Sam Wang and Sandra Aamodt have an article in Dana Cerebrum (here), Play, Stress, and the Learning Brain.

They define play.

First, play resembles a serious behavior, such as hunting or escaping, but is done by a young animal or is exaggerated, awkward, or otherwise altered. Second, play has no immediate survival purpose. It appears to be done for its own sake and is voluntary and pleasurable. Third, play occurs when an animal is not under stress and does not have something more pressing to do.

If that is play then it occurs among many animals: mammals, birds, some other vertebrates and even some invertebrates (octopus, squid, honeybee). This wide spread points to a very long history and suggests it serves a vital purpose. Another indication of usefulness is that play is fun; enjoyment is a sign of survival traits. Play is rewarded with dopamine. It is tailored to the lifestyle of the animal. Depending on the typical behavior of the animal there are three types of play. Playing with objects is typical of species that hunt, scavenge or eat a variety of foods. Locomotor play is usual in active animals who run, swim, fly, climb trees. Social play (fighting, chasing, wrestling) uses pretending in animals who have important social encounters. It is the species with the bigger brains for their body size who most engage in social play.

So play has an adaptive purpose or purposes. What would they be?

play is practice that prepares animals for the real activity later—when it matters. … In mammals, play is necessary for forming normal social connections. Rats and cats raised in social isolation become incompetent in dealing with others of their kind and typically react with aggression. In our species, abnormal play as children often presages dysfunction in adults. A notable feature of psychopaths is that their childhoods lacked in play. … Play also transmits culture. … Risk taking in children’s play may be an important developmental process. It tests boundaries and establishes what is safe and what is dangerous. … play also helps children learn what they like and don’t like.

Interesting, playing is a low stress activity (either play lowers stress or stress interferes with play). This is important for learning during play.

Play activates other brain signaling systems as well, including the neurotransmitter

norepinephrine. … Norepinephrine is also involved in rousing us to attention and action, but by acting as a neurotransmitter. Norepinephrine facilitates learning mechanisms at synapses as well. In some neurons, norepinephrine improves brain plasticity, such that change becomes possible when this chemical is present in elevated amounts. The same is true for dopamine, which accounts for how reward leads to long-term changes to make us want more—neural plasticity mechanisms are strongly facilitated when reward occurs. … Though real-life stressors trigger the release of both epinephrine and cortisol, play does not increase cortisol. Cortisol is a stress hormone that helps us in genuinely dangerous situations by redirecting resources to the most urgent needs, such as repairing a wound or fighting an infection.

For humans, play continues into adulthood.

work in adult life is often most effective when it resembles play. Indeed, total immersion in an activity often indicates that the activity is intensely enjoyable; this is the concept of flow, or what athletes call being in the zone. Flow occurs during active experiences that require concentration but are also highly practiced, where the goals and boundaries are clear but leave room for creativity. This describes many adult hobbies, from skiing to music, as well as careers like surgery and computer programming. Such immersion can make solving a great challenge as easy as child’s play.

And not just humans play as adults. Dogs do and they have a special signal to commence play so that their actions are not misunderstood. It is a similar signal in many animals and young of different species have been seen playing together.

What has this to do with consciousness? It seems to me that play is like a type of consciousness – a way of experiencing the world that can be turned on and off. We are able to experience a low tension, enjoyable, somewhat pretend world in which we actively experiment, discover and learn.

Three ways to build a brain

Only mammals have a neocortex. But we know from behaviour that birds and reptiles think a lot like mammals. They must have structures and processes similarly to a neocortex.

ScienceDaily has a report (here) on research by Dugas-Ford and others in a PNAS paper, Cell-type homologies and the origins of the neocortex. The group looked for neurons similar to those in the neocortex in birds. This supports a 50 year old hypothesis.

