Animal consciousness

"Animal sentience" redirects here. For the journal, seeAnimal Sentience(journal).

Animal consciousness,oranimal awareness,is thequalityor state of self-awareness within an animal, or of being aware of an external object or something within itself.In humans,consciousnesshas been defined as:sentience,awareness,subjectivity,qualia,the ability toexperienceor tofeel,wakefulness,having a sense ofselfhood,and the executive control system of the mind.Despite the difficulty in definition, many philosophers believe there is a broadly shared underlying intuition about what consciousness is.

According to theCambridge Declaration on Consciousness,"near human-like levels of consciousness" have been observed in thegrey parrot.

The topic of animal consciousness is beset with a number of difficulties. It poses theproblem of other mindsin an especially severe form because animals, lacking the ability to usehuman language,cannot communicate their experiences.It is also difficult to reason objectively about the question because a denial that an animal is conscious is often taken to imply that they do not feel, their life has no value, and that harming them is not morally wrong.For example, the 17th-century French philosopherRené Descartesis sometimes criticised for providing a rationale for the mistreatment of animals because he argued that only humans are conscious.

Philosophers who consider subjective experience the essence of consciousness also generally believe, as a correlate, that the existence and nature of animal consciousness can never rigorously be known. The American philosopherThomas Nagelspelled out this point of view in an influential essay titledWhat Is it Like to Be a Bat?He said that an organism is conscious "if and only if there is something that it is like to be that organism—something it is likeforthe organism "; and he argued that no matter how much we know about an animal's brain and behavior, we can never really put ourselves into the mind of the animal and experience their world in the way they do themselves.Other thinkers, such as the cognitive scientistDouglas Hofstadter,dismiss this argument as incoherent.Several psychologists and ethologists have argued for the existence of animal consciousness by describing a range of behaviors that appear to show animals holding beliefs about things they cannot directly perceive—Walter Veit's 2023 bookA Philosophy for the Science of Animal Consciousnessreviews a substantial portion of the evidence.

Animal consciousness has been actively researched for over one hundred years.In 1927, the American functional psychologistHarvey Carrargued that any valid measure or understanding of awareness in animals depends on "an accurate and complete knowledge of its essential conditions in man".A more recent review concluded in 1985 that "the best approach is to use experiment (especially psychophysics) and observation to trace the dawning and ontogeny of self-consciousness, perception, communication, intention, beliefs, and reflection in normal human fetuses, infants, and children".In 2012, a group of neuroscientists signed theCambridge Declaration on Consciousness,which "unequivocally" asserted 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 neural substrates."

Philosophical background

René Descartes argued that only humans are conscious, and not other animals.

Themind–body problemin philosophy examines the relationship betweenmindandmatter,and in particular the relationship betweenconsciousnessand the brain. A variety of approaches have been proposed. Most are eitherdualistormonist.Dualism maintains a rigid distinction between the realms of mind and matter. Monism maintains that there is only one kind of stuff, and that mind and matter are both aspects of it. The problem was addressed by pre-Aristotelianphilosophers,and was famously addressed byRené Descartesin the 17th century, resulting inCartesian dualism.Descartes believed that humans only, and not other animals have this non-physical mind.

The rejection of the mind–body dichotomy is found in FrenchStructuralism,and is a position that generally characterized post-warFrench philosophy. The absence of an empirically identifiable meeting point between the non-physical mind and its physical extension has proven problematic to dualism and many modern philosophers of mind maintain that the mind is not something separate from the body.These approaches have been particularly influential in the sciences, particularly in the fields ofsociobiology,computer science,evolutionary psychology,and theneurosciences.

Epiphenomenalism

Main article:Epiphenomenalism

Epiphenomenalism is the theory inphilosophy of mindthat mental phenomena are caused by physical processes in the brain or that both are effects of a common cause, as opposed to mental phenomena driving the physical mechanics of the brain. The impression that thoughts, feelings, or sensations cause physical effects, is therefore to be understood as illusory to some extent. For example, it is not the feeling of fear that produces an increase in heart beat, both are symptomatic of a common physiological origin, possibly in response to a legitimate external threat.

The history of epiphenomenalism goes back to the post-Cartesian attempt to solve the riddle ofCartesian dualism,i.e., of how mind and body could interact.La Mettrie,LeibnizandSpinozaall in their own way began this way of thinking. The idea that even if the animal were conscious nothing would be added to the production of behavior, even in animals of the human type, was first voiced by La Mettrie (1745), and then byCabanis(1802), and was further explicated byHodgson(1870) andHuxley(1874).Huxley (1874) likened mental phenomena to the whistle on a steam locomotive. However, epiphenomenalism flourished primarily as it found a niche among methodological or scientific behaviorism. In the early 1900sscientific behavioristssuch asIvan Pavlov,John B. Watson,andB. F. Skinnerbegan the attempt to uncover laws describing the relationship between stimuli and responses, without reference to inner mental phenomena. Instead of adopting a form ofeliminativismor mentalfictionalism,positions that deny that inner mental phenomena exist, a behaviorist was able to adopt epiphenomenalism in order to allow for the existence of mind. However, by the 1960s, scientific behaviourism met substantial difficulties and eventually gave way to thecognitive revolution.Participants in that revolution, such asJerry Fodor,reject epiphenomenalism and insist upon the efficacy of the mind. Fodor even speaks of "epiphobia" —fear that one is becoming an epiphenomenalist.

Thomas Henry Huxleydefends in an essay titledOn the Hypothesis that Animals are Automata, and its Historyan epiphenomenalist theory of consciousness according to which consciousness is a causally inert effect of neural activity— "as the steam-whistle which accompanies the work of a locomotive engine is without influence upon its machinery".To thisWilliam Jamesobjects in his essayAre We Automata?by stating an evolutionary argument for mind-brain interaction implying that if the preservation and development of consciousness in the biological evolution is a result ofnatural selection,it is plausible that consciousness has not only been influenced by neural processes, but has had a survival value itself; and it could only have had this if it had been efficacious.Karl Popperdevelops in the bookThe Self and Its Braina similar evolutionary argument.

