Whether it is a mollusk or an insect, it looks to us like a collection of undifferentiated individuals. In fact, they also have emotions, can also perceive pain, and even have their own inner world!
invertebrate:
Another branch of the Tree of Life
Animals are often divided into two broad categories: vertebrates (mammals, birds, fish, amphibians and reptiles) and invertebrates (crustaceans, insects, molluscs, etc.), with the latter group including 95% of animal species. The last common ancestor of these two major groups of animals can be traced back 600 million years, and since then, the two species have diverged separately, eventually forming the current situation. Invertebrates do not have endoskeletons, and the brains that are highly concentrated in vertebrates, especially humans (the orange part of the photo below), are smaller and more dispersed in invertebrates.
We stomped on them, flattened them, threw them into boiling water to burn, drowned... For shrimp and crabs, shellfish, insects, spiders and so on, humans do not have the slightest compassion. These vertebrate animals are of a large number of species, accounting for more than 95% of the earth's animal species, and are an ordinary and huge "untouchable" class in the animal dynasty. Perhaps because their evolutionary paths are too far apart from humans, we only see them as oddly shaped, repulsive, and difficult to identify with. Moreover, they are not the same as dogs, if we accidentally step on the dog's paws, it will jump up and protest loudly, but these guys can't talk about such a performance, at most some superficial reflections, at least on the surface... As Florence Burgat, a philosopher at the French Academy of Agricultural Sciences (INRA), points out: "Official statistics on laboratory animals do not include invertebrates, they are seen as a bunch of inanimate objects, like used medical rubber gloves and syringes." ”
It's just that in recent years, studies on invertebrates have yielded refreshing results, proving that some of these "inferior animals" have good cognitive and perceptual abilities, sometimes even comparable to mammals! On July 7, 2012, world-class neuroscientists gathered at cambridge university to draft an official declaration that most invertebrates, especially octopuses, are conscious! This statement is a bit confusing to anyone who has ever picked up hermit crabs by the sea, but it actually reflects the huge question marks that scientists face: What are the brains of invertebrates? Do they also have emotions? Could it be that these seemingly inferior animals also have a colorful inner world?
These questions have existed since the time of Aristotle, and not only from a philosophical or poetic point of view. In fact, improving the environment for raising and slaughtering livestock has become a specialized field of scientific research. Fanatical animal protection organizations aside, the idea of "animal welfare" has infiltrated peer-reviewed scientific journals and laboratories at universities around the world. After the perceptual abilities of cattle, pigs, chickens, and ducks have been recognized, it is now the turn of the objects of ethical reflection to invertebrates, as people raise them equally intensively, eat them, or dissect them in the laboratory— and without anesthesia.
That's what the law says
Apart from some endangered species, invertebrates have no identity to speak of. However, from 1 January 2013, EU Decree No. 2010/63 on animal testing clearly stipulates that subjects of cephalopods (octopus, squid, etc.) should be treated with caution because they perceive pain and panic.
Brain function is no different
It must be admitted that, at first glance, the brain talent of invertebrates is limited. The mammalian brain is like a large, well-developed central processing unit, covered with a grooved neocortex; in contrast, the little bit of poor brain tissue in an invertebrate is just a set of vaguely shaped nodules. It's two different things entirely.
And it is this significant difference in structure that confuses the public. Ralph Greenspan, a neuroscientist and fruit fly expert at the University of California, explains: "Despite anatomical differences, the brains of invertebrates are no different from those of vertebrates from vertebrates from a functional point of view. Martin Giurfa, a bee expert at the Animal Cognition Research Center at the University of Toulouse III in France, analyzed: "Even though these two branches of animals have diverged beyond recognition hundreds of millions of years ago, their brains have since experienced the same survival pressures: finding nests and food, breeding offspring, and escaping danger..." He also found that "there are similarities between the olfactory bulbs of vertebrates and the antennae of insects." In addition, on a functional level, similar neurons exist in the bodies of the two types of organisms, such as antagonistic neurons that recognize color. "The same is true of crustaceans, even if there is no retina, it does not prevent them from seeing things, even very clearly!" It follows from this that even without neocortex, in theory they can have a variety of emotions.
