ABSTRACT
In the past 50 years, there has been a plethora of studies on the capacity for mirror self-recognition (MSR) as measured by the mark test in nonhuman animals, specifically primates. Evidence over this period of time has consistently reported MSR abilities in chimpanzees and, to a lesser extent other great apes; however, within chimpanzee samples, there are considerable individual differences in the number of individuals that pass or fail the mark test. In this chapter, I present data from my laboratory on individual differences in MSR abilities and discuss the impact of different subject variables on performance. I also present data on the cognitive and neuroanatomical correlates of individual variation in MSR in chimpanzees. The collective findings are discussed within the context of evolutionary theories on the origin of MSR abilities in primates.