Animal ethics

Bernard Rollinof Colorado State University, the principal author of two U.S. federal laws regulating pain relief for animals, writes that researchers remained unsure into the 1980s as to whether animals experience pain, and veterinarians trained in the U.S. before 1989 were simply taught to ignore animal pain.In his interactions with scientists and other veterinarians, Rollin asserts that he was regularly asked to prove animals are conscious and provide scientifically acceptable grounds for claiming they feel pain.The denial of animal consciousness by scientists has been described asmentophobiaby Donald Griffin.Academic reviews of the topic are equivocal, noting that the argument that animals have at least simple conscious thoughts and feelings has strong support,but some critics continue to question how reliably animal mental states can be determined.A refereed journalAnimal Sentiencelaunched in 2015 by the Institute of Science and Policy ofThe Humane Society of the United Statesis devoted to research on this and related topics.

Defining consciousness

About forty meanings attributed to the termconsciousnesscan be identified and categorized based onfunctionsandexperiences.The prospects for reaching any single, agreed-upon, theory-independent definition of consciousness appear remote.

Consciousness is an elusive concept that presents many difficulties when attempts are made to define it.Its study has progressively become an interdisciplinary challenge for numerous researchers, including ethologists, neurologists, cognitive neuroscientists, philosophers, psychologists and psychiatrists.

In 1976,Richard Dawkinswrote, "The evolution of the capacity to simulate seems to have culminated in subjective consciousness. Why this should have happened is, to me, the most profound mystery facing modern biology."In 2004, eight neuroscientists felt it was still too soon for a definition. They wrote an apology in "Human Brain Function",in which they stated:

"We have no idea how consciousness emerges from the physical activity of the brain and we do not know whether consciousness can emerge from non-biological systems, such as computers... At this point the reader will expect to find a careful and precise definition of consciousness. You will be disappointed. Consciousness has not yet become a scientific term that can be defined in this way. Currently we all use the termconsciousnessin many different and often ambiguous ways. Precise definitions of different aspects of consciousness will emerge... but to make precise definitions at this stage is premature. "

Consciousnessis sometimes defined as the quality or state of being aware of an external object or something within oneself.It has been defined somewhat vaguely as:subjectivity,awareness,sentience,the ability toexperienceor tofeel,wakefulness, having a sense ofselfhood,and the executive control system of the mind.Despite the difficulty in definition, many philosophers believe that there is a broadly shared underlying intuition about what consciousness is.Max Velmansand Susan Schneider wrote inThe Blackwell Companion to Consciousness:"Anything that we are aware of at a given moment forms part of our consciousness, making conscious experience at once the most familiar and most mysterious aspect of our lives."

Related terms, also often used in vague or ambiguous ways, are:

• Awareness:the state or ability to perceive, to feel, or to beconsciousof events,objects,or sensorypatterns.In this level of consciousness, sense data can be confirmed by an observer without necessarily implyingunderstanding.More broadly, it is the state or quality of being aware of something. Inbiological psychology,awareness is defined as a human's or an animal'sperceptionandcognitivereaction to a condition or event.
• Self-awareness:the capacity forintrospectionand the ability to reconcile oneself as an individual separate from the environment and other individuals.
• Self-consciousness:an acute sense of self-awareness. It is a preoccupation with oneself, as opposed to the philosophical state ofself-awareness,which is the awareness that one exists as an individual being; although some writers use both terms interchangeably or synonymously.
• Sentience:the ability to be aware (feel,perceive,or beconscious) of one's surroundings or to have subjective experiences. Sentience is a minimalistic way of defining consciousness, which is otherwise commonly used to collectively describe sentience plus other characteristics of the mind.
• Sapience:often defined as wisdom, or the ability of an organism or entity to act with appropriatejudgment,a mental faculty which is a component ofintelligenceor alternatively may be considered an additional faculty, apart from intelligence, with its own properties.
• Qualia:individual instances ofsubjective,conscious experience.

Sentience (the ability to feel, perceive, or to experience subjectivity) is not the same as self-awareness (being aware of oneself as an individual). Themirror testis sometimes considered to be an operational test for self-awareness, and the handful of animals that have passed it are often considered to be self-aware.It remains debatable whether recognition of one's mirror image can be properly construed to imply full self-awareness,particularly given that robots are being constructed which appear to pass the test.

Much has been learned in neuroscience about correlations between brain activity and subjective, conscious experiences, and many suggest that neuroscience will ultimately explain consciousness; "...consciousness is a biological process that will eventually be explained in terms of molecular signaling pathways used by interacting populations of nerve cells...".However, this view has been criticized because consciousness has yet to be shown to be a process,and the so-called"hard problem"of relating consciousness directly to brain activity remains elusive.

Scientific approaches

SinceDescartes's proposal ofdualism,it became general consensus that the mind had become a matter ofphilosophyand that science was not able to penetrate the issue of consciousness – that consciousness was outside of space and time. However, in recent decades many scholars have begun to move toward a science of consciousness.Antonio DamasioandGerald Edelmanare two neuroscientists who have led the move to neural correlates of the self and of consciousness. Damasio has demonstrated that emotions and their biological foundation play a critical role in high level cognition,and Edelman has created a framework for analyzing consciousness through a scientific outlook. The current problem consciousness researchers face involves explaining how and why consciousness arises from neural computation.In his research on this problem, Edelman has developed a theory of consciousness, in which he has coined the termsprimary consciousnessandsecondary consciousness.

Eugene Linden,author ofThe Parrot's Lamentsuggests there are many examples of animal behavior and intelligence that surpass what people would suppose to be the boundary of animal consciousness. Linden contends that in many of these documented examples, a variety of animal species exhibit behavior that can only be attributed to emotion, and to a level of consciousness that we would normally ascribe only to our own species.

PhilosopherDaniel Dennettcounters:

Consciousness requires a certain kind of informational organization that does not seem to be 'hard-wired' in humans, but is instilled by human culture. Moreover, consciousness is not a black-or-white, all-or-nothing type of phenomenon, as is often assumed. The differences between humans and other species are so great that speculations about animal consciousness seem ungrounded. Many authors simply assume that an animal like a bat has a point of view, but there seems to be little interest in exploring the details involved.

Consciousness in mammals (including humans) is an aspect of the mind generally thought to comprise qualities such assubjectivity,sentience,and the ability toperceivethe relationship betweenoneselfand one'senvironment.It is a subject of much research inphilosophy of mind,psychology,neuroscience,andcognitive science.Some philosophers divide consciousness intophenomenalconsciousness, which is subjective experience itself, and access consciousness, which refers to the global availability of information to processing systems in the brain.Phenomenal consciousness has many different experienced qualities, often referred to asqualia.Phenomenal consciousness is usually consciousnessofsomething oraboutsomething, a property known asintentionalityin philosophy of mind.

