Since
Descartes's proposal of
dualism, it became general consensus that the mind had become a matter of
philosophy and 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 Damasio and
Gerald Edelman are 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 terms
primary consciousness and
secondary consciousness.
Eugene Linden, author of ''The Parrot's Lament'' suggests 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. Philosopher
Daniel Dennett counters: Consciousness in mammals (including humans) is an aspect of the mind generally thought to comprise qualities such as
subjectivity,
sentience, and the ability to
perceive the relationship between
oneself and one's
environment. It is a subject of much research in
philosophy of mind,
psychology,
neuroscience, and
cognitive science. Some philosophers divide consciousness into
phenomenal consciousness, 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 as
qualia. Phenomenal consciousness is usually consciousness
of something or
about something, a property known as
intentionality in philosophy of mind. In a new study conducted in
rhesus 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 The sense in which animals (or human infants) can be said to have
consciousness or a
self-concept has been hotly debated; it is often referred to as the debate over animal minds. The best known research technique in this area is the
mirror test devised by
Gordon G. Gallup, in which the skin of an animal (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,
orangutans and
gorillas) and
elephants. • Cetaceans:
bottlenose dolphins,
killer whales and possibly
false killer whales. • Birds:
magpies and
pigeons (can pass the mirror test after training in the prerequisite behaviors). Until recently, it was thought that self-recognition was absent in animals without a
neocortex, and was restricted to mammals with large brains and well-developed social cognition. However, in 2008, a study of self-recognition in
corvids reported significant results for magpies. Mammals and birds inherited the same brain components from their last common
ancestor nearly 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-less
magpies are 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 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 wrasses have 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 responded 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 the
olfactory sense in dogs. A study in 2015 showed that the "sniff test of self-recognition (STSR)" provides evidence of
self-awareness in dogs.
Pain or suffering Further arguments revolve around the ability of animals to feel
pain or
suffering, which implies consciousness. If animals can be shown to suffer in ways comparable to humans, ethical arguments against human suffering may be extended to animals. Some scholars argue that pain can be inferred from non-purposeful or maladaptive reactions to negative stimuli. One such reaction is
transmarginal inhibition, a phenomenon observed in both humans and some animals that resembles mental breakdown. Cosmologist
Carl Sagan argues that humans often deny animal suffering to justify practices such as enslavement, experimentation, and consumption. He contends that behavioral similarities between humans and other animals challenge such denials.
John Webster, professor of animal husbandry, argues that suffering is not dependent on intelligence or brain size. He states that sentient animals actively seek pleasure and display behaviors indicating enjoyment, such as basking in the sun. However, there is no consensus about which organisms are capable of experiencing pain. Philosopher
Justin Leiber discusses varying views:
Michel de Montaigne attributes consciousness to insects and even plants, while
Peter Singer and
Samuel Clarke deny it in simpler organisms like sponges. Singer places the boundary somewhere between shrimp and oysters, while others speculate about insects, spiders, or tapeworms. Some critics draw comparisons to plants, questioning whether a focus on animal suffering is entirely distinct. Science writer Carol Kaesuk Yoon describes how plants, when damaged, initiate chemical defenses and repair processes, though these do not necessarily imply consciousness.
Cognitive bias and emotion 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. For example, the common practice of calling
brain circuits that 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 (1899) of
neurons in the pigeon cerebellum
Neuroscience is the scientific study of the
nervous system. It is a highly active
interdisciplinary science that collaborates with many other fields. The scope of neuroscience has broadened recently to include
molecular,
cellular,
developmental,
structural,
functional,
evolutionary,
computational, and
medical aspects of the nervous system. Theoretical studies of
neural networks are being complemented with techniques for
imaging sensory and motor tasks in the
brain. 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. Neuroscientists use empirical approaches to discover
neural correlates of subjective phenomena. The set should be
minimal because, 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 by
Francis Crick and
Christof Koch. They concluded
sensory neuroscience can 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 es needed a mammalian
neocortex. Recently that view has been challenged, and many researchers now believe that animal consciousness can arise from
homologous subcortical brain networks.