However, does the size of the brain really have no effect on function? Because the numbers are there: the human brain has about 86 billion neurons, the octopus has about 200 million, while the bees have only 1 million, the spiders have 600,000, the fruit flies have 200,000 ... In addition to basic physiological reactions, can such a meager family withstand other external stimuli?
Bees are able to use abstract concepts that we previously thought were patents for humans and other primates
Martin Kirface
Expert, Centre for Animal Cognition Studies, University III of Toulouse
Complex systems
The formation of the inner world requires several prerequisites: to have feelings, to be able to synthesize all kinds of information from the outside world and coexist as memories, to be aware of one's own history — it doesn't matter if it is simple — and to learn from it. Can the invertebrate brain do all this? On this question, Ian Meinertzhagen of the Laboratory of Invertebrate Neurobiology at Dalhousie University in Canada argues that "the degree of diversity of related neurons and the degree of connectivity of them – in other words, the complexity of the nervous system – is more critical than the number of neurons." At this point, the fruit fly's visual system is at least as complex as the vertebrate retina. ”
Bruno van Swinderen, a cognitive scientist at the Queensland Brain Institute in Australia, is more radical: "What many brains have in common is nothing more than the production of complex neural activity that has nothing to do with external stimuli, signals that can rise to mental activity and do not have to be produced by mammalian brains." The conditions required for its generation, a sufficient number of neurons, a certain degree of connection, stimulation and inhibition circuits, synaptic plasticity, etc., are even available in simple animals such as fruit flies. From this point of view, it is not a big deal that invertebrates have feelings.
For ethical reasons, most current research involving invertebrate emotions focuses on the most primitive level: pain, an abnormal discomfort that comes from certain body tissues and can be perceived by the brain. The study is difficult because merely observing the lobster's violent reaction in boiling water does not tell the story. "All animals, even bacteria, with the exception of sponges and tapeworms, have this reaction of retracting and fleeing." In fact, the necessary condition for the survival of species is to seek advantages and avoid harms. George Sharpje explained.
This instinctive response does not necessarily represent pain perceived through the central nervous system. Similarly, "capturing neurons activated by harmful stimuli does not convey to us the true feelings of animals," notes Robert Elwood, an expert in animal behavior at Queen's University Belfast in Northern Ireland. On the contrary, long-term observation of the behavior of these neglected animals can lead to more accurate inferences... The premise is not to fall into the misconception of anthropomorphism, such as over-interpreting the spasms of pests after being sprayed with insecticides.
Depressed bees
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In preparation training for the Kaniola bee, the researchers linked odor A to a reward and odor B to a punishment. The trained bees were divided into two groups, one of which was placed in a centrifuge and turned violently for 1 minute, causing predators to attack their hives. For the next 5 minutes, the researchers showed all the bees 5 different scents, scent A, scent B, and three scents in between. Experimental results: Bees that have been "tossed" are more likely to interpret ambiguous smells as "punishment" smells. Their judgments, that is, their feelings about the world, are imprinted with "pessimism" from a cognitive point of view, just like human depression. This suggests that bees may also develop anxiety.
Something other than basic reflection
For 5 years, Robert Elwood has been working to reveal the pain response of crustaceans through rigorous experiments. In 2007, he applied a harsh solution to one side of the tentacles of 144 shrimp and found that they were then wiped desperately. "This continuous and directional behavior is beyond the scope of simple reflection." He analyzed. Two years later, he selected a group of hermit crabs and provided them with shells of varying masses, while administering electric shocks of varying intensities. "The compromises they take suggest that they were judged by the brain, which seems to mean they have pain." Similar experiments on vertebrates have come to this conclusion. He wrote. Recently, the same experiment has been successful in ordinary coastal crabs.
