by Paul Singh
Without some scientific understanding of what the brain is capable of doing, imaginative notions can run wild, unrestrained by facts. Consciousness is one of those notions. There are as many unscientific definitions of consciousness as there are philosophers, theologians, and religious gurus. That forbids any clear definition of consciousness. But science needn’t be deterred by the vagueness of terms at the beginning of inquiries. Scientific progress controls the refinement and replacement of terms used in theories.
There cannot be any doubt that nervous systems are involved with consciousness. Brains, for example, obviously exist, and it is equally obvious that they allow us to be conscious. Exploring how brains do this involves several sciences, such as biology, neurology, neuroscience, and cognitive psychology. How animals and human beings can be conscious is one of the most important questions that science can explore. Consciousness, on the other hand, isn’t. That’s because consciousness doesn’t have its own separate existence.
Brains obviously allow animals to enjoy conscious engagements with their world, but it is those brains and those engagements that exist, not some additional consciousness that must be added to the brain. There is no independent entity called consciousness. There is only what brains are doing in the world. Consciousness is an emergent manifestation of the brain, is non-physical in nature, unable to do anything on its own, and is totally ineffective without the brain, so it can be considered to be an illusion at best.
Consider the following facts:
• Every person that has consciousness has a brain.
• The brain is thoroughly connected with the surface of the body and the entire interior of the body.
• Consciousness is extremely complex, and so is the brain which has about 100 billion interconnected neurons.
• Dramatic changes to consciousness easily happen because of some kind of alteration to the brain, such as an injury, the ingestion of chemicals, or a brain disease.
• Nothing eliminates consciousness as effectively as disconnecting or destroying the brain.
• Unless consciousness has no relationship with any part of the body (which is very unlikely), then the bodily organ that consciousness has the closest relationship with must be the brain.
Rare is the neuroscientific research paper that discusses consciousness without actually describing brain processes that can be empirically investigated. Consider how there are no longer any medical research papers talking just about disease from beginning to end. Medical researchers instead describe such things as viral infections, cancerous lesions, chronic arthritis, and so forth, without presuming that they all actually have something in common. Similarly, there is probably very little in common shared by all the things that have ever been considered as an aspect or kind of consciousness. The term “consciousness” wasn’t anything close to a scientific term when it entered the European lexicon many centuries ago. Indeed, it may never acquire a scientific status.1
Philosophy hasn’t been any help in understanding the nature of consciousness. Never agreeing, philosophers usually resort to conventional meanings, vague metaphor, poetic license, or shameless appeals to their readers, who surely must be enjoying consciousness already, so no definition is needed! Being conscious of what one is reading is always helpful for comprehension, no doubt. But that’s just a roundabout way of saying that one sees what one is reading. How does consciousness get involved?
To be conscious, however, has some clear meanings. If one is not conscious of something, then one is unaware of it, doesn’t take it into account, and has no thoughts about it. There are tests for being conscious, such as testing for a response to a sensory stimulus. No reaction or response at all suggests a lack of awareness. Being conscious can have many levels, as medicine and psychology know, and the levels and types of unconscious neural processes far outnumber the conscious levels. Even at the level of conscious awareness, cognitive functioning may be extremely limited. A person who has suffered a serious brain injury may be responsive to a bright object held before the eyes, as the eyes follow its motions and a hand stretches out for it. But there may be no ability to grasp that object and properly use it to do anything. Unless one can take into account what nearby objects are and make some employment of them, there is no sentience going on.2 To be sentient, an animal must be able to make practical use of things around it. Eating food, building nests, and finding mates are examples. Insects and reptiles are aware and sentient in this minimal sense, and so are birds and mammals.
People are normally quite sentient, and our powers of intelligence also permit thoughtful sentience. We can not only put things around us to immediate use, but we can also recognize the meanings and values of things permitting their use at some other time, and we can even think about how to use them differently for other purposes if necessary. Where there are thoughts, things acquire significance and expanded meaning. What we call a “thought” about something is just an appreciation for the expanding significances, the longer-range implications of it. A stick has very little “potential” for an insect, and only a little more for a typical mammal. Humans are not typical mammals. When I pick up a long stick, I am not only aware of it, as an ant crawling along it can be. I can also sentiently grab that stick to chase away a sudden threat. I can even imagine how it could be a tool if it was thoughtfully shaped and sharpened.