Attention Attention is the
cognitive process of 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 one
neural correlate of 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 the
EEG. Many animals, including humans, produce
gamma waves (40–60 Hz) when focusing attention on a particular object or activity.
Extended consciousness Extended consciousness is 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 by
Antonio Damasio and is used in
biological psychology. Extended consciousness is said to arise in structures in the
human brain described as
image spaces and
dispositional spaces. Image spaces imply areas where
sensory impressions of all types are processed, including the focused awareness of the
core 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 Metacognition is defined as "
cognition about 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. 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 as
De Anima and the
Parva Naturalia of the Greek philosopher
Aristotle. Metacognologists believe that the ability to consciously think about thinking is unique to
sapient species and indeed is one of the definitions of sapience. There is evidence that
rhesus monkeys and 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 in
rats, but further analysis suggested that they may have been following simple
operant conditioning principles, or a behavioral economic model.
Mirror neurons Mirror neurons are
neurons that
fire both 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 in
primate and other species including
birds. 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 the
common coding theory). while others relate mirror neurons to
language abilities. 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 as
empathy.
Vilayanur S. Ramachandran has speculated that mirror neurons may provide the neurological basis of self-awareness.
Evolutionary psychology Consciousness is likely an evolved
adaptation since it meets
George Williams' criteria of species universality, complexity, and functionality, and it is a
trait that apparently increases
fitness. Opinions are divided as to where in biological
evolution consciousness emerged and about whether or not consciousness has survival value. It has been argued that consciousness emerged (i) exclusively with the first
humans, (ii) exclusively with the first mammals, (iii) independently in mammals and birds, or (iv) with the first reptiles.
Donald Griffin suggests in his book
Animal Minds a 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 Eccles argues that special anatomical and physical adaptations of the mammalian
cerebral cortex gave 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 social
and natural 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 by
Bernard J. Baars.
Richard Dawkins suggested 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. 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 an
awareness of 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 various
subjective sensory contents of consciousness such as
sensations,
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 own
consciousness. The ability allows its possessors to go beyond the limits of the remembered present of
primary consciousness. Primary consciousness can be defined as simple awareness that includes
perception and
emotion. As such, it is ascribed to most animals. By contrast, secondary consciousness depends on and includes such features as self-reflective awareness,
abstract thinking,
volition and
metacognition. Edelman's theory focuses on two
nervous system organizations: the
brainstem and
limbic systems on one side and the
thalamus and
cerebral cortex on 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 learn
adaptive behaviors. These scientists also point out that the cortex might not be as important to primary consciousness as some neuroscientists have believed. Ursula Voss of the
Universität Bonn believes that the theory of
protoconsciousness may 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-recognition serves 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, the
mirror test (see above) has been used as an indicator of
self-awareness.
Multidimensional framework A 2020 paper by
Jonathan Birch, Alexandra K. Schnell, and Nicola S. Clayton outlined a multidimensional approach to animal consciousness, intended to account for variation in conscious experience across species. The authors propose that consciousness may not be meaningfully represented along a single continuum, and instead suggest five distinct dimensions for constructing species-specific profiles. The proposed dimensions are: •
Perceptual richness (p-richness): the level of sensory detail present in conscious perception, which may vary across different sensory modalities such as vision, olfaction, or touch. •
Evaluative richness (e-richness): the complexity of affective states, including positive and negative valence, and their role in guiding behaviour. •
Unity: the degree to which conscious experience is integrated into a single perspective at a given moment. •
Temporality: the integration of experience over time, including continuity, memory, and anticipation of future events. •
Selfhood: the extent to which an animal exhibits self-related processing, from distinguishing between self and environment to more complex capacities such as mirror self-recognition. The authors suggest that this framework could facilitate comparative studies of consciousness in different taxa, including mammals, birds, and cephalopods. ==Declarations==