In humans, there are three common methods of studying consciousness: verbal reporting, behavioural demonstrations, and neural correlation with conscious activity, though these can only be generalized to non-human taxa with varying degrees of difficulty.In a new study conducted inrhesus monkeys,Ben-Haim and his team used a process dissociation approach that predicted opposite behavioral outcomes for the two modes of perception. They found that monkeys displayed exactly the same opposite behavioral outcomes as humans when they were aware or unaware of the stimuli presented.

Mirror test

Elephants can recognize themselves in a mirror.

External videos
Self-recognition in apes –National Geographic

Main article:Mirror test

The sense in which animals (or human infants) can be said to haveconsciousnessor aself-concepthas been hotly debated; it is often referred to as the debate over animal minds. The best known research technique in this area is themirror testdevised byGordon G. Gallup,in which the skin of an animals (or human infant) is marked, while they are asleep or sedated, with a mark that cannot be seen directly but is visible in a mirror. The animals are then allowed to see their reflection in a mirror; if the animal spontaneously directs grooming behaviour towards the mark, that is taken as an indication that they are aware of themselves.Over the past 30 years, many studies have found evidence that animals recognise themselves in mirrors. Self-awareness by this criterion has been reported for:

• Land mammals:apes(chimpanzees,bonobos,orangutansandgorillas)andelephants.
• Cetaceans:bottlenose dolphins,killer whalesand possiblyfalse killer whales.
• Birds:magpiesandpigeons(can pass the mirror test after training in the prerequisite behaviors).

Until recently, it was thought that self-recognition was absent in animals without aneocortex,and was restricted to mammals with large brains and well-developed social cognition. However, in 2008, a study of self-recognition incorvidsreported significant results for magpies. Mammals and birds inherited the same brain components from their last commonancestornearly 300 million years ago, and have since independently evolved and formed significantly different brain types. The results of the mirror and mark tests showed that neocortex-lessmagpiesare capable of understanding that a mirror image belongs to their own body. The findings show that magpies respond in the mirror and mark tests in a manner similar to apes, dolphins and elephants. The magpies were chosen to study based on their empathy and lifestyle, a possible precursor to their ability to develop self-awareness.For chimpanzees, the occurrence is about 75% in young adults and considerably less in young and old individuals.For monkeys, non-primate mammals, and a number of bird species, exploration of the mirror and social displays were observed. Hints at mirror-induced self-directed behavior have been obtained.

According to a 2019 study,cleaner wrasseshave become the first fish ever observed to pass the mirror test.However, the test's inventor Gordon Gallup has said that the fish were most likely trying to scrape off a perceived parasite on another fish and that they did not demonstrate self-recognition. The authors of the study retorted that because the fish checked themselves in the mirror before and after the scraping, this meant that the fish had self-awareness and recognized that their reflections belonged to their own bodies.

The mirror test has attracted controversy among some researchers because it is entirely focused on vision, the primary sense in humans, while other species rely more heavily on other senses such as theolfactorysense in dogs.A study in 2015 showed that the "sniff test of self-recognition (STSR)"provides evidence ofself-awarenessin dogs.

Language

External videos
Whale song–Oceania Project
This is Einstein!–Knoxville Zoo

See also:Animal language,Origin of language,Evolutionary linguistics,Talking bird,andFOXP2

Another approach to determine whether a non-human animal is conscious derives from passive speech research with a macaw (seeArielle). Some researchers propose that by passively listening to an animal's voluntary speech, it is possible to learn about the thoughts of another creature and to determine that the speaker is conscious. This type of research was originally used to investigate a child'scrib speechby Weir (1962) and in investigations of early speech in children by Greenfield and others (1976).

Zipf's lawmight be able to be used to indicate if a given dataset of animal communication indicate an intelligent natural language. Some researchers have used this algorithm to study bottlenose dolphin language.

Pain or suffering

See also:Pain in animalsandAnimal cruelty

Further arguments revolve around the ability of animals to feelpainorsuffering.Suffering implies consciousness. If animals can be shown to suffer in a way similar or identical to humans, many of the arguments against human suffering could then, presumably, be extended to animals. Others have argued that pain can be demonstrated by adverse reactions to negative stimuli that are non-purposeful or even maladaptive.One such reaction istransmarginal inhibition,a phenomenon observed in humans and some animals akin tomental breakdown.

Carl Sagan,the American cosmologist, points to reasons why humans have had a tendency to deny animals can suffer:

Humans – who enslave, castrate, experiment on, and fillet other animals – have had an understandable penchant for pretending animals do not feel pain. A sharp distinction between humans and 'animals' is essential if we are to bend them to our will, make them work for us, wear them, eat them – without any disquieting tinges of guilt or regret. It is unseemly of us, who often behave so unfeelingly toward other animals, to contend that only humans can suffer. The behavior of other animals renders such pretensions specious. They are just too much like us.

John Webster, a professor of animal husbandry at Bristol, argues:

People have assumed that intelligence is linked to the ability to suffer and that because animals have smaller brains they suffer less than humans. That is a pathetic piece of logic, sentient animals have the capacity to experience pleasure and are motivated to seek it, you only have to watch how cows and lambs both seek and enjoy pleasure when they lie with their heads raised to the sun on a perfect English summer's day. Just like humans.

However, there is no agreement where the line should be drawn between organisms that can feel pain and those that cannot.Justin Leiber,a philosophy professor atOxford Universitywrites that:

Montaigneis ecumenical in this respect, claiming consciousness for spiders and ants, and even writing of our duties to trees and plants.SingerandClarkeagree in denying consciousness to sponges. Singer locates the distinction somewhere between the shrimp and the oyster. He, with rather considerable convenience for one who is thundering hard accusations at others, slides by the case of insects and spiders and bacteria, they pace Montaigne, apparently and rather conveniently do not feel pain. The intrepidMidgley,on the other hand, seems willing to speculate about the subjective experience of tapeworms...Nagel... appears to draw the line at flounders and wasps, though more recently he speaks of the inner life of cockroaches.

