The human ability to think abstractly may be unparalleled in the animal kingdom. Humans are one of only six species to pass the [[mirror test]] — which tests whether an animal recognizes its reflection as an image of itself — along with [[chimpanzees]], [[orangutan]]s, [[dolphin]]s, and possibly [[dove|pigeons]]<ref>Robert W. Allan explores a few of these experiments on his webpage: | The human ability to think abstractly may be unparalleled in the animal kingdom. Humans are one of only six species to pass the [[mirror test]] — which tests whether an animal recognizes its reflection as an image of itself — along with [[chimpanzees]], [[orangutan]]s, [[dolphin]]s, and possibly [[dove|pigeons]]<ref>Robert W. Allan explores a few of these experiments on his webpage: |