonstrate an ability to track the perceptual access and knowledge of other agents, which is one component of what researchers have referred to as a theory of mind (nonhuman primates: Flombaum & Santos, 2005; Hare, Call, & Tomasello, 2001; Kaminski, Call, & Tomasello, 2008; Marticorena, Ruiz, Mukerji, Goddu, & Santos, 2011; Santos, Nissen, & Ferrugia, 2006; Schmelz, Call, & Tomasello, 2011; scrub jays: Dally, Emery, & Clayton, 2004, 2005, 2006; Emery & Clayton, 2001; domesticated dogs: Bräuer et al, 2004; Call, Bräuer, Kaminski, & Tomasello, 2003; Catala, Mang, Wallis, & Huber, 2017; Cooper et al, 2003; Johnston, Huang, & Santos, 2018; Kaminski, Bräuer, Call, & Tomasello, 2009; Kaminski, Pitsch, & Tomasello, 2013; Maginnity & Grace, 2014; Topál, Miklósi, & Manyik, 2004). Therefore, it is notable that, prior to the findings of the current study, the species that seem to think about and act upon the knowledge of others also show similar aptitude when thinking about and acting on their own knowledge.…”