Anybody who has taken an undergraduate psychology course or filled out one of those online tests is probably familiar with the “big five” personality traits: openness, conscientiousness, extraversion, agreeableness and neuroticism. For example, if you identify with the statement “I talk to a lot of different people at parties,” you might score high on extraversion. An individual’s personality is thought to be fairly stable by adulthood, and the idea that it can be measured by just a handful of factors goes back at least a century.
But humans are not the only species whose personalities can be quantified along these lines; caregivers in zoos, sanctuaries and other captive environments commonly assess the personalities of animals, based on months or years spent observing and interacting with them. The specifics vary among species (for example, newts can be scored for their libidinousness and zebra finches and rhesus macaques for boldness), but the underlying notion that personality can be described by a small set of factors remains the same. Now research suggests that animals as widely divergent as chimpanzees and killer whales have surprisingly similar personality profiles.
Read the whole story: Scientific American