Both the mammalian neocortex and a structure in the bird brain called the dorsal ventricular ridge (DVR) originate from an embryonic region called the telencephalon. But the two regions mature into very different shapes, with the neocortex made up of six distinct cortical layers while the DVR contains large clusters of neurons called nuclei. … in the 1960s, neuroscientist Harvey Karten studied the neural inputs and outputs of the DVR, finding that they were remarkably similar to the pathways traveling to and from the neocortex in mammals. As a result, he proposed that the DVR performs a similar function to the neocortex despite its dramatically different anatomy.

Dugas-Ford, Ragsdale and co-author Joanna Rowell decided to test Karten’s hypothesis by using recently discovered sets of molecular markers that can identify specific layers of mammalian cortex: the layer 4 “input” neurons or layer 5 “output” neurons. The researchers then looked for whether these marker genes were expressed in the DVR nuclei.

They found the level 4 and 5 markers in chicken and zebra finch. But instead for being in layers as in the neocortex, in the DVR the marked cells are in distinct nuclei. They looked at turtles as well and found the level 4 and 5 markers but this time in a single layer on the dorsal cortex. There may be advantages and disadvantages to the different structures using these neurons.

The complex language and tool-use of some bird species suggests that the nuclear organization of this pathway is also capable of supporting advanced functions — and even may offer advantages over the mammalian brain.

“If you wanted to have a special nuclear processing center in Broca’s area to carry out language processing, you can’t do that in a mammal,” Ragsdale said. “But in a bird they have these special nuclei that are involved in vocalization. It’s as if you have additional flexibility: You can have shorter circuits, longer circuits, you can have specialized processing centers.”

We can look forward to this putative homology being productive in studying the embryonic development of the brain and in understanding the mechanisms of neocortex activity.


How can self-awareness be measured?

I have often thought that there was a problem with the measurement of self-awareness in animals. For some time self-awareness has been identified with self-recognition and self-recognition with the mirror test.


So far the mirror recognition test has been passed by humans, bonobos, chimpanzees, orangutans, gorillas, dolphins, oras, elephants and magpies. It has sort of, maybe, been passed by some other birds and monkeys. We cannot believe that only those animals are self-aware. Where are the dogs, big cats and similar? Watch a pair of sheep dogs work sheep; watch a group of lions take their roles in an ambush; can that behavior happen without self-awareness? How do octopuses know when their camouflage is a perfect match for their environment? And why do Kenyan children fail the mirror test and American children pass it at the same age? The problem is that the mirror test needs more that self-recognition.


First the animal needs to understand the concept of reflection and that the mirror is giving a reflection and it is of themselves; second they have to behave in a way that shows that they know they have seen themselves (find and try to remove a mark on their bodies). It will not do if the animal has some other interpretation of the mirror’s image or some other reaction to it. What if they reject the image because it doesn’t smell right? What if the whole procedure frightens them? What if they refuse to look at the image? What if they do not see the mark as unusual? What if they don’t care if they have a mark on their body?


Why is self-recognition needed for self-awareness? Couchman (see citation below) looked at self-awareness in rhesus monkeys using a sense of self-agency instead of self-recognition.

Of the many species that fail the mirror self-recognition task, rhesus monkeys (Macaca mulatta) are particularly interesting because their failures are probably not owing to cognitive factors, but rather social tendencies to make threat gestures towards any monkey image. … In all of these tasks (testing metacognition), rhesus monkeys know what they know and what they do not know, suggesting that they have some awareness of their own mental states. … one potential way to resolve the conflicting results in mirror self-recognition and uncertainty-monitoring is to create a task in which subjects are asked to identify their own self-generated actions. Such a task would tap the cognitive and sensorimotor cues involved in self-monitoring, self-agency and self-awareness, while eliminating distracting self-images. The current task asks humans and monkeys, for the first time, to distinguish between self-controlled and partially directionally reversed (distractor) cursors that are equally perceptually salient. If monkeys have any sense of self-agency, they ought to be able to distinguish self-generated from partially altered actions.


