Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Octopuses have always amazed the world with their intelligent behavior, unique colorations to adapt to the background, and the way they manage their flexible arms without getting them entangled. The octopus is an example of advanced cognitive adaptation, but how its brain (see the yellow part in picture below) works still remains a mystery. The octopus brain does not look at all like brains of other animals. Is has a huge optic lobe underneath their eyes and a highly developed touch system which explains their excellent eye sight and sense of touch. It has two memory systems that follow these two sensory systems: a visual and an tactile memory used to identify signals in the environment for attack or retreat. And to explore novel situations. Anatomy of the octopus But most amazing is how the octopus controls its eight arms. Its nervous system contains 500 million neurons. But two-thirds of these nerve cells are located in the nerve cords of its arms (see yellow extensions in picture), which makes the eight tentacles function as an extended brain. The central brain only has to trigger a command to the arms, which then carry out the full action sequence. Suggesting that the entire movement plan is embedded in the arm itself and not in the central brain like in mammals. There is no proprioception, that is neural feedback paths of their movements to the brain, so movements must be monitored by 'seeing what happens' Octopus evolution Peter Godfrey-Smith a philosopher of science and experienced scuba diver became fascinated by the octopus and expressed some interesting views on this creature in his recent and captivating book*. Why has the octopus followed such a strange route of evolution, completely different from that of birds and mammals? Cephalopods, the family to which the octopus belongs have a history of half a billion year of evolution. Their ancestor started as a mollusk that gradually transformed itself via various stages into the three common species of today’s world: the Nautilus, the Cuttlefish and the Octopus. The early species lived on the seafloor, later came development of the arms to lift themselves from the seafloor. Camerosceras is one of the spectacular intermediate stages; this was a large predatory cephalopod with an estimated length of 18 feet (see figure below). Early now extinct versions still had shells but newer forms gave op their shells, with Nautilus as an exception. Some important steps in the the evolution of the cephalopods (adapted from Peter Godfrey-Smith (2016)).* An amazing fact of the octopus is that this smart and complex creature has no skeleton and hard parts at all. This allows it to change the form and size of its body, for example to squeeze itself through narrow holes of only a few centimeters wide. As said earlier, unlike brains of vertebrates the octopus has no central brain that controls the limbs. The octopus arms are in fact its brain. A term used by some scientists is embodied cognition: our body itself is responsible, rather than our brain, for some of the smartness with which we handle the world.** This raises the question of consciousness, that bugged the mind of philosophers since ancient times, and who believe that consciousness is uniquely human. Unlike many philosophers modern scientists take an different point of view. For example primate biologist Frans de Waal of the Yerkes Institute believes that intelligence and consciousness are not uniquely tied to humans. So does diver-philosopher Godfrey-Smith who poses the question: what about consciousness in the octopus? Since its arms are its brain but alto also its agents or instruments, the octopus must be in a sort of hybrid situation. Its arms are partly self but also partly non-self: agents of their own. Octopus intelligence Perhaps animal intelligence and consciousness become less of a puzzle if we accept that intelligent behavior evolved in man as well as animal in different forms dependent on the demands of their specific environments. Think of the tree of life with a common ancestor but with various branches leading to unique and clever adaptations of even non-mammalian species. In the octopus intelligence is largely a ‘grasp, explore and sense’ intelligence. They do not use their intelligence for maintaining complex social interactions like humans and chimpanzees. But they do have a highly exploratory and opportunistic style of interaction in their watery environment. Octopi are clever, not because they share a common ancestor with mammals and humans, but because they followed a completely separate evolutionary branch than ours. So genetically, meeting an octopus is indeed like meeting an intelligent alien. Octopi held in captivity have the reputation of mischief and escape. They have been seen to escape from their own aquarium, to walk around on the floor of the room en and even to visit a neighboring tank for food. There is even the story of an octopus squirting jets of waters against a lamp short circuiting the power supply, or against visitors of its tank! These anecdotes suggest that the octopus may adapt easily to its environment and even its human keepers. Unlike fishes they seem to have developed a sense that they are inside, and their visitor outside the tank. They are also able to use new objects for their safety. In 2009 researchers in Indonesia were amazed to see octopi carrying around half coconut shells over the sea floor to use as portable shelters. Octopuses in the sea are also known to use their arms in battles, by hurling sand and debris to its rivals. Getting to know the octopus makes it hard to accept that this superb creature is still hunted down to end up in sea food dishes all over the world. Sources and links J. Z. Young. "The Anatomy of the Nervous System of Octopus Vulgaris" Oxford University Press. N.Y. (1971) *Peter Godfrey-Smith. Harper. Other Minds. The octopus and the evolution of intelligent life. Collins Publisher.London (2016) **Hillal Chiel and Randall Beer (1997). The Brain has a a Body: Adaptive Behavior Emerges fro Interavtions of Nervous System, Body and Enviroment. Trens in Neroscinec 23 (1997):553:57 http://cephalove.blogspot.nl/2010/06/view-of-octopus-brain.html http://www.dailymail.co.uk/sciencetech/article-3214442/Octopuses-fire-Cephalopods-seenhurl-shells-debris-rivals-fights-protect-territory.html