There are also some who reject the argument entirely, arguing that although suffering animals feel anguish, a suffering plant also struggles to stay alive (albeit in a less visible way). In fact, no living organism 'wants' to die for another organism's sustenance. In an article written forThe New York Times,Carol Kaesuk Yoon argues that:

When a plant is wounded, its body immediately kicks into protection mode. It releases a bouquet of volatile chemicals, which in some cases have been shown to induce neighboring plants to pre-emptively step up their own chemical defenses and in other cases to lure in predators of the beasts that may be causing the damage to the plants. Inside the plant, repair systems are engaged and defenses are mounted, the molecular details of which scientists are still working out, but which involve signaling molecules coursing through the body to rally the cellular troops, even the enlisting of the genome itself, which begins churning out defense-related proteins... If you think about it, though, why would we expect any organism to lie down and die for our dinner? Organisms have evolved to do everything in their power to avoid being extinguished. How long would any lineage be likely to last if its members effectively didn't care if you killed them?

Cognitive bias and emotion

Is the glass half empty or half full?

See also:Cognitive bias in animalsandEmotion in animals

Cognitive bias in animals is a pattern of deviation in judgment, whereby inferences about other animals and situations may be drawn in an illogical fashion.Individuals create their own "subjective social reality" from their perception of the input.It refers to the question "Is the glass half empty or half full?",used as an indicator of optimism or pessimism. Cognitive biases have been shown in a wide range of species including rats, dogs, rhesus macaques, sheep, chicks, starlings and honeybees.

The neuroscientistJoseph LeDouxadvocates avoiding terms derived from human subjective experience when discussing brain functions in animals.For example, the common practice of callingbrain circuitsthat detect and respond to threats "fear circuits" implies that these circuits are responsible for feelings of fear. LeDoux argues that Pavlovian fear conditioning should be renamed Pavlovian threat conditioning to avoid the implication that "fear" is being acquired in rats or humans.Key to his theoretical change is the notion of survival functions mediated by survival circuits, the purpose of which is to keep organisms alive rather than to make emotions. For example, defensive survival circuits exist to detect and respond to threats. While all organisms can do this, only organisms that can be conscious of their own brain's activities can feel fear. Fear is a conscious experience and occurs the same way as any other kind of conscious experience: via cortical circuits that allow attention to certain forms of brain activity. LeDoux argues the only differences between an emotional and non-emotion state of consciousness are the underlying neural ingredients that contribute to the state.

Neuroscience

Drawing bySantiago Ramón y Cajal(1899) ofneuronsin the pigeon cerebellum

Neuroscienceis the scientific study of thenervous system.It is a highly activeinterdisciplinaryscience that collaborates with many other fields. The scope of neuroscience has broadened recently to includemolecular,cellular,developmental,structural,functional,evolutionary,computational,andmedicalaspects of the nervous system. Theoretical studies ofneural networksare being complemented with techniques forimagingsensory and motor tasks in thebrain. According to a 2008 paper, neuroscience explanations of psychological phenomena currently have a "seductive allure", and "seem to generate more public interest" than explanations which do not contain neuroscientific information.They found that subjects who were not neuroscience experts "judged that explanations with logically irrelevant neuroscience information were more satisfying than explanations without.

Neural correlates

See also:Neural correlates of consciousness

Theneural correlates of consciousnessconstitute the minimal set of neuronal events and mechanisms sufficient for a specific consciouspercept.Neuroscientists use empirical approaches to discoverneural correlatesof subjective phenomena.The set should beminimalbecause, if the brain is sufficient to give rise to any given conscious experience, the question is which of its components is necessary to produce it.

Visual sense and representation was reviewed in 1998 byFrancis CrickandChristof Koch.They concludedsensory neurosciencecan be used as a bottom-up approach to studying consciousness, and suggested experiments to test various hypotheses in this research stream.

A feature that distinguishes humans from most animals is that we are not born with an extensive repertoire of behavioral programs that would enable us to survive on our own ( "physiological prematurity"). To compensate for this, we have an unmatched ability to learn, i.e., to consciously acquire such programs by imitation or exploration. Once consciously acquired and sufficiently exercised, these programs can become automated to the extent that their execution happens beyond the realms of our awareness. Take, as an example, the incredible fine motor skills exerted in playing a Beethoven piano sonata or the sensorimotor coordination required to ride a motorcycle along a curvy mountain road. Such complex behaviors are possible only because a sufficient number of the subprograms involved can be executed with minimal or even suspended conscious control. In fact, the conscious system may actually interfere somewhat with these automated programs.

The growing ability of neuroscientists to manipulate neurons using methods from molecular biology in combination with optical tools depends on the simultaneous development of appropriate behavioural assays and model organisms amenable to large-scale genomic analysis and manipulation.A combination of such fine-grained neuronal analysis in animals with ever more sensitive psychophysical and brain imaging techniques in humans, complemented by the development of a robust theoretical predictive framework, will hopefully lead to a rational understanding of consciousness.

Neocortex and equivalents

Previously researchers had thought that patterns of neural sleep exhibited byzebra finchesneeded a mammalianneocortex.

Theneocortexis a part of the brain of mammals. It consists of thegrey matter,or neuronal cell bodies andunmyelinatedfibers, surrounding the deeperwhite matter(myelinatedaxons) in thecerebrum.The neocortex is smooth inrodentsand other small mammals, whereas inprimatesand other larger mammals it has deep grooves and wrinkles. These folds increase the surface area of the neocortex considerably without taking up too much more volume. Also, neurons within the same wrinkle have more opportunity for connectivity, while neurons in different wrinkles have less opportunity for connectivity, leading to compartmentalization of the cortex. The neocortex is divided intofrontal,parietal,occipital,andtemporallobes, which perform different functions. For example, the occipital lobe contains theprimary visual cortex,and the temporal lobe contains theprimary auditory cortex.Further subdivisions or areas of neocortex are responsible for more specific cognitive processes. The neocortex is the newest part of thecerebral cortexto evolve (hence the prefix "neo" ); the other parts of the cerebral cortex are thepaleocortexandarchicortex,collectively known as theallocortex.In humans, 90% of the cerebral cortex is neocortex.

Researchers have argued that consciousness in mammals arises in the neocortex, and therefore by extension used to argue that consciousness cannot arise in animals which lack a neocortex. For example, Rose argued in 2002 that the "fishes have nervous systems that mediate effective escape and avoidance responses to noxious stimuli, but, these responses must occur without a concurrent, human-like awareness of pain, suffering or distress, which depend on separately evolved neocortex."Recently that view has been challenged, and many researchers now believe that animal consciousness can arise fromhomologoussubcorticalbrain networks.For instance, evidence suggests thepalliuminbird brainsto be functionally equivalent to the mammalian cerebral cortex as a basis of consciousness.

