What insects can tell us about the origins of consciousness

Abstract

How, why, and when consciousness evolved remain hotly debated topics. Addressing these issues requires considering the distribution of consciousness across the animal phylogenetic tree. Here we propose that at least one invertebrate clade, the insects, has a capacity for the most basic aspect of consciousness: subjective experience. In vertebrates the capacity for subjective experience is supported by integrated structures in the midbrain that create a neural simulation of the state of the mobile animal in space. This integrated and egocentric representation of the world from the animal's perspective is sufficient for subjective experience. Structures in the insect brain perform analogous functions. Therefore, we argue the insect brain also supports a capacity for subjective experience. In both vertebrates and insects this form of behavioral control system evolved as an efficient solution to basic problems of sensory reafference and true navigation. The brain structures that support subjective experience in vertebrates and insects are very different from each other, but in both cases they are basal to each clade. Hence we propose the origins of subjective experience can be traced to the Cambrian. subjective experience | primary consciousness | vertebrate midbrain | central complex

Animal Consciousness

“…One remaining dimension is to estimate and test the validity of this metric theoretical paradigm in birds and fishes, and even invertebrates. For instance, the recent proposal of consciousness in insects (Barron and Klein, 2016) requires a challenging evaluation of Phi in this invertebrate class.…”

“…The integrated picture is enriched because it gives a sense or content to the information; for example, it is not possible to experience visual shapes independently of their colour, or perceive the left half of the visual field independently to the right half (Tononi and Laureys, 2009; see Chapter 2). The integrated relevant information can be made accessible for detecting anomalies and errors, decision making, developing strategies, further planning, inferring the internal or motivation state of other animals and, at least in humans, setting long-term goals and strategies and rational thought (Barron and Klein, 2016;Koch and Tsuchiya, 2007;.…”

“…Proprioceptors -sensors that provide information about joint angle, muscle length, and muscle tension-, nociceptors -sensors involved in pain perception-, and various chemical sensors in the gut provide information on the posture and spatial position of the body, of possible tissue lesions and of the digestive status. These and other sources of information related for example to memory, need to be compiled by the brain into an integrated image for further use (Barron and Klein, 2016;.…”

Fish and microchips: on fish pain and multiple realization

“…Although few would doubt that most mammals are conscious, debates revolve around the possibility of fish, cephalopods, crustaceans or insects being conscious, and more specifically, feeling pain (Allen (2004); Edelman et al (2005); Edelman and Seth (2009);Elwood (2012); Godfrey-Smith (2017); Griffin (1976); Tye (2017)). The most central debate features proponents of consciousness in animals such as fish (Braithwaite (2010); Huntingford et al (2006); Jones (2013); Sneddon (2011)) and insects (Barron and Klein (2016)) versus opponents to the existence of consciousness in those animals (Derbyshire (2016); Rose (2007); Rose et al (2014); Key (2015Key ( , 2016; Key et al (2016)). …”

Does a painless death harm an invertebrate?

“…While some researchers have argued invertebrates are conscious (Elwood and Apel 2009;Merker 2007;Tye 2000;Crook, Hanlon and Walter 2013;Mather 2008;Klein and Barron 2016), have beliefs and desires (Tye 2000;Carruthers 2005), and that the humane treatment principle ought to be extended to invertebrates (Cooper 2011;Crook 2013; see also Fischer 2016), little attention has been paid to the ethics of painless killing. Does a painless death harm an invertebrate?…”