A couple of weeks ago I wrote about cuttlefish [see ‘Wearing your heart on your sleeve‘ on January 16th, 2019] based on a wonderful book, that I was given for Christmas, called ‘Other Minds: The Octopus and the Evolution of Intelligent Life‘ by Peter Godfrey-Smith. Cuttlefish and octopuses are cephalopods that Peter Godfrey-Smith describes as ‘an island of mental complexity in the sea of invertebrate animals’. The most recent common ancestor of cephalopods and humans is so distant and was so simple that cephalopods represent an independent experiment in the evolution of large brains and complex behaviour. An octopus has about 500 million neurons, which is not as many as humans, we have about 100 billion; but still a large number and connectivity is probably more important than absolute size [see ‘Digital hive mind‘ on November 30th, 2016]. Whereas we have a central nervous system, an octopus has a distributed system with neurons located in its arms which appears to give each arm a high-level of autonomy. In addition to tactile sensory information from its suckers, each arm receives visual information from its skin which is sensitive to light. The extent to which information and control is shared between the neurons in the brain and the network of neurons in its body is unknown. It is difficult for us to imagine our fingers as being able to respond independently to visual as well as tactile stimuli, even more so to think of them as independent problem-solvers. Peter Godfrey-Smith suggests that cephalopods are the closest that we are likely to come to meeting intelligent aliens – their thought processes and capabilities appear so different to ours that our scientific studies and experiments are unlikely to fully reveal their intelligence or level of consciousness. A first step would be to stop eating them!
Peter Godfrey-Smith, Other Minds: The Octopus and the Evolution of Intelligent Life, London: William Collins, 2018.