Attention

Attentionis thecognitive processof selectively concentrating on one aspect of the environment while ignoring other things. Attention has also been referred to as the allocation of processing resources.Attention also has variations amongst cultures. Voluntary attention develops in specific cultural and institutional contexts through engagement in cultural activities with more competent community members.

Most experiments show that oneneural correlateof attention is enhanced firing. If a neuron has a certain response to a stimulus when the animal is not attending to the stimulus, then when the animal does attend to the stimulus, the neuron's response will be enhanced even if the physical characteristics of the stimulus remain the same. In many cases attention produces changes in theEEG.Many animals, including humans, producegamma waves(40–60 Hz) when focusing attention on a particular object or activity.

Extended consciousness

Extended consciousnessis an animal's autobiographical self-perception. It is thought to arise in the brains of animals which have a substantial capacity for memory and reason. It does not necessarily require language. The perception of a historic and future self arises from a stream of information from the immediate environment and from neural structures related to memory. The concept was popularised byAntonio Damasioand is used inbiological psychology.Extended consciousness is said to arise in structures in thehuman braindescribed asimage spacesanddispositional spaces.Image spaces imply areas wheresensoryimpressions of all types are processed, including the focused awareness of thecore consciousness.Dispositional spaces include convergence zones, which are networks in the brain where memories are processed and recalled, and where knowledge is merged with immediate experience.

Metacognition

Metacognitionis defined as "cognitionabout cognition ", or" knowing about knowing. "It can take many forms; it includes knowledge about when and how to use particular strategies for learning or for problem solving.It has been suggested that metacognition in some animals provides evidence for cognitive self-awareness.There are generally two components of metacognition: knowledge about cognition, and regulation of cognition.Writings on metacognition can be traced back at least as far asDe Animaand theParva Naturaliaof the Greek philosopherAristotle.Metacognologists believe that the ability to consciously think about thinking is unique tosapientspecies and indeed is one of the definitions of sapience.There is evidence thatrhesus monkeysand apes can make accurate judgments about the strengths of their memories of fact and monitor their own uncertainty,while attempts to demonstrate metacognition in birds have been inconclusive.A 2007 study provided some evidence for metacognition inrats,but further analysis suggested that they may have been following simpleoperant conditioningprinciples,or a behavioral economic model.

Mirror neurons

Mirror neuronsareneuronsthatfireboth when an animal acts and when the animal observes the same action performed by another.Thus, the neuron "mirrors" the behavior of the other, as though the observer were themselves acting. Such neurons have been directly observed inprimateand other species includingbirds.The function of the mirror system is a subject of much speculation. Many researchers in cognitive neuroscience and cognitive psychology consider that this system provides the physiological mechanism for the perception action coupling (see thecommon coding theory).They argue that mirror neurons may be important for understanding the actions of other people, and for learning new skills by imitation. Some researchers also speculate that mirror systems may simulate observed actions, and thus contribute totheory of mindskills,while others relate mirror neurons tolanguageabilities.Neuroscientists such as Marco Iacoboni (UCLA) have argued that mirror neuron systems in the human brain help us understand the actions and intentions of other people. In a study published in March 2005, Iacoboni and his colleagues reported that mirror neurons could discern if another person who was picking up a cup of tea planned to drink from it or clear it from the table. In addition, Iacoboni and a number of other researchers have argued that mirror neurons are the neural basis of the human capacity for emotions such asempathy.Vilayanur S. Ramachandranhas speculated that mirror neurons may provide the neurological basis of self-awareness.

Evolutionary psychology

See also:Evolutionary psychology

Consciousness is likely an evolvedadaptationsince it meetsGeorge Williams' criteria of species universality, complexity,and functionality, and it is atraitthat apparently increasesfitness.Opinions are divided as to where in biologicalevolutionconsciousness emerged and about whether or not consciousness has survival value. It has been argued that consciousness emerged (i) exclusively with the firsthumans,(ii) exclusively with the first mammals, (iii) independently in mammals and birds, or (iv) with the first reptiles.Donald Griffinsuggests in his bookAnimal Mindsa gradual evolution of consciousness.Each of these scenarios raises the question of the possible survival value of consciousness.

In his paper "Evolution of consciousness,"John Ecclesargues that special anatomical and physical adaptations of the mammaliancerebral cortexgave rise to consciousness.In contrast, others have argued that the recursive circuitry underwriting consciousness is much more primitive, having evolved initially in pre-mammalian species because it improves the capacity for interaction with both socialandnatural environments by providing an energy-saving "neutral" gear in an otherwise energy-expensive motor output machine.Once in place, this recursive circuitry may well have provided a basis for the subsequent development of many of the functions that consciousness facilitates in higher organisms, as outlined byBernard J. Baars.Richard Dawkinssuggested that humans evolved consciousness in order to make themselves the subjects of thought.Daniel Povinelli suggests that large, tree-climbing apes evolved consciousness to take into account one's own mass when moving safely among tree branches.Consistent with this hypothesis,Gordon Gallupfound thatchimpanzeesandorangutans,but not little monkeys or terrestrialgorillas,demonstratedself-awarenessin mirror tests.

The concept of consciousness can refer to voluntary action, awareness, or wakefulness. However, even voluntary behaviour involves unconscious mechanisms. Many cognitive processes take place in the cognitive unconscious, unavailable to conscious awareness. Some behaviours are conscious when learned but then become unconscious, seemingly automatic. Learning, especially implicitly learning a skill, can take place outside of consciousness. For example, plenty of people know how to turn right when they ride a bike, but very few can accurately explain how they actually do so.

Neural Darwinism

Main article:Neural Darwinism

Neural Darwinismis a large scale theory of brain function initially proposed in 1978 by the American biologistGerald Edelman.Edelman distinguishes between what he calls primary and secondary consciousness:

• Primary consciousness:is the ability, found in humans and some animals, to integrate observed events with memory to create anawarenessof the present and immediate past of the world around them. This form of consciousness is also sometimes called "sensory consciousness". Put another way, primary consciousness is the presence of varioussubjectivesensory contents of consciousness such assensations,perceptions,and mental images. For example, primary consciousness includes a person's experience of the blueness of the ocean, a bird's song, and the feeling of pain. Thus, primary consciousness refers to being mentally aware of things in the world in the present without any sense of past and future; it is composed of mental images bound to a time around the measurable present.
• Secondary consciousness:is an individual's accessibility to their history and plans. The concept is also loosely and commonly associated with having awareness of one's ownconsciousness.The ability allows its possessors to go beyond the limits of the remembered present ofprimary consciousness.