Being conscious, for us humans, usually involves all three levels: awareness, sentience, and thoughtfulness. Babies have sensory awareness and a little sentience, so they are surely conscious beings before they develop higher cognitive capacities. What developmental psychologists often call ‘metacognition,” the ability that grows during infancy to figure out what other people are intending and thinking, is a fascinating process to study.3 Birds can’t develop those abilities. A typical bird has sensory awareness and a little sentience as well, but nothing more. The awareness and sentience of a bird isn’t similar in quality to a baby’s, but the same ingredients are basically present for enjoying conscious awareness. From a strictly biological standpoint, there is no reason to say that the bird is not conscious at all. It passes the same tests we apply to animals and ourselves—responsive awareness to matters around it, and the ability to use certain things in its environment to get what it wants. Birds even use signaling and singing as rudimentary communications.
The objection is promptly raised, “But those birds aren’t intentionally trying to talk to each other, and it’s all a matter of instinct since they don’t realize what they are doing.” No, birds aren’t communicating with a concept-rich language like ours, and they aren’t self-consciously contemplating what they are doing. But those inabilities are about the lack of thoughtfulness, not the lack of sensory awareness or sentience. No, birds aren’t thinking about how to signal each other, and they aren’t able to think about changing the signaling system so it can have additional uses. It’s just instinctive, we would say. All the same, what birds do with their awareness is a separate question from whether sensory awareness is present. Sensory awareness in birds only triggers inflexible habits, such as signaling instincts, but it is probably a kind of conscious awareness all the same.
All animal nervous systems process most sensory stimulations unconsciously, without doubt. But to suppose that there is a hard line dividing human brains from all other animal nervous systems, so that only humanity enjoys both conscious and unconscious sentience, is to engage in unscientific magical thinking. It’s all too easy, and unscientific, to presumptively dismiss “lower” animal perception as entirely unconscious. Birds clearly do not have the complex nervous structures that we have, yet they do utilize simpler counterparts to our brain’s main components. Consciousness is a continuum from the simplest to the most complex animals.
Some species of parrots are remarkable for their intelligence and a degree of self-awareness once thought to be uniquely human. Neurobiologist R. Glenn Northcutt, at the Scripps Institution of Oceanography and Department of Neuroscie
nces of the University of California, San Diego, has declared that “there is little question that Great Apes and African Parrots have a sense of self and personal experience over time.”4 The scientific investigation into the way brains of all sorts generate awareness, sentience, and thoughtfulness is producing remarkable results that are forever changing what we think about what consciousness is.
The Conscious Brain
The neuroscientist V. S. Ramachandran is clear about crediting the brain’s complexities for generating what goes on in conscious experience. Neurons are connected into networks that can process information. The brain's many dozens of structures are ultimately all purpose-built networks of neurons, and often have elegant internal organization. Each of these structures performs some set of discrete (though not always easy to decipher) cognitive or physiological functions. Each structure makes patterned connections with other brain structures, thus forming circuits. Circuits pass information back and forth and in repeating loops, and allow brain structures to work together to create sophisticated perceptions, thoughts, and behaviors.5
Another neuroscientist who has deeply pondered mind-brain connections is William Uttal. He can’t emphasize strongly enough how complex the brain is at every level down to the individual neuron, more than complex enough to sustain such an impressive process as conscious life. However, Uttal notes that complexity slows down the pace of scientific learning about the brain:
Unfortunately, the presumed level of brain activity (the interactions among a vast number of neurons) at which we believe the salient information processes are carried out that become sentience, consciousness, and mental activities of all kinds is exactly the level at which our research techniques are least adequate; the most fundamental reason, as noted, being the extraordinary complexity and number of the neurons involved and the idiosyncratic nature of every neuron-to-neuron interaction.6
All the same, we cannot simply give up trying to understand the brain because of its enormous complexity. Many aspects of the brain’s functioning have become well understood. Both the successes and limitations of the brain sciences must be acknowledged by anyone seeking an explanation for consciousness.
The brain stem—the medulla oblongata and pons—and the thalamus and hypothalamus, both of which are located at the top of the brain stem, are required for wakeful awareness and sensory alertness, and they are needed for core emotional moods (energetic, lethargic, sad, fearful, etc.) and drives (for food, safety, sex, etc.) which permit purposeful sentient activity. These deepest parts of the brain allow an external sense of contact with surroundings, an internal sense of feeling one’s own body and its dimensions and positioning, the feeling of internal states of comfort or discomfort, and feeling basic moods and emotions. Every animal more complex than worms, insects, clams, crustaceans, and octopods uses these basic brain components.