By these other tests rather than the mirror test, rhesus monkeys show themselves to be self-aware. So the mirror test should not be the gold standard of self-awareness – it is not the one and only test.


Here is the abstract:

Rhesus monkeys (Macaca mulatta) have shown the ability to monitor their own mental states, but fail the mirror self-recognition test. In humans, the sense of self-agency is closely related to self-awareness, and results from monitoring the relationship between intentional, sensorimotor and perceptual information. Humans and rhesus monkeys were trained to move a computer icon with a joystick while a distractor icon partially matched their movements. Both humans and monkeys were able to monitor and identify the icon they were controlling, suggesting they have some understanding of self-agency.

Justin J. Couchman (2012). Self-agency in rhesus monkeys Biol. Lett. DOI: 10.1098/rsbl.2011.0535

It is official

What has been known/suspected for many years is now accepted science – consciousness is not unique to humans. On July 7 the Cambridge Declaration on Consciousness was signed by a group of recognized authorities (cognitive neuroscientists, neuropharmacologiests, neurophysiologists, neuroanatomist and computational neuroscientists). They were the attentees at the Francis Crick Memorial Conference on Consciousness in Human and non-Human Animals. The document was presented by Philip Low, David Edelmann and Christof Koch and was signed by all participants at the conference. They declared:

“The absence of a neocortex does not appear to preclude an organism from experiencing affective states. Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”


We have tool using, problem solving, and planning out of the way and now consciousness, so perhaps we can stop thinking that humans are so very, very difference from the rest of the animals. It is far more useful to be finding the evolutionary continuums between humans and other animals, rather than trying to find ways that we are unique. Of course we are unique in the sense that each-and-all species are unique. That is a trivial question of definition; species differ significantly from one another. But we are not uniquely unique. Everything we have must have a roots and commonalities in other primates. Accept it and use it to obtain a better understanding of ourselves.

Addition: thank you, Henk Poley, for your comment and link which I have brought up to the level of the post  -

 A direct link would have been nice:


Those doggy-people

Those doggy-people keep saying that dogs are special and they communicate with their dogs who have feelings similar to their own. Non-doggy-people just shake their heads. With a few caveats, I’m with the doogy-people.

People differ and so do dogs. Some dogs are unbelievably dumb or uninterested in their human companions or just uncooperative. At the other end of the scales, there are some very smart dogs, some very caring dogs and some dogs very willing to please. I just read a review of an article (Hecht 2012 Behavioral assessment and owner perceptions of behaviors associated with guilt in dogs. Appl. Anim. Behav. Sci.) about whether dogs show guilt, and kept thinking about a dog I had that was just plain sneaky, always playing games of deception. That dog would never let on that she had done something wrong. We might be able to guess that something was amiss if she was exceptionally friendly in a carefree manner. I would think, what is she hiding? Of course, she looked contrite when she was caught red-handed but that was just to shorten her scolding. Now, of course, I know that this description, if anything, makes the dog appear more human-like then a similar description of a dog that appears to show guilt. The point I am making is that dogs are a very mixed lot. I have known dogs that followed where I was pointing and dogs that didn’t. I have had dogs that understand many words and ones that only had a handful. Some dogs are jealous, some not, and so on.

But there are three reasons to assume (as much as is reasonable for any particular dog) that they have similar emotions, moods. signals etc. to ourselves. The first reason is that all mammals have similar brain types, hormones, sense organs and so on. We have to have a reasons to assume that they work differently from humans, not reasons to think they work the same. So if they look guilty than the starting point should be that they are feeling guilty. We might (and do) want to check that assumption, but it is only good physiology to start with the assumption of similarity.

The second reason we are reasonable in assuming dogs are similar to us is that we have lived together long enough to have developed over that time behaviours that work for both dogs and humans. We could have bred dogs that had the capacity to some small amount of guilt if they did not start out with any.