Primary consciousness can be defined as simple awareness that includesperceptionandemotion.As such, it is ascribed to most animals. By contrast, secondary consciousness depends on and includes such features as self-reflective awareness,abstract thinking,volitionandmetacognition.

Edelman's theory focuses on twonervous systemorganizations: thebrainstemandlimbic systemson one side and thethalamusandcerebral cortexon the other side. The brain stem and limbic system take care of essential body functioning and survival, while the thalamocortical system receives signals from sensory receptors and sends out signals to voluntary muscles such as those of the arms and legs. The theory asserts that the connection of these two systems during evolution helped animals learnadaptive behaviors.

Other scientists have argued against Edelman's theory, instead suggesting that primary consciousness might have emerged with the basic vegetative systems of the brain. That is, the evolutionary origin might have come from sensations and primal emotions arising fromsensorsandreceptors,both internal and surface, signaling that the well-being of the creature was immediately threatened—for example, hunger for air, thirst, hunger, pain, and extreme temperature change. This is based on neurological data showing thethalamic,hippocampal,orbitofrontal,insula,andmidbrainsites are the key to consciousness of thirst.These scientists also point out that the cortex might not be as important to primary consciousness as some neuroscientists have believed.Evidence of this lies in the fact that studies show that systematically disabling parts of the cortex in animals does not remove consciousness. Another study found that children born without a cortex are conscious. Instead of cortical mechanisms, these scientists emphasize brainstem mechanisms as essential to consciousness.Still, these scientists concede that higher order consciousness does involve the cortex and complex communication between different areas of the brain.

While animals withprimary consciousnesshave long-term memory, they lack explicit narrative, and, at best, can only deal with the immediate scene in the remembered present. While they still have an advantage over animals lacking such ability, evolution has brought forth a growing complexity in consciousness, particularly in mammals. Animals with this complexity are said to have secondary consciousness. Secondary consciousness is seen in animals withsemanticcapabilities, such as the fourgreat apes.It is present in its richest form in the human species, which is unique in possessing complexlanguagemade up ofsyntaxand semantics. In considering how the neural mechanisms underlying primary consciousness arose and were maintained during evolution, it is proposed that at some time around the divergence ofreptilesinto mammals and then intobirds,theembryologicaldevelopment of large numbers of new reciprocal connections allowed richre-entrantactivity to take place between the more posterior brain systems carrying out perceptual categorization and the more frontally located systems responsible for value-category memory.The ability of an animal to relate a present complex scene to their own previous history of learning conferred an adaptive evolutionary advantage. At much later evolutionary epochs, further re-entrant circuits appeared that linked semantic and linguistic performance to categorical and conceptualmemorysystems. This development enabled the emergence of secondary consciousness.

Ursula Voss of theUniversität Bonnbelieves that the theory ofprotoconsciousnessmay serve as adequate explanation for self-recognition found in birds, as they would develop secondary consciousness during REM sleep.She added that many types of birds have very sophisticated language systems. Don Kuiken of the University of Alberta finds such research interesting as well as if we continue to study consciousness with animal models (with differing types of consciousness), we would be able to separate the different forms of reflectiveness found in today's world.

For the advocates of the idea of a secondary consciousness,self-recognitionserves as a critical component and a key defining measure. What is most interesting then, is the evolutionary appeal that arises with the concept of self-recognition. In non-human species and in children, themirror test(see above) has been used as an indicator ofself-awareness.

Declarations on animal consciousness

Cambridge Declaration on Consciousness

Cambridge Declaration on Consciousness

The absence of aneocortexdoes 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 exhibitintentional behaviors.Consequently, the weight of evidence indicates that humans are not unique in possessing theneurological substratesthat generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.

In 2012, a group of neuroscientists attending a conference on "Consciousness in Human and non-Human Animals" at theUniversity of Cambridgein the UK, signed theCambridge Declaration on Consciousness(see box on the right).

In the accompanying text they "unequivocally" asserted:

• "The field of Consciousness research is rapidly evolving. Abundant new techniques and strategies for human and non-human animal research have been developed. Consequently, more data is becoming readily available, and this calls for a periodic reevaluation of previously held preconceptions in this field. Studies of non-human animals have shown thathomologousbrain circuitscorrelated with conscious experience and perception can be selectively facilitated and disrupted to assess whether they are in fact necessary for those experiences. Moreover, in humans, new non-invasive techniques are readily available to survey thecorrelates of consciousness."

• "Theneural substratesof emotions do not appear to be confined to cortical structures. In fact,subcorticalneural networks aroused during affective states in humans are also critically important for generating emotional behaviors in animals. Artificial arousal of the same brain regions generates corresponding behavior and feeling states in both humans and non-human animals. Wherever in the brain one evokes instinctual emotional behaviors in non-human animals, many of the ensuing behaviors are consistent with experienced feeling states, including those internal states that are rewarding and punishing. Deep brain stimulation of these systems in humans can also generate similar affective states. Systems associated with affect are concentrated in subcortical regions where neuralhomologiesabound. Young human and non-human animals without neocortices retain these brain-mind functions. Furthermore,neural circuitssupporting behavioral/electrophysiologicalstates of attentiveness, sleep and decision making appear to have arisen in evolution as early as the invertebrate radiation, being evident in insects and cephalopod mollusks (e.g., octopus). "

• "Birds appear to offer, in their behavior, neurophysiology, and neuroanatomy a striking case ofparallel evolutionof consciousness. Evidence of near human-like levels of consciousness has been most dramatically observed ingrey parrots.Mammalian and avian emotional networks and cognitive microcircuitries appear to be far more homologous than previously thought. Moreover, certain species of birds have been found to exhibit neuralsleep patternssimilar to those of mammals, including REM sleep and, as was demonstrated inzebra finches,neurophysiological patterns previously thought to require a mammalian neocortex.Magpiesin particular have been shown to exhibit striking similarities to humans, great apes, dolphins, and elephants in studies ofmirror self-recognition."

