The Case for Octopus Consciousness: Unity

Abstract

Birch et al. suggest that consciousness in any animal group must involve four aspects—perceptual richness, evaluative richness (affectivity), integration at one time (unity), and integration across time (temporality). This review will evaluate integration at one time in cephalopods, an area that offers many challenges. First, like most animals with a bilateral nervous system, cephalopods have laterality of brain function, and this challenges unity of function. Second, unlike most mammals, cephalopods have a heavy allocation of both neural and behavioural control to the periphery, especially in the case of octopuses. Third, like all animals, cephalopods gather information through several senses and there can be both unity within and competition between such information, challenging unity. Information gained across all these areas needs to be evaluated both in terms of the methodology used to gather information and the results of the investigation.

Where Is It Like to Be an Octopus?

“…Octopuses have appeared to be another challenger to the unity thesis, because of the extensive distribution of their nervous systems and cognitive routines and the considerable autonomy displayed by the highly elaborated peripheral nervous system. While there is accumulating evidence in favor of unity ( Mather, 2021 ), adjudicating whether octopuses experience multiple conscious fields or a single one requires independent investigation outside of present purposes.…”

“…They have lateralised vision, and are able to use a single eye for perceptual and learning tasks. Signals received via one eye are transmitted and processed in its ipsilateral optic lobe, which sends this information further upstream for “cross-brain transfer” ( Mather, 2021 , p. 408). Tasks learned while using one eye can later be performed with the other eye, although not as accurately or efficiently as with the original one.…”

“…Tasks learned while using one eye can later be performed with the other eye, although not as accurately or efficiently as with the original one. This is because “cross-brain transfer [of information from one eye] would normally be complete but storage or retrieval would not be as good in the contralateral as in the ipsilateral area of the brain” ( Mather, 2021 , p. 408).…”

“…Although there is reason to believe that intact octopuses experience a single conscious field ( Mather, 2021 ), the question remains as to where phenomenal experience in these animals is generated. In familiar models of consciousness, it is mostly the case that the CNS—particularly the brain—is the sole organ complex enough to be capable of generating a conscious field.…”

Cephalopod Behavior: From Neural Plasticity to Consciousness

“…We highlight the strengths, drawbacks, and lacunae when considering these animals as candidates for a distinct level or degree of consciousness. The topic has been covered previously in a series of papers (Mather, 2008 , 2021a , b ; Edelman and Seth, 2009 ; Birch et al, 2020 ; Feinberg and Mallatt, 2020 ). We will highlight the essential aspects of these works.…”