Unpredictable animals: individual differences in intraindividual variability (IIV)

► Intraindividual variability (IIV) refers to short-term, unpredictable intraindividual fluctuations in behaviour. ► Psychologists have shown that IIV in humans is not 'random noise'. ► Current statistical models assume that IIV does not vary across individuals. ► Our results show that IIV significantly varies across individuals in hermit crabs and damselfish.