"[H]aving worked out the markers that identify both aspects of consciousness in the vertebrates, we apply these same criteria to the invertebrates, and find that the arthropods (including insects and crabs) and cephalopods (like the octopus) meet many of the criteria for exteroceptive and affective consciousness. This would mean that consciousness evolved simultaneously but independently in the first arthropods and first vertebrates over half a billion years ago."