• "In humans, the effect of certainhallucinogensappears to be associated with a disruption in cortical feedforward and feedback processing. Pharmacological interventions in non-human animals with compounds known to affect conscious behavior in humans can lead to similar perturbations in behavior in non-human animals. In humans, there is evidence to suggest that awareness is correlated with cortical activity, which does not exclude possible contributions by subcortical or early cortical processing, as in visual awareness. Evidence that human and non-human animal emotional feelings arise from homologous subcortical brain networks provide compelling evidence for evolutionarily shared primal affective qualia. "

New York Declaration on Animal Consciousness

In 2024, a conference on "The Emerging Science of Animal Consciousness" atNew York UniversityproducedThe New York Declaration on Animal Consciousness.This brief declaration, signed by a number of academics, asserts that, as well as "strong scientific support for attributions of conscious experience to other mammals and to birds", there is additional empirical evidence which "indicates at least a realistic possibility of conscious experience in all vertebrates (including reptiles, amphibians, and fishes) and many invertebrates (including, at minimum, cephalopod mollusks, decapod crustaceans, and insects)."The declaration further asserts that "when there is a realistic possibility of conscious experience in an animal, it is irresponsible to ignore that possibility in decisions affecting that animal".

Examples

Theories of brain evolution in animals. The old scala naturae model versus the modern approach.

A common image is thescala naturae,the ladder of nature on which animals of different species occupy successively higher rungs, with humans typically at the top.A more useful approach has been to recognize that different animals may have different kinds of cognitive processes, which are better understood in terms of the ways in which they are cognitively adapted to their different ecological niches, than by positing any kind of hierarchy.

Mammals

See also:Elephant cognition,Primate cognition,andCetacean intelligence § Self-awareness

Dogs

See also:Dog intelligence

Dogs were previously listed as non-self-aware animals. Traditionally, self-consciousness was evaluated via themirror test.But dogs, and many other animals, are not (as) visually oriented.A 2015 study claims that the "sniff test of self-recognition" (STSR) provides significant evidence of self-awareness in dogs, and could play a crucial role in showing that this capacity is not a specific feature of only great apes, humans and a few other animals, but it depends on the way in which researchers try to verify it. According to the biologist Roberto Cazzolla Gatti (who published the study), "the innovative approach to test the self-awareness with a smell test highlights the need to shift the paradigm of the anthropocentric idea of consciousness to a species-specific perspective".This study has been confirmed by another study.

Birds

See also:Bird intelligence

Grey parrots

Research with captivegrey parrots,especiallyIrene Pepperberg's work with an individual namedAlex,has demonstrated they possess the ability to associate simple human words with meanings, and to intelligently apply the abstract concepts of shape, colour, number, zero-sense, etc. According to Pepperberg and other scientists, they perform many cognitive tasks at the level of dolphins, chimpanzees, and even humantoddlers.Another notable African grey isN'kisi,which in 2004 was said to have a vocabulary of over 950 words which she used in creative ways.For example, whenJane Goodallvisited N'kisi in his New York home, he greeted her with "Got a chimp?" because he had seen pictures of her with chimpanzees in Africa.

In 2011, research led by Dalila Bovet ofParis West University Nanterre La Défense,demonstrated grey parrots were able to coordinate and collaborate with each other to an extent. They were able to solve problems such as two birds having to pull strings at the same time to obtain food. In another example, one bird stood on a perch to release a food-laden tray, while the other pulled the tray out from the test apparatus. Both would then feed. The birds were observed waiting for their partners to perform the necessary actions so their behaviour could be synchronized. The parrots appeared to express individual preferences as to which of the other test birds they would work with.

Corvids

TheEurasian magpiepasses themirror test.

It was thought that self-recognition was restricted to mammals with large brains and highly evolved social cognition, but absent from animals without aneocortex.However, in 2008, an investigation of self-recognition incorvidswas conducted to determine the ability of self-recognition in the magpie. Mammals and birds inherited the same brain components from their last commonancestornearly 300 million years ago, and have since independently evolved and formed significantly different brain types. The results of the mirror test showed that althoughmagpiesdo not have a neocortex, they are capable of understanding that a mirror image belongs to their own body. The findings show that magpies respond to the mirror test in a manner similar to that of apes, dolphins, killer whales, pigs and elephants.

A 2020 study found thatcarrion crowsshow a neuronal response that correlates with theirperceptionof a stimulus, which they argue to be an empirical marker of (avian) sensory consciousness – the conscious perception of sensory input – in the crows which do not have acerebral cortex.The study thereby substantiates the theory that conscious perception does not require a cerebral cortex and that the basic foundations for it – and possibly for human-type consciousness – may have evolved before the last common ancestor >320 Mya or independently in birds.A related study showed that the birds'pallium's neuroarchitecture is reminiscent of the mammalian cortex.

Invertebrates

Octopustravelling with shells collected for protection

See also:Cephalopod intelligenceandPain in invertebrates

Octopusesare highly intelligent, possibly more so than any other order ofinvertebrates.The level of their intelligence and learning capability are debated,but maze andproblem-solvingstudies show they have bothshort-andlong-term memory.Octopus have a highly complexnervous system,only part of which is localized in theirbrain.Two-thirds of an octopus'sneuronsare found in the nerve cords of their arms. Octopus arms show a variety of complexreflexactions that persist even when they have no input from the brain.Unlike vertebrates, the complex motor skills of octopuses are not organized in their brain using an internalsomatotopic mapof their body, instead using a non-somatotopic system unique to large-brained invertebrates.Some octopuses, such as themimic octopus,move their arms in ways that emulate the shape and movements of othersea creatures.

In laboratory studies, octopuses can easily be trained to distinguish between different shapes and patterns. They reportedly useobservational learning,although the validity of these findings is contested.Octopuses have also been observed toplay:repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.Octopuses often escape from their aquarium and sometimes enter others. They have boardedfishing boatsand opened holds to eat crabs.At least four specimens of the veined octopus (Amphioctopus marginatus) have been witnessed retrieving discardedcoconutshells, manipulating them, and then reassembling them to use as shelter.

Shamanistic and religious views

Shamanisticand other traditional cultures and folk tales speak of animal spirits and the consciousness of animals.In India,Jainsconsider all thejivas(living organisms, including plants, animals and insects) to be conscious.