But the third reason is different. We humans are better at dealing with others if we use the system that comes naturally to us. We are social animals and have ways of understanding each other. It is simply easier to understand a dog if they view dogs as similar to people, than it is to view it as unlike anything else, a black box machine-like thingy. This idea was well said by a sheepdog trialer quoted in a post by Greg Downey on Paul Keil’s work (here). There is a lot in this post and it is well worth following the link to read the rest and look at the video clips.

In the demonstration for Paul, Damian (the trialer) intentionally gave Whiskey (the dog) a bad command, encouraging the dog to move in a way that was likely to cause the sheep to bolt out of control. After the sheep got loose, Damian described his interaction with Whiskey: I made the dog come around this way [clockwise around the mob of three sheep]. He said, ‘They’re gonna get away.’ He didn’t want to come. He said, ‘I think it’s a bad call.’ And I argued with him, and I said, ‘No. Come!’ And he said, ‘Nah nah… I tell you, they’re gonna go.’ And then he started to come, and the sheep started to go, and then he went, ‘See, I told ya’…

Of course, at no time did Whiskey actually speak to Damian. And Damian’s signals were whistles, shouts, and gestures, much simpler than the elaborate interpretation that Damian offered in his post-interaction analysis… Damian was explaining his perceptions of his dog’s thoughts as the two of them, together, interacted with three other animals, the sheep.

While Damian’s recollection was no doubt intentionally anthropomorphised, and possibly better elaborated than usual – giving the dog a voice – because of the sympathetic audience, the interaction that had occurred only minutes earlier was far more complex than a novice like Paul could recognise. Sure, Paul heard Damian give the command and witnessed the sheepdog’s momentary hesitation to follow, but he thought little about it; Damian’s description revealed a reciprocal exchange, a negotiation between human and dog based upon each one’s perceptions of the sheep and their spatial and emotional relations. Paul was simply not privy to a lot of the detail of their communication because he couldn’t see it. Whiskey was a far more sophisticated social agent then Paul could initially grasp…

The dog was not simply a tool, or merely obedient to a guiding human intelligence; on some level, Whiskey grasped what needed to be done, and Damian had come to count on the dog’s ability to herd, including the dog’s perception of how stressed and liable to flight the sheep were. The key to being an expert dog trialer, then, included the ability, not just to train a dog to herd, but to perceive the dog’s intentions and perceptions, and to anticipate the animal’s next move (as well as those of the sheep)…

Being an expert at interacting with dogs not only means a brain that’s better attuned to how dogs communicate; in fact, experts and non-experts, in most respects, are quite similar. Expertise means having behaviour patterns that include knowing where to search the animal’s body for information and greater tendency to ‘mentalise’ or impute motives to the animals (whether those projections are accurate is a separate question)…

That is, anthropomorophism may not be neurologically or biologically accurate, but it may be cognitively and practically useful, helping handlers to projectively scenario-build as they interact with their sheep and dogs (who are also engaged in their own cognitive forms of anticipation and negotiation with each other). Part of ‘thinking like a dog’ or a sheep may be inaccurately assuming that dogs and sheep are ‘thinking like an (admittedly odd or not terribly bright) four-legged human.’…Trialers would be the first to admit that the minds of sheep and dog are not the same as that of humans. They believe anthropomorphising the animals is a grave mistake. Most veteran trialers believe that the boundary between dogs and humans is wide and should not be blurred, or the dogs’ performance will suffer.

Still, even sheepdog trialers who are acutely aware of their dogs’ limits attribute internal mental states and dispositions such as ‘confidence,’ ‘beliefs,’ and ‘thoughts,’ not hesitating to project human-like cognitive events to their animals. If humans recruit the same socio-cognitive, neurological mechanisms they use with fellow humans to engage in the same kinds of interactions with other organisms, the overlap between folk psychological language for animals and humans should not be surprising. That is, if we’re using the same equipment to perceive a dog’s or sheep’s intentions as that we use to figure out what each other are thinking, anthropomorphizing is likely, even in old-school dog trialers who have strictly instrumental relations with their dogs and sheep, much more so than most people with their companion animals.

