© Sandra Standbridge/Moment/Getty Images)Crow
New research into the minds of crows has revealed a jaw-dropping finding: the canny corvids aren't just clever - they also possess a form of consciousness,
able to be consciously aware of the world around them in the present. In other words, they have subjective experiences.This is called primary, or sensory, consciousness, and it had only previously been demonstrated in primates - which means we now may have to rethink our understanding of how consciousness arises, in addition to
reconsidering the avian brain.
"The results of our study opens up a new way of looking at the evolution of awareness and its neurobiological constraints," said animal physiologist
Andreas Nieder of the University of Tübingen.
Consciousness is difficult to pin down in animals that don't speak.
It's the ability to be aware of oneself and the world around you, to know what you know, and to think about that knowledge. It enhances problem-solving and decision-making - at both of which crows excel.
Primary consciousness is the most basic form of consciousness as we categorise it -
awareness of perceiving the world in the present (and the immediate past and future). Primarily, it's been associated with the primate cerebral cortex, a complex layered region of the mammalian brain.
But bird brains are structured quite differently from primate brains, and are smooth where mammalian brains are layered. So even though corvids - the bird family that includes crows and ravens - are
incredibly smart, with
cognitive abilities found in primates, questions remained over whether they could cross the line into conscious thought.
To find out, Nieder and his colleagues
designed an experiment to test whether birds could have subjective experiences, and tested it on two carrion crows (
Corvus corone).
First, the birds were trained to respond to visual stimuli. They were shown screens on which lights were displayed; if the crow saw the lights, they were to move their heads to show that yes, they had seen something. Most of the lights were clear and unambiguous, easy to see, and the crows reliably reported that they had seen them.
But some of the lights were a lot harder to spot - brief and faint. For these, the two crows sometimes reported seeing the signals, and sometimes did not.
This is where the subjective sensory experience enters the picture.For the experiment, each of the crows was shown roughly 20,000 signals, spread out across dozens of sessions. Meanwhile,
electrodes implanted in their brains recorded their neuronal activity.When the crows recorded a 'yes' response to seeing the visual stimuli, neuronal activity was recorded in the interval between seeing the light and delivering the answer. When the answer was 'no', that elevated neuronal activity was not seen. This connection was so reliable that it was possible to predict the crow's response based on the brain activity.
"Nerve cells that represent visual input without subjective components are expected to respond in the same way to a visual stimulus of constant intensity,"
Nieder said.
"Our results, however, conclusively show that
nerve cells at higher processing levels of the crow's brain are influenced by subjective experience, or more precisely produce subjective experiences."The results confirm that subjective experiences
are not exclusive to the primate brain - and that the complex layering of the mammalian brain is not a requirement for consciousness. In fact, a second new study finds that the smoothness of bird brains is not indicative at all of a lack of complexity.
Using 3D polarised light imaging and neural circuit tracing techniques, biopsychologist Martin Stacho of Ruhr-University Bochum in Germany and colleagues characterised the anatomy of pigeon and owl brains. They found that the
cerebral architecture in both birds is strikingly similar to the cerebral architecture of mammals.It's possible that similar cognitive abilities evolved independently in both birds and mammals, a phenomenon known as convergent evolution. But it's also possible that our brains are more closely related than their differences can suggest.
"Our findings suggest that it is likely that an ancient microcircuit that already existed in the last common stem amniote might have been evolutionarily conserved and partly modified in birds and mammals," Stacho and his team write.
Nieder agrees with this possibility.
"The last common ancestors of humans and crows lived 320 million years ago," he said. "It is possible that the consciousness of perception arose back then and has been passed down ever since. In any case, the capability of conscious experience can be realised in differently structured brains and independently of the cerebral cortex."
This means primary consciousness could be far more common across birds and mammals than we've realised.
If this proves true, the next and possibly even more fascinating question is: do these animals also possess secondary consciousness?
Are they aware that they are aware?
Reader Comments
regurgitation.
RC
[Link]
ANTARCTICA: A Cenos Base On Earth
and during the time of the Akkadian civilization on Earth about 4300 years ago.
[Link]
HANDS
UNIQUE DESCRIPTIONS OF TWO ET ALIEN CULTURES
See Figure 6 and the CONCLUSION section. This suggests that 'Birdman' home world may be Proxima b
Later that day, a crow landed on the deck railing where my husband and I were having a drink and my husband was eating crackers. The crow looked at us with that same quizzical, head-cocked look, and it crossed my mind that it was the same crow. I said to my husband: "Why don't you see if she wants a cracker?" He did, and she did...after he laid it on the deck railing and walked away. For the rest of that summer, she kept coming back to the same spot and we kept putting crackers on the railing for her.
We noticed that she was so dexterous she could flip crackers over with her beak so that they were neatly on top of one another and she could make off with 4 or 5 at a time. Because she would come back so many times each day, landing on her spot on the railing whenever I was out on the deck smoking, and take 4 or 5 at a time in the same manner, it occurred to me that she was either stashing them or feeding babies, or both. Later that summer, a pair of other crows showed up as well, and landed on the same spot on the deck railing, raucously calling for food. We fed them too.
Last summer a gang of crows showed up, led by a large specimen with an unusual crest on his head. We referred to him as the 'crow with no manners' because he would dive-bomb any crow (particularly 'our' crow) who went to take a cracker before him, even if he'd just eaten. He would also take his time eating crackers on the railing while the other crows waited hungrily in the trees for their turn, but didn't dare land while he was there. He disappeared some time last winter and we haven't seen him since.
Now there are 6 or 7 crows who wait in the trees while one or two land on the same part of the deck railing. The current group still includes 'our' crow and they don't seem anywhere near as concerned with maintaining a pecking order. Sometimes only one sits in the pine trees at the end of the garden and makes what I've come to think of as the "food alert" call whenever I go out on the deck. When I put out crackers there's a flurry of wings and crows come from all over the neighborhood to grab crackers together. Sometimes if I haven't been out for a while, there will be 3 or 4 crows dancing around on the railing in front of the kitchen window hoping to get my attention. It's pretty cute.
They never let us get too near them, but they don't fly off very far either when we come out with handfuls of crackers. They'll all come and take crackers even when I'm standing smoking on the other end of the deck. I often have to duck because they pay no attention to me when they fly towards the crackers. Some of them even stay and munch the crackers on the railing while I'm standing 6 feet from them.
I can't help thinking the first crow took the measure of my husband and I on that first day and decided to take a chance on what she saw and felt. Then I'd say she taught her children that our house is a food source. I couldn't say whether crows are aware that they are aware, but it definitely seems that some can make good decisions based on what appeared to be the flimsiest of evidence: a first impression.
RC
What made me wonder if you're speaking of different species is the crest, as I know that crows don't have them, and I doubt that N. American Ravens do, either. (I LOVE ravens. I would write a poem but . . . )
The way I remember critters hybridizing is that if you take a male donkey and a female horse, you get a strong, stubborn mule; do vice versa you get a relatively weak and stubborn hinny. Take two mules or hinnies? You'll never get anything. The definition of species is that they can give birth to fertile offspring.
There are a lot of songbirds (passerines) that can hybridize, but really they're usually the same species, such as the Eastern 'Baltimore' Oriole and the Western Bullock's Oriole which in the central USA look like a mix of the two and its been concluded that they're subspecies, or such. (Ain't a critter geneticist.)
R.C.