Are humans unique in having self-reflective consciousness? Or can precursors to this central form of human consciousness be found in non-human species? The Missing Link in Cognition brings together a diverse group of researchers who have been investigating this question from a variety of perspectives, including the extent to which non-human primates, and, indeed, young children, have consciousness, a sense of self, thought process, metacognitions, and representations. Some of the participants--Kitcher, Higgins, Nelson, and Tulving--argue that these types of cognitive abilities are...