Of course, if folk psychological language suggests we’re using the same cognitive or neurological mechanisms we use for reading humans, we would expect a degree of anthropomorphic ‘overshoot.’ Cognitive overlap in the ability to perceive animal intentionality would likely lead us to over-estimate the nonhuman animal’s capacities, over-anthropomorphising their cognition.

Sheepdog trials and that ‘man-sheep-dog’ configuration remind us that humans do not face other animals alone. Let’s not forget the dogs. As Shipman has pointed out, dogs are special. When our ancestors and the ancestors of dogs came into contact, two species with extraordinary social skills, and surprisingly similar pack hunting strategies, began a long relationship that arguably shaped the evolution of both over the next thousands of years. … Dogs may be ‘overshooting’ their attribution of dog-like responses when they interact with us. … Do dogs bring their own canine-morphistic tendencies to relationships with humans and other animals?

Whether their ‘readings’ of the animals’ states are accurate is less important than the fact that both species communicate in predictable, useful ways so that they can work together, anticipate each others’ actions, and live in stable inter-species communities.

But I have to say that if a model works well and is useful, it is unlikely to be completely wrong. When anthropomorphism works very well (as it does with dogs) then it is probably somewhat accurate. I am very inclined to view my dog as a conscious animal with similar emotions and low-voltage but similar thinker.

Animal metacognition

Metacognition, thinking about thinking, is sometimes said to distinguish humans from other animals. It seems that dolphins and some primates, at least, are capable of metacognition. This is reported in a press release from the University of Buffalo, carried by ScienceDaily (here).

Smith and his colleagues provide a comprehensive review of the current state of the animal-metacognition literature. They describe how Smith inaugurated animal metacognition as a new field of study in 1995 with research on a bottlenosed dolphin. The dolphin assessed correctly when the experimenter’s trials were too difficult for him, and adaptively declined to complete those trials. The dolphin also showed his own distinctive set of hesitation, wavering and worrying behaviors when the trials were too difficult. In sharp contrast, when the trials were easy, he swam to the responses so fast that he would make a bow-wave around himself that would swamp Smith’s delicate electronics.

Subsequently, Smith and many collaborators also explored the metacognitive capacities of joystick-trained macaques. These Old-World monkeys, native to Africa and Asia, can make specific responses to declare uncertainty about their memory. They can respond, “Uncertain,” to gain hints from the experimenters of what to do on the first trial of new tasks. They can even respond, “Uncertain,” when their memory has been erased by trans-cranial magnetic stimulation… supports the consensus that animals share with humans a form of the self-reflective, metacognitive capacity. “In all respects,” says Smith, “their capacity for uncertainty monitoring, and for responding to uncertainty adaptively, show close correspondence to the same processes in humans.


Quantity has a quality all its own“, which Stalin may or may not have said, is worth thinking about. Many inquiries start with a qualitative difference between man and other animals. This all-important difference is searched for and guessed at. The effort to find the unique x has disrupted and distorted the normal scientific path. On the other hand, quantitative differences between us and other species is a much more fruitful objective to search for.

Here is a quote from Marc Bekoff in a recent post (here):

For as long as human animals have pondered how we might differ from nonhuman animals (hereafter animals for convenience) many ideas have come and gone. For example, it’s been postulated that humans are created in the image of God and are the only rational beings. People vary in their opinions on whether we are the only animals who are created in the image of God and of course it’s not a claim that can be proven or disproven. However, ample research has shown that animals are rational beings and that they also share with us many other traits that were once thought to be uniquely human, including manufacturing and using tools, having culture, having a sense of self, using complex systems of communication, producing art, and having rich and deep emotional lives and knowing right from wrong. Two traits that seem to separate us from other animals are we’re the only animals who cook food and no other animals are as destructive and evil…

The time has come to debunk the myth of human exceptionalism once and for all. It’s a hollow, shallow, and self-serving perspective on who we are. Of course we are exceptional in various arenas as are other animals. Perhaps we should replace the notion of human exceptionalism with species exceptionalism, a move that will force us to appreciate other animals for who they are, not who or what we want them to be.

