Emory University primatologist Frans de Waal, who has studied mirror self-recognition
in mammals, called the findings "interesting and provocative."
Alexandra Horowitz, the research's leader, wrote in her report: "While domestic dogs, Canis familiaris, have been found to be skillful at social cognitive tasks and even some metacognitive tasks, they have not passed the test of mirror self-recognition
Furthermore, there is a lack of direct empirical evidences that support the association between the mirror self-recognition and a theory of mind (Nielsen & Dissanayake, 2004).
Based on her investigations, using the lipstick procedure in many cultures, the author concludes that the mirror self-recognition test is the best measure for self-referential behavior, and an indicator of self construction.
"It has long been realized that dolphins rank among the most intelligent mammals, and they can do many things that great apes can do such as mirror self-recognition
, communication, mimicry, and cultural transmission," Discovery news quoted Michael McGowen, lead author of the study, as saying.
Some elephants exhibit mirror self-recognition
The failure of monkeys to "pass" the well-known mirror self-recognition test has fostered the belief that these animals have no concept of self.
While the veracity of that conclusion can be debated (failure at mirror self-recognition needn't mean lack of self-awareness), a recent study of macaques suggests that monkeys understand other beings as agents with their own perspectives and intentions.
Studies of mirror self-recognition
(MSR) confirm that, "by 4 months of age, infants showed signs of self-other discrimination in specular images" (Rochat and Striano 42), but intriguingly, a 2003 study by Mark Nielsen, Cheryl Dissanayake, and Yoshi Kashima also showed that "prior to the second year (i.e., before the onset of MSR) infants prefer to look at images depicting the faces of same-aged peers rather than images depicting their own faces" (214)--that is, at faces like the ones in these baby books.
tests, which involve marking an animal with a spot that can be inspected or touched only by looking in a mirror, can be tricky to interpret, Pepperberg adds.
Previous research had shown that rhesus monkeys consistently failed in the mirror self-recognition
test, an important test of self-awareness, but like apes and dolphins, they did seem to possess the ability to monitor their own mental states.
These include mirror self-recognition
, cultural learning, comprehension of symbol-based communication systems, and an understanding of abstract concepts.