From The New York Times:
Scientists are not typically disposed to wielding a word like “personality” when talking about animals. Doing so borders on the scientific heresy of anthropomorphism. And yet for a growing number of researchers from a broad range of disciplines – psychology, evolutionary biology and ecology, animal behavior and welfare – it is becoming increasingly difficult to avoid that term when trying to describe the variety of behaviors that they are now observing in an equally broad and expanding array of creatures, everything from nonhuman primates to hyenas and numerous species of birds to water striders and stickleback fish and, of course, giant Pacific octopuses.
Through close and repeated observations of different species in a variety of group settings and circumstances, scientists are finding that our own behavioral traits exist in varying degrees and dimensions among creatures across all the branches of life’s tree. Observing our fellow humans, we all recognize the daredevil versus the more cautious, risk-averse type; the aggressive bully as opposed to the meek victim; the sensitive, reactive individual versus the more straight-ahead, proactive sort, fairly oblivious to the various subtle signals of his surroundings. We wouldn’t have expected to meet all of them, however, in everything from farm animals and birds to fish and insects and spiders. But more and more now, we are recognizing ourselves and our ways to be recapitulations of the rest of biology. And as scientists track these phenomena, they are also beginning to unravel such core mysteries as the bioevolutionary underpinnings of personality, both animal and human; the dynamic interplay between genes and environment in the expression of various personality traits; and why it is that nature invented such a thing as personality in the first place.