Separating how we think about humans and other animals is like separating how we think about rivers and the Nile. It is not an efficient way to understand the Nile and it robs effort from understanding rivers in general. The only way this sort of thing happens if we start with “the Nile is not a river”, “don’t use concepts that describe the Nile for any other river (nilomorphism to coin a word)” or “it belittles the Great Nile to say it behaves like other rivers”. We have built an artificial boundary here, we have not ‘divided nature at its joints’. We will sink down to playing semantic games – trying to define Nile so other rivers are not included and trying to define river so that it includes them all except for the Nile. In the same way, dividing man from other animals is also artificial – not the way science should be done.

Human uniqueness has been a sort of holy grail. People have been searching for this mythical piece of knowledge – what is the important distinction. But the important knowledge is the ability to trace how all those things that we share with the other animals have been mixed and modified to produce the unexceptional uniqueness of all animal species. No part of our makeup and our culture started from nothing; everything (gene, gene-like, meme or meme-like) has evolved to its present state; it had evolutionary roots. Science should not be trying to separate us from other animals but should be drawing the connections. By and large Biology has been doing this for years but with the newer brain sciences it has been tough trying to break through the mind-set that humans are unique in a unique way.


Deliver me from bullshit

A blog posting has made me angry. As I have said before, I dislike reading angry posts and try to avoid writing them myself. But there is a limit and so here I am writing an angry post. Below is the start of a blog on the Psychology Today site in its Sapient Nature blog.

Human beings are different from other, lower-order, animals in several ways. Humans are the only species with the ability to imagine, which allows us to “time travel” (that is, reminisce about past events and imagine future ones) and to conceive of things (products, ideas) that currently don’t exist. We are also the only species to be aware that we are going to die, which, according to some psychologists, is the primary reason we have traditions and culture.

A third way in which we are different from others species is that we are the only ones to feel the need to be busy. Most lower-order animals would presumably be perfectly satisfied to idle their time away. Give a lower-order animal sufficient quantities of food, love, and shelter, and the animal will likely grow to be fat and happy; the animal would have no issues about lazing around and frittering away the rest of its life.

The writer than carries on with a reasonable post on human reactions to boredom. He even quotes evidence for what he says about human boredom. (here) Well done - if you ignore the start of the post.

Why then the first two paragraphs? As they have nothing to do with the main idea of the post, I assume they are a literary flourish. I do not think that it is reasonable to say any-old-dumb-thing just to try to be an interesting writer. Not if you then want to be taken seriously in your third paragraph.

There is a definition of bullshit saying it is not really a lie and its truthfulness is not the point. The speaker of bullshit does not care if what he says is true, sometimes it is and sometimes it’s not. The bullshitter does not even care if you believe him. It is the overall impression that counts. I don’t get the feeling that the blogger cares whether I believe what he has to say about animals. He makes no attempt to convince me – no science, no anecdotes, no logic, no folk wisdom. Of course, there are ideas that are so accepted and acceptable in particular contexts that they need no support. But here we have a PhD in psychology who teaches in a university and edits journals, writing in a prominent psychology site. He should (and probably does) know what statements need support and what do not.

What animals think does not have a single answer. After all ‘animals’ includes everything from sponges to us. But definitely it includes other primates, dogs, elephants, whales and dolphins, crows and parrots. The author is saying, with a straight face, that these particular animals as well as many others (1) cannot imagine (2) do not foretell death (3) do not feel boredom. The death remark is not obviously false, probably even true, but also probably not the primary cause of anything so important as culture. The other two remarks are controversial at best and unacceptable at worst. Some people would accept them but many wouldn’t. I wouldn’t. In previous postings I have dealt with various aspects of animal thought so I am not going to repeat them here. The point I am making is that the area is controversial and therefore bold sweeping statements cannot be made without some support.