Researchers

See also the categoriesEthologistsandConsciousness researchers and theorists

Some contributors to relevant research on animal consciousness include:

• Marc Bekoff
• Peter Carruthers
• Antonio Damasio
• Marian Stamp Dawkins
• Frans de Waal
• Shaun Gallagher
• Gordon G. Gallup
• Donald Griffin
• Nicholas Humphrey
• Christof Koch
• Thomas Nagel
• Irene Pepperberg
• Bernard Rollin
• Jeffrey M. Schwartz
• Jakob von Uexküll

See also

• Animal cognition
• Animal communication
• Animal rights
• Animal rights by country or territory
• Artificial consciousness
• Awareness
• Biosemiotics
• Brain in a vat
• Cognitive ethology
• Consciousness
• Descartes' Error
• Emotion in animals
• Epiphenomenalism
• Explanatory gap
• Ethics of uncertain sentience
• Externalism
• Hard problem of consciousness
• Human–animal communication
• Internalism and externalism
• Meat paradox
• Mind–body problem
• Neural correlates of consciousness
• Philosophy of mind
• Plant perception (paranormal)
• Problem of other minds
• Self-awareness in animals
• Sentience
• Sentient beings (Buddhism)
• Spindle neuron
• Veganism
• Zoosemiotics

Further reading

• Bayn T, Cleeremans A and Wilken P (2009)The Oxford companion to consciousnesspp. 43f, Oxford University Press.ISBN978-0-19-856951-0.
• Bekoff, Marc(2013)Why Dogs Hump and Bees Get DepressedNew World Library.ISBN978-1-60868-220-1.
• Bekoff, Marc;Jane Goodall(2007).The Emotional Lives of Animals.New World Library.ISBN978-1-57731-502-5.
• Bekoff, Marc (2003)."Consciousness and Self in Animals: Some Reflections"(PDF).Zygon.38(2): 229–245.doi:10.1111/1467-9744.00497.
• Brown, Jason W (2010)Neuropsychological Foundations of Conscious Experiencepp. 200–210, Les Editions Chromatika.ISBN978-2-930517-07-0.
• Cartmill, Matt (December 2000). "Animal Consciousness: Some Philosophical, Methodological, and Evolutionary Problems1".American Zoologist.40(6): 835–846.doi:10.1668/0003-1569(2000)040[0835:acspma]2.0.co;2.
• Dawkins, Marian Stamp(2012)Why animals matter: Animal consciousness, animal welfare, and human well-beingOxford University Press.ISBN978-0-19-958782-7.
• Dawkins, Marian Stamp (1998)Through our eyes only? The search for animal consciousnessOxford University Press.ISBN978-0-19-850320-0.
• Dol, Marcel (1997)Animal consciousness and animal ethics: perspectives from the NetherlandsUitgeverij Van Gorcum.ISBN978-90-232-3215-5.
• Griffin, Donald Redfield (1976)The Question of Animal AwarenessRockefeller Univ. Press.
• Griffin, Donald Redfield (2001)Animal minds: beyond cognition to consciousnessUniversity of Chicago Press.ISBN978-0-226-30865-4.
• Huxley, TH (1874)."On the hypothesis that animals are automata, and its history"(PDF).Nature.10(253): 362–366.Bibcode:1874Natur..10..362..doi:10.1038/010362a0.S2CID4113131.
• Kunkel HO (2000)Human issues in animal agriculturepp. 213–214. Texas A&M University Press.ISBN978-0-89096-927-4.
• Lurz, Robert"Animal Minds"Internet Encyclopedia of Philosophy.
• Phillips, Clive (2009)The Welfare of Animals: The Silent MajoritySpringer.ISBN978-1-4020-9218-3.
• Reznikova, Zh. I. (2007)Animal Intelligence: From Individual to Social Cognition.Cambridge University Press
• Samorini, Giorgio(2002)Animals and Psychedelics: The Natural World and the Instinct to Alter ConsciousnessInner Traditions/Bear.ISBN978-0-89281-986-7.Review
• Schönfeld, Martin (2006). "Animal Consciousness: Paradigm Change in the Life Sciences".Perspectives on Science.14(3): 354–381.doi:10.1162/posc.2006.14.3.354.S2CID145128785.
• Shettleworth, S. J. (1998) (2010,2nd ed)Cognition, evolution and behavior.New York: Oxford University Press.
• Smith, J. D., Beran, M. J., Couchman, J. J., Coutinho, M. V. C., & Boomer, J. B. (2009).Animal metacognition: Problems and prospects,[1]Comparative Cognition and Behavior Reviews, 4, 40–53.
• Steiner, Gary (2008)Animals and the moral community: mental life, moral status, and kinshippp. 11–12, Columbia University Press.ISBN978-0-231-14234-2.
• Stenholm, Stig(2011)The Quest for Reality: Bohr and Wittgenstein: Two Complementary Viewspp. 88–92, Oxford University Press.ISBN978-0-19-960358-9.
• Van Riel, Gerd (2009)Ancient perspectives on Aristotle's De animaLeuven University Press.ISBN978-90-5867-772-3.
• Walker, Stephen (1983)Animal thoughtp. 98, Routledge.ISBN978-0-7100-9037-9.

Invertebrates

• Smith, J. A. (1991). "A Question of Pain in Invertebrates".ILAR Journal.33(1–2): 25–31.doi:10.1093/ilar.33.1-2.25.
• Sømme, Lauritz S. (2005)"Sentience and pain in invertebrates"Report to Norwegian Scientific Committee for Food Safety.
• Consciousness in a CockroachDiscover,10 January 2007.
• Do insects Feel pain?

External links

• Animal consciousnessat theStanford Encyclopedia of Philosophy
• Bekoff, Marc2012Animals are conscious and should be treated as suchNew Scientist,24 September 2012.
• Koch, Christof,"Consciousness Is Everywhere",Huffington Post,15 August 2012.
• "Octopuses Gain Consciousness (According to Scientists' Declaration)",by Katherine Harmon Courage,Scientific American,21 August 2012.
• ""The absence of a neocortex does not appear to preclude an organism from experiencing affective states""by Richard Marsden, The Business of Emotions, 4 September 2012.
• Animals are as with it as humans, scientists say,Discovery News,24 August 2012, by George Dvorsky, io9.
• "Human exceptionalism is for the birds"by Michael Cook, 7 September 2012, BioEdge
• How do octopuses think?ABCinterview withPeter Godfrey-Smith.
• Do animals demonstrate consciousness?HowStuffWorks.Accessed 30 January 2012.
• I, cockroachArchived14 July 2014 at theWayback MachineAeon,19 November 2013.
• One of UsEssay byJohn Jeremiah SullivaninLapham's Quarterly,25 March 2014.
• Elephants mourn. Dogs love. Why do we deny the feelings of other species?The Guardian.11 October 2017.