Humans often tend to believe that they are the only species to possess certain abilities, especially cognitive or mental abilities. From evidence coming from experimental studies with other primates, it has been shown that this exceptionalism does not hold. Higher cognitive functions, such as social cognition, theory of mind and emotion processing are also present in animalsnon-humans.
Besides primates, another model animal in cognition studies is the crow. Research recently published in Science found that crows are capable of abstractions about their own actions, and can even ponder the contents of their own minds, which is definitely a manifestation of intelligence and analytical thinking - something long credited as uniquely human.
Human subjective experiences are accessed consciously from the activation of the cerebral cortex. Consciousness is a phenomenon much explored by philosophy of mind, psychology and neuroscience. There is phenomenal consciousness, which is the experience itself, and access consciousness, which is the processing of things we experience during the experience. In neurobiology, consciousnesssensory is equivalent to access consciousness, since experiences depend on sensory stimuli. It is not known whether such a level of consciousness can also arise from differently organized brains, for example in a cerebral cortex divided into layers, such as the bird brain.
The authors of the aforementioned study recorded single neuron responses in the pallial encephalon of crows performing a visual detection task correlated with the birds' perception of the presence or absence of stimuli, and argued that this would be an empirical marker of sensory awareness in these animals. The experiment clearly demonstrated that crows can maintain a representationThis is a type of visual task that has been used in primates to distinguish what happens in the brain when an animal consciously detects a stimulus and when it does not.
Two crows were trained to perform the behavioral task, while hundreds of neurons in a specific part of the bird's brain were recorded. The birds would receive a stimulus or not receive it for a brief period - so brief that sometimes they could detect and sometimes they could not. The ability to detect probably depended on the current internal state of the crow's brain. After abrief period, the crows were exposed to a rule, which told them how they should act in response to the presence or absence of a stimulus.
THE EXPERIMENT: Ravens received a brief visual stimulus of varying intensity on 50% of trials (stimulus trials), while no stimulus appeared on the other half of trials (no stimulus). After a delay period, a rule informed the raven how to respond if it had seen either the stimulus. The raven's neuronal activity responded according to the rule.
The experiment setup allowed for the separation of stimulus input (input) and the animal's perception. In particular, crows could be wrong in two ways: they could fail to see something when a stimulus was actually presented, or they could think they saw something when no stimulus was presented, leading to a distinction between direct visual stimulation and subjective experience.authors took these data as evidence of "access awareness", processing of things we experience during experience, meaning that some internal neural state, a specific cognitive pattern representing something in the external world encoded dedicated neural networks, can be temporally maintained even in the absence of the stimulus and that this information can be made available,accessed or transmitted to the rest of the nervous system.
The Brazilian neuroscientist Suzana Herculano points out that the pallium is a portion that can represent up to 75% of the brain volume of birds, and is an area responsible for intelligence in these animals. Since their neurons are smaller, the pallium of crows and other birds comprises many more neuronal units for processing information than the cortexes of mammals of equivalent size.
In addition, crows, like primates, have developed a high-capacity memory that reflects the result of the convergent evolution of higher cognitive abilities in both species. Cognition being a type of psychological adaptation, some selective pressures have been postulated as causes of the evolution of cognition, namely, pressures favoring foraging efficiencyresulted in brain expansion and formation of sophisticated cognitive modules for spatial and temporal memory, working memory, and sensory awareness.
According to evolutionary biology, these animals have developed specializations to remember, encode, and predict the location of resources that are irregularly distributed in time and space, essential for survival and reproduction. When a food supply is abundantly available, many animals store an amount for consumption in later periods of scarcity ofHowever, to retrieve stocks effectively, these species need to process information related to the location, type and perishability of stored food items and the social context of storage. Note that we are talking literally about stock control and resource management skills.
Some corvids, such as Clark's Nutcracker ( Nucifraga columbiana ) can hide up to 33,000 pine seeds in 5,000 hiding places that can be about 25km away from the collection site, recovering most of them up to six months later. Such behaviors suggest that these birds have a very advanced long-term spatial memory. On the other hand, other corvids, such as the common jay ( Garrulus glandarius ), store fewer but a wider variety of food items that differ in their perishability rates. Consequently, they not only remember where they stored, but also what they stored and when, so that perishable food can be retrieved when it is still edible.
Since we are also talking about mind, cognition, and comparative evolutionary psychology, it is worth mentioning "place cells," neurons located in the hippocampus (in humans, monkeys, bats, and other mammals). What do place cells do? They encode space. When an animal enters a given location, which is known as a local field, place cells actas a cognitive representation of specific location in space, called a cognitive map, as the animal travels through the environment in lines, random or otherwise, as shown in the last image. The firing patterns of place cells are often determined by stimuli in the environment, including visual landmarks or olfactory stimuli, a very similar neural processingwith that of the corvids, which allows them to locate their food stocks.
Ravens are leading much of the revolution in scientific and philosophical opinion about intelligence in non-human animals and what biological evolution can tell us about consciousness and individuality, but none of this seems to be news to ancient peoples.
Huginn and Muninn sitting on Odin's shoulders in the illustration from an 18th century Icelandic manuscript.
Crows appear in different mythologies and folklores, in literature and in religions. In some cases, these black-feathered birds are considered an omen of bad news, but in others, they may represent a divine message. Crows sometimes serve as a method of divination and prophecy. In Native American folklore, the intelligence of crows is often portrayed as theirmost important characteristic. An ancient Greco-Roman adage, told by Erasmus, says that "the swans sing while the crows are silent," which means that educated or wise people will speak after the fools are silent.
The Roman poet Ovid saw the raven as a harbinger of rain. In the biblical account of the Old Testament it was the ravens that fed Elijah in the cave. Crows are the messengers in Hinduism, as carriers of information that give people omens regarding their situations. In the biblical legend of Noah's ark and the Epic of Gilgamesh, ravens are released to probe the world after the flood. In theChinese mythology, the world originally had 10 suns spiritually embodied as 10 crows.
In Irish mythology, ravens are associated with Morrigan, the goddess of war and death, and what of Edgar Allan Poe's talking raven? Or of Huginn and Muninn, Odin's pair of messenger ravens that fly over all of Midgard? Incredibly the meaning of the names Huginn and Muninn in the Old Norse language is "thought" and "memory," respectively, two abilities that the sciencesbehavioral evolutionaries are exploring in these amazing birds.
This article appeared first on Ethology & Sociobiology.