Unfortunately, pain is an inner experience that cannot be measured directly, and it is "almost impossible to obtain conclusive evidence," admits Robert Elwood. If this were the case, then no one would be able to comprehend what the discomfort felt by the hermit crab and our very different nervous systems was, let alone clearly distinguish between physical pain and mental pain. Still, like some other researchers, Florence Bogay reasoned that "these animals lacked sufficient cognitive abilities to drain pain, such as not being aware of its transient nature, and were therefore completely engulfed by the pain." Their suffering is real."
Invertebrates are emotionally rich? Narratives of their happy, fearful, or angry behaviors are often just tidbits and are very carefully worded. For example, Jennifer Mather, a psychologist at the University of Lethbridge in Canada, points out that in some special cases, "octopus discoloration may be a sign, a sign that reflects its inner feelings, although it cannot be verified." Jonathan Pruitt of the University of Pittsburgh in the United States, while studying ctenopod spiders, noticed that they "have certain social behaviors —such as simulating tailcrossing, approximating a game... It's just hard to determine if they're getting pleasure from it."
30 years ago, in sea hares, a common animal studied in neurobiology, Edgar Walters of Texas State University discovered that "a behavior that is functionally equivalent to a human conditional fear response." The experiment is very famous. But the American scientist immediately cautioned: "This does not mean that sea hares are as aware of fear as humans." "The stakes couldn't be clearer: In the 18th century, scientists used the dance of bees as a celebration of their discovery of wild flowers, and now we know it's to tell our companions where the food source is."
Clever octopus
After 9 years of tracking in Indonesian waters, researchers found the interesting behavior of 20 side slugs (Amphioctopus marginatus): They would use sunken coconut shells to create shelters to protect their fragile bodies (pictured). It's not just a simple matter of seeking asylum, as these octopuses carry coconut shells over long distances for later use – which is a tool for them. It's a very advanced cognitive ability, almost close to intelligence, and people thought it was the preserve of a few mammals and birds.
Probe their mental state
Given the inability to directly measure all aspects of invertebrate emotions, some research teams are now studying these animals through psychological testing. The purpose of conducting this "cognitive bias" test is first and foremost to probe whether their mentality is positive and negative. In 2011, an experiment led by Melissa Bateson, an animal behaviorist at Newcastle University in the United Kingdom, showed that a bee that was stunned showed "pessimistic cognition". But this result was criticized by the academic community after it was published. Bruno V. Vans verderen argues that it is inappropriate to talk about "emotions" here: "In the same experimental procedure, in the face of another stimulus, bees can also become extremely aggressive instantaneously, and we cannot tell whether this is due to anger or pure mechanical reaction." But Melissa Batson argues: "At least for now, the experimental procedure has been considered the standard procedure for detecting negative emotions in animals." We have to be logical, we can't say that only dogs or rats that exhibit this cognitive bias are anxious, and bees are not. Either the bees are as emotional as the vertebrates, or the experiment is meaningless. These few words are a good reflection of the resistance encountered in invertebrate research.
One thing is certain, however, that it is increasingly difficult to deny that these small animals have a certain intelligence. Just look at the octopus's amazing series of behaviors. "Octopuses also have different personalities and are highly capable of learning." Jennifer Mather introduced. Experiments have shown that their cognitive abilities surpass those of fish and reptiles, and are on par with birds and even some mammals.
But octopuses aren't the only invertebrates that have attracted the attention of scientists, but also bees. Martin Kielfa has just demonstrated that "they can use abstract concepts such as 'above' or 'different'; it's a high-level treatment that we previously thought was the preserve of humans and other primates." Robert Jackson, a biologist at the University of Canterbury in New Zealand, found some clues through the hole spider: "Our experiments have proved that they can maintain an impression of prey out of view and design offensive routes accordingly." This is related to what psychology calls 'object persistence', an ability that depends on the 'inner world'. "For reference, human babies must be 18 to 24 months old to develop this ability, in other words, it is not simple!
