Abstract: On the face of it, cephalopods are unlikely candidates for consciousness, even at a primary level. They stem from slow, simple molluscan ancestors, but during evolution they have lost the protective shell. Likely in the competition with bony fishes, they have instead developed a centralized brain, acute vision, complex control of arm movement and a stunning skin display system. But unlike other non-human animals with well developed cognition, they are not social. What would the evolutionary pressure be, then, for these animals to develop consciousness? The answer may lie in the complexity of their near-shore marine environment. Mobile cephalopods must search this environment to find prey, and octopuses do so with a saltatory search technique. At the same time they are vulnerable to predators and have an array of defenses, from camouflage to false eye spots and ink release to flight, to avoid or react to them. Yet they are mobileâ€”octopuses move to a new home range every ten days or two weeksâ€”so they cannot store information and responses to form automatic loops. It may be this constant change and pressure to update that caused the cephalopods to develop a simple form of consciousness.
Mather, J. A. (2008). Cephalopod consciousness: Behavioral evidence. Consciousness and Cognition, 17, 37-48
Mather, J. A. (2010). What might consciousness in cephalopods be like? Journal of Cosmology (special issue on consciousness)http://journalofcosmology.com/Consciousness113.html
Philosophical background of attitudes toward and treatment of invertebrates http://research.tamucc.edu/compliance/iacuc/PDF/ILAR%20Journal.pdf#page=91
Behavioural indicators of pain in crustacean decapods http://www.scielosp.org/scielo.php?pid=S0021-25712009000400013&script=sci_arttext
Pain and suffering in invertebrates? http://www.vliz.be/imisdocs/publications/231732.pdf
New evidence of animal consciousness http://postcog.ucd.ie/files/fulltext.pdf
[See also David Edelman reference list]