Have you heard of the Big Five personality traits in humans? In humans, psychologists have identified varying degrees of openness, conscientiousness, extraversion, agreeableness, and neuroticism. Now, animal cognition researchers have found five personality factors in chimpanzees that seem suspiciously similar to those found in humans.

Individual chimps differ in conscientiousness, dominance, extraversion, agreeableness and intellect. Sound familiar? Chimpanzees have long been known to be our close relatives, but this research reveals that they are individually variable, just like us. Some chimps are agreeable extroverts, while others might be grumpy introverts.

Further, many chimp personality traits correlate significantly with a neuropeptide, suggesting that there is a neurobiological basis for personality.

How is personality studied and quantified in animal cognition research? In short, "personality" is the consistency of behavioural responses, across situations. So, a dominant and conscientious chimp will tend to be dominant and conscientious in most situations. In this study, personality was measured via questionnaires completed by the chimpanzee's caregivers. In other, similar, studies, personality is measured directly by experimental manipulation and recording animals' responses. (These methodological differences are currently being debated and discussed amongst behavioural ecologists).

The new field of personality research breaks down animal cognition to a new, finer level; now, we are looking at individual variation in behaviour and cognition within a single species. This is of crucial importance to understanding how cognitive and behavioural traits arise in different species, for two reasons. First, individual variation leads to differential fitness, which leads to evolution by natural selection! Second, the fact that there are different (and common) personality types among chimpanzees implies that there is more than one "winning personality." For example, many chimps are dominant and undercontrolled ("Alphas"), but it also common to observe chimps that are playful and sociable ("Betas"). Both Alphas and Betas are successful from an evolutionary standpoint!

So if you are worried that you'll never make it in today's job market because you don't have the traits of an Alpha (you're too sociable and easy-going, say), don't worry! Beta chimpanzees make it, too-- and the stakes are much higher for our furry cousins. In the wild, personality could be the difference between life and death.