But for bullshit none of this matters. It was the bullshit that made me mad. If I thought that the writer actually believed his first two paragraphs were about anything except setting a tone for the rest of the post, I would have disagreed but not felt angry. I have a vision of the author thinking about how to make a piece about boredom interesting. They can’t think of anything original so they use the ‘only humans can x’ hook. That should make readers feel warm inside. They know that a great many ‘only humans can x’ have been discredited but does that matter. No need to look this one up – their readers will not care. Well I do. And if I was a zoo keeper who spend hours every day trying to keep the animals from going stir-crazy, I would care even more.


Worms and us

ScienceDaily reports on a recent paper in Cell by R. Tomer and group (here) looks at the similarities between the vertebrate cortex and the mushroom bodies in insects and marine worms.

He developed a new technique, called cellular profiling by image registration (PrImR), which is the first to enable scientists to investigate a large number of genes in a compact brain and determine which are turned on simultaneously. This technique enabled Tomer to determine each cell’s molecular fingerprint, defining cell types according to the genes they express, rather than just based on their shape and location as was done before.

Using this new method, they found similarities that imply an evolutionary common ancestor (rather than independent evolution) of mushroom bodies and the pallium (cerebral cortex). The common ancestor would be living about 600 million years ago.

As well as having the similar cell types, developing in a similar way, it is interesting that mushroom bodies and palliums have similar functions.

This ancestral structure was likely a group of densely packed cells, which received and processed information about smell and directly controlled locomotion. It may have enabled our ancestors crawling over the sea floor to identify food sources, move towards them, and integrate previous experiences into some sort of learning.

It appears that the general pattern is: taking in sensory information and integrating it in sensory-associative areas, using this ‘perception’ to orientate movement, and learning/remembering its environment. This part of various brains is a good candidate to product whatever amount or degree of consciousness the animal possesses.

The brains of birds

ScienceDaily reports on work by Y. Wang and others (here) which compares the mammalian neo-cortex with structures in the brains of birds.

For more than a century, neuroscientists believed that the brains of humans and other mammals differed from the brains of other animals, such as birds (and so were presumably better). This belief was based, in part, upon the readily evident physical structure of the neocortex, the region of the brain responsible for complex cognitive behaviors.

Specifically, the mammalian neocortex features layers of cells (lamination) connected by radially arrayed columns of other cells, forming functional modules characterized by neuronal types and specific connections. Early studies of homologous regions in nonmammalian brains had found no similar arrangement, leading to the presumption that neocortical cells and circuits in mammals were singular in nature.

For 40 years, Karten and colleagues have worked to upend this thinking. In the latest research, they used modern, sophisticated imaging technologies, including a highly sensitive tracer, to map a region of the chicken brain (part of the telencephalon) that is similar to the mammalian auditory cortex. Both regions handle listening duties. They discovered that the avian cortical region was also composed of laminated layers of cells linked by narrow, radial columns of different types of cells with extensive interconnections that form microcircuits that are virtually identical to those found in the mammalian cortex.

The findings indicate that laminar and columnar properties of the neocortex are not unique to mammals, and may in fact have evolved from cells and circuits in much more ancient vertebrates.

This has several ramifications. In vertebrates, different species have brains that differ more in degree and less in kind and therefore simpler brains may be very useful experimental subjects. They may be easier to work with by still give valuable insights. It also weakens the taboo on anthropomorphism. If it acts like cognition – it may be cognition. And finally there is nothing like two different examples of the same principle to find the important aspects of the principle. In trying to understand how the neo-cortex module functions it is useful to have the mammal and bird versions to compare. And consciousness need not be thought of as strictly a mammal thing just because in mammals it involves the neo-cortex.