The publicity frenzy over Paul the octopus, who accurately predicted the results of the World Cup by opening boxes labelled with team colours, has concealed something much more interesting than his apparent psychic powers. Here is an animal with a third of his nervous system outside his brain and no central spinal column who is nevertheless able to open man-made jars and boxes. This ‘lower form of life’, as we might once have called an invertebrate, can use tools, navigate mazes, recognise the humans that feed him, and make use of landmarks in planning a route.
Scientific interest in octopus intelligence is part of a quiet revolution in animal behaviour science. For generations, those studying animals were either ethologists, busy noting instinctive behaviour patterns in wild animals, or behaviourists, putting rats and pigeons into little boxes and studying how they responded either to punishing electric shocks or food pellet rewards.
Ethologists and behaviourists argued that animals did not have thoughts or feelings or, if they did, these were no concern of science. What could not be known ought not to be studied. To suggest otherwise was to commit the grave scientific sin of anthropomorphism. One of the most famous behaviourists, B.F. Skinner, inventor of the Skinner box for rats and pigeons, went so far as to claim that emotions were ‘excellent examples of the fictional causes to which we commonly attribute behaviour’.
Today, work with apes, elephants, dolphins and even octopuses like Paul suggests that animals are much cleverer than we thought — and they probably have feelings of joy and fear and anger much like we do. Some may even be self-aware. Moreover these animals, like human beings, have distinct personalities.
Zoo curators have long known that octopuses are exceptional escape artists, likely to crawl out of their tanks if water conditions inside are poor. Octopuses have even been known to leave their tanks, crawl to tanks nearby to find some other living creature to eat, and then crawl home again. As evolution could hardly have wired in the instinct to escape from tanks, it seems as if this might be evidence of octopus intelligence.
Exactly how clever they are is still not known. There is a much used, if controversial test called the mirror self-recognition test, whereby a spot is painted on an animal’s body (usually on the face where the animal itself cannot see it) and the animal is put in front of a mirror. If the animal starts touching this spot, this means it has recognised its own image in the mirror. If not, it probably thinks the image is another animal.
Mirror self-recognition is meant to be evidence of what is called theory of mind, or self-awareness, hitherto thought to exist solely among Homo sapiens. Children under the age of 18 months do not recognise themselves in a mirror, neither do most animals. Yet great apes, elephants, dolphins, killer whales and possibly magpies do. Octopuses, though they change colour when they see their image in the mirror, fail to show self-recognition.
An intriguing discovery, however, was that octopuses could play. When octopus experts Jennifer Mather and Roland Anderson put a floating jar in the tank of ten octopuses, two of them started playing with it. They aimed jets of water at the jar, moving it towards the tank water flow current, which shot it out again into the tank. They were playing with the jar rather like a child bounces a ball against a wall. Moreover, octopuses have been filmed using coconut shells as shields, a good example of tool-use.
So do octopuses feel joy and fear and anger like we do? Possibly they do. Octopuses and their relatives the squids change their skin colours and patterns when they feel alarmed. Squids, for instance, will flash white at each other during a male vs male contest. The octopuses placed in front of a mirror responded with changing skin patterns and colour, though it is not clear what this meant.
Neuroscientists who study the workings of the brain have not yet turned their attention to octopuses, but they have looked extensively at animals like rats. Jaak Panksepp, a neuroscientist who has spent years studying what goes on in the brain, certainly believes that animals experience emotions and share many of these emotions with us humans. It is Panksepp who has put forward the hypothesis that the emotional joy of play, shown in both young rats and human children, is embedded in the brain’s operating systems. This may also apply to the young octopuses playing with the floating jar.
Other scientists are examining the possibility that animals feel not just basic emotions such as joy, anger, fear and love, but also the more complex emotions of jealousy, guilt and shame. These are emotions that suggest some level of self-awareness and are usually thought to be experienced only by humans. However, studies by psychologist Dr Paul Morris and colleagues at Portsmouth University suggest that domestic animals, like dogs and cats, do display complex emotions such as jealousy.
Octopuses even seem to have different individual personalities, like human beings do. When the scientists at Seattle Aquarium tested baby octopuses for temperament, and then tested them again later in life, they found that individuals differed one from another, and that this individuality persisted into later life. So like each of us, every octopus is a special individual with different ways of behaving.
In fact, many animals seem to have personality traits not unlike human ones. Professor Samuel D. Gosling of the University of California has suggested that the temperamental differences between individual octopuses look remarkably like the extroversion/introversion and neuroticism/emotional stability traits that are found in humans. ‘The human scoring low on Extroversion stays at home on Saturday night… the octopus scoring low on Boldness stays in its protective den during feedings…’, he wrote.
If even octopuses can solve problems, feel some of the same emotions as we do, and have the same kind of personality traits, where does that leave the sin of anthropomorphism? ‘A lot of what we thought was uniquely human is not so,’ says Morris. ‘For instance, it cannot be anthropomorphic to call animals angry or sad. An irony is that Darwin’s big message was the continuity of mind across species.’
Indeed, Darwin wrote: ‘The fact that the lower animals are excited by the same emotions as ourselves is so well-established that it will not be necessary to weary the reader by many details.’ It is amazing that a century and a half later his scientific successors are only just coming to terms with the similarities between humans and animals — even more amazing than an octopus called Paul picking Spain as the World Cup winner.