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!
Many people are increasingly using their mobile phones as mental prostheses to extend the capacity of their brains [see ‘Science fiction becomes reality‘ on October 12th, 2016]. This does not just include tracking their appointments in a calender app or using a search engine to track down a piece of information that they have temporarily forgotten; but also recording their activities and preferences via social media apps. Many of us are happy to share our thoughts with those close to us but we take it for granted that we are in complete control of what is shared and with whom. So, unexpected or unauthorised sharing of our personal information via these mental prostheses can cause shock and embarrassment. Now, spare a thought for the giant cuttlefish whose neurons are directly connected to about ten million chromatophores in its skin. Each chromatophore is sack of pigment that can be shrunk or expanded to show its particular colour. In giant cuttlefish the chromatophores are red, yellow and black/brown. Beneath the chromatophores is a layer of iridophores, which manipulate the wavelengths of light using layers of plates to produce blues and greens and below these cells are leucophores that reflect light outwards through the iridophores and chromatophores. In effect, the cuttlefish is wearing an Ultra-High Definition TV screen with about 10 million pixels directly connected to its brain. Even when resting calmly, a cuttlefish’s skin can be pulsing with complex patterns of colour; perhaps this is similar to the way our minds can be teeming with activity even when we are sitting quietly apparently doing nothing. Imagine what it would be like if all of those thoughts were displayed on a giant television screen. It would give a whole new meaning to the phrase ‘to wear your heart on your sleeve’.