These results, while scattered, are at least thought-provoking. Bruno Vans verderen argues that, in general, "most animals have some ability to remember, and now we have found that even the simplest ones have selective attention." Both of these mechanisms intervene in emotions, and when they interact, that is, when attention is directed to individual memory, it is possible to form consciousness." Of course, no one thinks an octopus would have any thoughts. Just feel, maybe in some way, that they are able to form a subjective impression of the world, or experience an emotion and be soberly aware of it, such as "My tentacles hurt!" "What's not to like? There is no rule today that consciousness can only originate from certain parts, such as the cerebral cortex and neocortex.
In fact, David Edelman, a neurophysiologist at Bennington College in the United States, believes that "the key is to understand how complex the nervous system is enough to produce consciousness." This is an attractive question, but no one can answer it at the moment. Some are just all kinds of speculation.
A spider with a rich heart
624 hole spiders participated in the experiment. Experimental setup: Two "runways" with forks made of aluminum tubes, path A leads to a prey, and path B leads to an empty box. Everything is in the path design: the hole spider, which can choose its own path, leaves the starting point and can no longer see its prey. The researchers put the hole spiders, which had been hungry for 10 days, on the starting point, and after observing their surroundings, they ran towards their prey. The experimental results show that in general, although the path is winding and the prey is not visible, most of the hole spiders will choose the right path. This shows that they preserve mental imagery of prey and complex paths, reach a higher stage of psychological development, and have "object persistence". Human babies don't have this ability until they are 18 to 24 months old.
The consciousness of the bees
"In my opinion, it is difficult to explain the amazing performance of the bee's small brain and its number of neurons, which are less than one-hundred-thousandth of a human brain." David Edelman points out that "perhaps there are other ways to organize than the 'rigid' connections of neurons." "Octopus is another promising object, and studies of their possible consciousness have appeared many times in authoritative scientific journals." There was once a study, of course, which was later controversial, revealing that one octopus would learn from another, which may be a manifestation of a form of consciousness. David Edelman added.
Bees, octopuses, and possibly spiders. What about fruit flies? Bruno V. Phams verderen expressed difficulty in identifying because "to be aware of one's emotions, one needs to have a long-term memory of them." And flies don't have enough memory and don't have enough time. Unless that's more than enough for fruit flies... Then I can't say for sure." Sid Kouider, head of the Brain and Consciousness Research Group at École Normale Supérieure de Paris, points out that at our current level of research, "it is difficult to argue that a biological being, including humans, exists without oral testimony." "Doing an EEG on an invertebrate may not be able to see anything." Are the EEG waveforms of some of the hallmarks of conscious activity the same for different species? Not necessarily. "Because we can't separate an individual's consciousness from its nervous system and body." Don't forget, even if the bee is conscious, it is the bee consciousness..."
"The Consciousness of the Bee" transforms our view of bees and, on a broader level, reverses our view of the mysterious inner world of invertebrates, a world that we have paid little attention to before. This is not to say that we should repent for most of the day now when we shoot a fly to death, as the Jains did in India – for whom it is a sin to kill any kind of creature. There is no need to overcorrect. It just makes us realize that from now on, the most basic respect should be shown to these "inferior citizens", who are also independent individuals, even a small spider hanging from the beams, even a hermit crab looking for empty shells.
Sensitive crabs
The experimental method is simple: an ordinary coastal crab, the fifth pair of feet connected to the wire, placed in the center of a large dry box, the box is equipped with shielding belts on both sides, simulating the crab to hide from predators at low tide. If it chooses concealment A, it will receive a short electric shock of 10 volts after 5 seconds, usually forcing it to leave the concealment. The second choice, it will often still choose hidden place A, so it is subjected to a second electric shock. But by the third time, most of the 41 coastal crabs used in the experiment began to learn their lessons, abandoning first choice A and switching to hidden place B without electric shocks, in order to avoid unpleasant feelings again. This process of reasoning reflects the crustacean's ability to feel pain.