Octopuses that reacted to one film aggressively tended to respond to all films on a particularly day in the same way. But over longer periods of time, any trace of “personality” or consistency evaporated. They might react aggressively one day, but much less so on another day. “It’s a bit of a surprise,” says Hanlon. Other cephalopods, such as the dumpling squid, display consistent personalities for most of their lives.
This lack of consistent behaviour may be related to octopuses’s huge brain size, relative to other cephalopods. Big brains may “afford octopuses considerable behavioural flexibility that allows them to change their behaviour adaptively over time,” write the researchers.
This definition of “personality” is a very interestingly stupid one. It ties something that sounds like a deeply innate complex of behavioral traits to whether the researcher can figure out a set of simply stimuli that will elicit the same behavior day after day.