Did minimal consciousness drive the Cambrian explosion?

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Eva Jablonka is “one of the world’s foremost experts in epigenetic inheritance and evolution”, but she has also long been interested in studies of consciousness. She was author, with Marion J. Lamb, of Evolution in four dimensions: genetic, epigenetic, behavioral and symbolic variation in the history of life (MIT Press 2006 / rev. 2014).

Eva jablonka

She and neurobiologist Simona Ginsburg, as well as illustrator Anna Zeligowski, offer a new approach to the origin of consciousness in an essay at IAI.TV – an essay with an interesting departure from many approaches to consciousness:

Inspired by the Hungarian chemist Tibor Gánti (1933-2009), who posed a chimioton – the minimal life form or protocell – as the origin of life, they first try to define minimal consciousness, list of many requirements.

A minimal life form must show the capacity to learn, but it must also be a “subject of experience”. After all, like Ginsberg et al. Point out that the MuZero algorithm can beat humans at any number of games, but it is “as aware as your washing machine.” They argue that “the evolution of learning has driven the evolution of consciousness, and the cognitive architecture of complex learning in living organisms constitutes core consciousness.”

Where their approach differs a lot is that they do not try to identify a mechanism of consciousness. In fact, they write,

The next step we took was to find an evolutionary transition marker that requires all of the characteristics we have listed to be in place. We looked at genes, proteins, anatomical regions of the brain, and neurophysiological processes, but none of the many possibilities we looked at involved all of the characteristics of consciousness.

Simona Ginsberg, Eva Jablonka and Anna Zeligowski, “The origin of consciousness: identifying the evolutionary markers of the explosion of consciousness” at IAI.TV (August 20, 2021)

Rather, they are looking for transition markers between one stage of consciousness and the next, in terms of actual behavior. They opted for the concept of unlimited associative learning (UAL). It’s an interesting shift in emphasis if we remember a 1998 scientific bet between two big names in consciousness studies:

TWENTY years ago this week [1998], two young men were sitting in a smoky bar in Bremen, northern Germany. Neuroscientist Christof Koch and philosopher David Chalmers had spent the day giving a lecture on consciousness, and they had even more to say. After a few drinks, Koch suggested a bet. He bet on a case of fine wine that over the next 25 years someone would discover a specific signature of consciousness in the brain. Chalmers said that would not happen and bet against it.

By Snaprud, “Consciousness: How do we solve a mystery greater than our mind” at New scientist (June 20, 2018)

Well, the bet has only two years to run now and, barring some sudden and dramatic discovery, it seems that consciousness is not a “specific signature” at all.

The next book from the main authors, 2022

One reason to doubt such a signature is provided by the findings of Ginsberg’s team: if a physical “signature” explained consciousness, we might expect to find that consciousness follows rules which forms of life. over evolutionary time have demonstrated at least minimal consciousness, they found,

Our survey of the vast (but very patchy) learning literature of the past 100 years found no evidence of LAU. [unlimited associative learning] in most groups of animals, including jellyfish, tapeworms and slugs. It has, so far, been found in only three groups: most vertebrates (fish, amphibians, reptiles, birds and mammals), some of the arthropods (eg, crabs, bees, crickets, cockroaches) and some molluscs (the cephalopod – squid, cuttlefish and octopus) .. We have found that although the brains of these animals are anatomically very different, they have similar functional units that generate models of the world, body and forward-looking actions, a memory system that can store composite representations, and an integrative and flexible system that evaluates and updates them. This cognitive architecture gives us a clue about the function of consciousness: it allows the organism to make contextual decisions based on its subjectively experienced perceptions and motivations.

Simona Ginsberg, Eva Jablonka and Anna Zeligowski, “The origin of consciousness: identifying the evolutionary markers of the explosion of consciousness” at IAI.TV (August 20, 2021)

If the brains of life forms are anatomically very different, it makes more sense to follow consciousness through evidence of behavior, as researchers do, than through long sought-after evidence of anatomy. But it does involve decoupling consciousness from a specific physical structure. This is a different direction from the 1998 bet.

Ginsberg’s team argues for the Cambrian explosion as the first evidence of minimal consciousness:

Fossil records have told us that in arthropods and vertebrates, brain structures that could support ALU and consciousness first appeared in the Cambrian Era, a geologically short period beginning 542 million ago. years (MYA) and ending 485 MYA. This era is aptly called the Cambrian Explosion, as it was during this period that almost all of the currently extant animal phyla appeared and diversified. Cephalopod molluscs [squid, cuttlefish, and octopus] appeared in the fossil record 250 million years later, therefore UAL and consciousness seem to have appeared more than once and the early origins of UAL are indeed very old.

Simona Ginsberg, Eva Jablonka and Anna Zeligowski, “The origin of consciousness: identifying the evolutionary markers of the explosion of consciousness” at IAI.TV (August 20, 2021)

In short, proper brain structures are needed to support minimal consciousness, but they don’t need to be specific. On the contrary, intelligent cephalopods seem to be an example of convergent evolution – a common target rather than a common ancestry. For example, cephalopods have a much closer common ancestor with the nautilus than with the bird. Yet birds definitely show consciousness, while the nautilus is not known for any consciousness (or intelligence).

Ginsberg et al. argue that minimal consciousness was one of the factors that drove the Cambrian explosion:

Unlimited associative learning was an adaptive strategy that dramatically expanded the ability of animals to learn to harness new environmental resources in their own lifetimes. Was this therefore one of the driving forces behind the Cambrian explosion? We believe it was.

Simona Ginsberg, Eva Jablonka and Anna Zeligowski, “The origin of consciousness: identifying the evolutionary markers of the explosion of consciousness” at IAI.TV (August 20, 2021)

A difficulty Ginsberg et al. The face (which anyone doing this type of research would face) is that we cannot study Cambrian life forms as if they were alive. We can infer the behavior of body parts, but there is a lot we might not know from fossils alone (did they participate in mating rituals or conflict, for example?). That said, the team’s behavioral approach to minimal consciousness is likely to prove more useful, given what we already know, than looking for a consciousness module in the brain. However, we need to view consciousness as a less material characteristic, even in animals, than many theorists would like.


You can also read: Science reporter: No hype! Consciousness is a difficult problem. Michael Hanlon reflected on the many futile efforts to “resolve” consciousness.


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