Only mammals and birds are sentient, according to Nick Humphrey

Only mammals and birds are sentient, according to neuroscientist Nick Humphrey’s theory of consciousness, recently explained in “Sentience: The invention of consciousness”.

In 2023, Nick Humphrey published his book Sentience: The invention of consciousness (S:TIOC). In this book he proposed a theory of consciousness that implies, he says, that only mammals and birds have any kind of internal awareness.

His theory of consciousness has a lot in common with the picture of consciousness is described in recent books by two other authors, neuroscientist Antonio Damasio and consciousness researcher Anil Seth. All three agree on the importance of feelings, or proprioception, as the evolutionary and experiential base of sentience. Damasio and Seth, if I recall correctly, each put a lot of emphasis on homeostasis as a driving evolutionary force. All three agree sentience evolved as an extension of our senses–touch, sight, hearing, and so on. But S:TIOC is a bolder book which not only describes what we know about the evolutionary base of consciousness but proposes a plausible theory coming as close as can be to describing what it is short of actually solving Chalmers’ Hard Problem.

Read more:
https://forum.effectivealtruism.org/posts/AvubGwD2xkCD4tGtd/only-mammals-and-birds-are-sentient-according-to

 

Decapitation in Rats: Latency to Unconsciousness and the ‘Wave of Death’

The question whether decapitation is a humane method of euthanasia in awake animals is being debated. To gather arguments in this debate, obsolete rats were decapitated while recording the EEG, both of awake rats and of anesthetized rats. Following decapitation a fast and global loss of power of the EEG was observed; the power in the 13–100 Hz frequency band, expressing cognitive activity, decreased according to an exponential decay function to half the initial value within 4 seconds. Whereas the pre-decapitation EEG of the anesthetized animals showed a burst suppression pattern quite different from the awake animals, the power in the postdecapitation EEG did not differ between the two groups. This might indicate that either the power of the EEG does not correlate well with consciousness or that consciousness is briefly regained in the anesthetized group after decapitation. Remarkably, after 50 seconds (awake group) or 80 seconds (anesthetized group) following decapitation, a high amplitude slow wave was observed. The EEG before this wave had more power than the signal after the wave. This wave might be due to a simultaneous massive loss of membrane potentials of the neurons. Still functioning ion channels, which keep the membrane potential intact before the wave, might explain the observed power difference. Two conclusions were drawn from this experiment. It is likely that consciousness vanishes within seconds after decapitation, implying that decapitation is a quick and not an inhumane method of euthanasia. It seems that the massive wave which can be recorded approximately one minute after decapitation reflects the ultimate border between life and death. This observation might have implications in the discussions on the appropriate time for organ donation.

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A Brain Implant that Automatically Detects and Kills Pain?

It’s basically a tag-team of spy and sleeper agent. The “spy” listens to electrical chatter in a brain region that processes pain—along with dozens of other tasks—and decodes it in real time. Once it detects an electrical signal that suggests “pain found,” it sends the information to the “sleeper agent,” a computer chip implanted in the front part of the brain. The chip then automatically triggers a light beam to stimulate the region, activating neurons that can override pain signals.

Sources: https://singularityhub.com/2021/06/29/a-new-brain-implant-automatically-detects-and-kills-pain-in-real-time/

https://www.nature.com/articles/s41551-021-00736-7

https://www.eurekalert.org/news-releases/789517

 

 

A Cephalopod Has Passed a Cognitive Test Designed For Human Children

》…cuttlefish also passed a version of the marshmallow test. Scientists showed that common cuttlefish (Sepia officinalis) can refrain from eating a meal of crab meat in the morning once they have learnt dinner will be something they like much better – shrimp.

Source:

https://www.sciencealert.com/cuttlefish-can-pass-a-cognitive-test-designed-for-children

An empirical investigation of hedonistic accounts of animal welfare

“Many scientists studying animal welfare appear to hold a hedonistic concept of welfare -whereby welfare is ultimately reducible to an animal’s subjective experience. […] analysis showed welfare judgments depended on the objective features of the animal’s life more than they did on how the animal was feeling: a chimpanzee living a natural life with negative emotions was rated as having better welfare than a chimpanzee living an unnatural life with positive emotions. We also found that the supposedly more purely psychological concept of happiness was also influenced by normative judgments about the animal’s life. For chimpanzees with positive emotions, those living a more natural life were rated as happier than those living an unnatural life. Insofar as analyses of animal welfare are assumed to be reflective of folk intuitions, these findings raise questions about a strict hedonistic account of animal welfare. More generally, this research demonstrates the potential utility of using empirical methods to address conceptual problems in animal welfare and ethics.”

https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0193864

The Challenge of Determining Whether an A.I. Is Sentient, by Carissa Véliz

“…sentience may go unnoticed for years, as was the case with Martin Pistorious [1] … Because brain death can be misdiagnosed [2], and because we have little understanding of the necessary and sufficient causes for consciousness and therefore cannot be certain of when someone might be in pain, some experts have called for the use of anesthesia [3] for organ donation procedures.”

Read more:

https://slate.com/technology/2016/04/the-challenge-of-determining-whether-an-a-i-is-sentient.html

[1] https://www.ted.com/talks/martin_pistorius_how_my_mind_came_back_to_life_and_no_one_knew?language=en

[2] https://www.nytimes.com/2012/04/01/books/review/the-undead-by-dick-teresi.html?_r=0

[3] https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2044.2000.055002105.x

 

An organism able to learn and move with no brain, no mouth, no stomach, no eyes and 720 sexes

A Paris zoo is showcasing a mysterious creature dubbed the “blob,” a yellowish collection of unicellular organisms called a slime mold that looks like a fungus, but acts like an animal.

This newest exhibit of the Paris Zoological Park, which goes on public display on Saturday, has no mouth, no stomach, no eyes, yet can detect food and digest it.

The blob also has almost 720 sexes, can move without legs or wings and heals itself in two minutes if cut in half.

“The blob is a living being which belongs to one of nature’s mysteries,” said Bruno David, director of the Paris Museum of Natural History, of which the Zoological Park is part.

“It surprises us, because it has no brain but is able to learn (…) and if you merge two blobs, the one that has learned will transmit its knowledge to the other,” David said.

The blob was named after a 1958 science-fiction horror B-movie, starring a young Steve McQueen, in which an alien life form consumes everything in its path in a small Pennsylvania town.

“We know for sure it is not a plant but we don’t really [know] if it’s an animal or a fungus,” said David.

“It behaves very surprisingly for something that looks like a mushroom … it has the behaviour of an animal, it is able to learn.”

Source:

https://www.cbc.ca/news/technology/paris-zoo-blob-1.5325747

 

The search for invertebrate consciousness

There is no agreement on whether any invertebrates are conscious and no agreement on a methodology that could settle the issue. How can the debate move forward? I distinguish three broad types of approach: theory‐heavy, theory‐neutral and theory‐light. Theory‐heavy and theory‐neutral approaches face serious problems, motivating a middle path: the theory‐light approach. At the core of the theory‐light approach is a minimal commitment about the relation between phenomenal consciousness and cognition that is compatible with many specific theories of consciousness: the hypothesis that phenomenally conscious perception of a stimulus facilitates, relative to unconscious perception, a cluster of cognitive abilities in relation to that stimulus. This “facilitation hypothesis” can productively guide inquiry into invertebrate consciousness. What is needed? At this stage, not more theory, and not more undirected data gathering. What is needed is a systematic search for consciousness‐linked cognitive abilities, their relationships to each other, and their sensitivity to masking.

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