Additional deep brain structures in the limbic system—such as the amygdala, cingulate gyrus, and hippocampus—contribute emotional regulation and episodic memory so that experiences coming in from the external senses and processed by cortical areas can have significance and familiar events can be recognized. The brain stem and the limbic system supply what may be called “core” awareness. This core of minimal sensitivity to how one’s body is feeling internally and responding to sensed things nearby is more complex than simply reacting automatically to sensations. Core conscious awareness permits the beginnings of sentience: the ability to react differently to different stimuli depending on one’s own bodily condition. This is the beginning of purposive behavior, and conscious awareness is probably the inner manifestation of that neurological functioning. If there are no sensed options, then there can be no selected purposes, and hence no conscious awareness.7
After the brain stem and the limbic system, the cerebellum is the oldest part of animal brains, and is possessed by all vertebrates. The cerebellum contributes fine motor control for precise movements, but it isn’t responsible for conscious awareness.
Between the limbic system and the much larger cerebral cortex, several intermediary structures connect the limbic system with many cortical systems. The components of the basal ganglia, such as the striatum, along with the claustrum, serve as broad highways for fast-moving communication traffic to coordinate sensory, cognitive, and motor functions. These parts of the brain, which are only understood to a limited extent, apparently serve hugely important functions, which are far greater than one might expect from their small size. All mammals have these inner brain structures, indicating that they grew in importance as the mammalian outer cortex emerged with its characteristically larger and more complex features. Intelligence requires the processing of more information, but extra information by itself doesn’t guarantee smarter behavior—instead, distraction and interruption may result. Additional neural complexity requires additional neural coordination because the attentive behavior of the more intelligent mammal still has to be rapidly and smoothly effective rather than hesitant or spastic.
The striatum has received heightened scrutiny from neuroscientists trying to explain the rapid learning abilities displayed by mammals. Fast learning under all sorts of circumstances requires the most intricate interconnections among intellectual calculations, fine motor control over many muscles, and instant judgments about success or failure. Mammals have extra cortical capacities for this reason, but the cortex isn’t enough. The prefrontal cortex is essential for smart adaptive behaviors, because it suggests what should be done based on estimates of predictable outcomes. However, trial experiments are pointless without error detection and correction. Learning requires feedback loops that inform the prefrontal cortex about how well planned behaviors are working, so adjustments can be attempted for better success in the future. Those feedback loops have been discovered in the striatum, which is heavily interconnected between the prefrontal cortex and the limbic system.8 As for the claustrum, it attracted the notice of scientists Francis Crick and Christof Koch. They suggested that the claustrum is responsible for coordinating so much vital inter-cortical information that it effectively ensures a smooth harmony and consistency to conscious experience. Although the claustrum remains fairly mysterious, the idea that some specialized segments of the deep brain are responsible for harmonizing and coordinating information makes good sense.9
Those features of harmony and consistency prevalent in conscious attention mustn’t be exaggerated. One’s attention span isn’t very long under ideal circumstances, and higher cognitive centers are especially able to revise episodically the attention’s grasp on what is going on minute by minute. Still, conscious attention usually has more continuity than discontinuity, and there are smooth transitions between episodic shifts. We notice if abrupt gaps or odd breaks separate episodes of experiences, just as we can feel that something is amiss when we view a badly edited video or movie. There are transitions to experience, but we expect long stretches of experiences (as much as a few minutes) to feel like a coherent whole rather than a series of disconnected and unrelated parts. The American psychologist and philosopher William James was among the first to highlight these features of experience, labeling the phenomenon “stream of consciousness.”10 Similarly, a contemporary philosopher who is equally at home with psychology, Daniel Dennett, had to emphasize how experience isn’t so unified or coherent as it might appear when we aren’t reflecting on it.11
Most of the mammalian brain consists of the cerebral cortex for sophisticated cognition. The cortex has four areas, or lobes. They are the frontal lobe, the parietal lobe, the temporal lobe, and the occipital lobe. The occipital lobe found in mammals is responsible for handling visual information and perceptual discrimination. Damage to this area can cause disorientation or blindness, but not necessarily loss of consciousness. The orbitofrontal cortex, in the frontal lobe, is one of the oldest regions of the vertebrate brain, emerging with the rise of mammals around 175 million years ago. The orbitofrontal cortex permits faster learning and behavior control by comparing ex
pectations with outcomes, confirming rewards, and exercising drive inhibition—all necessary abilities for mammals exploring complicated environments and managing lasting relationships with kin.
The rest of the prefrontal cortex, the foremost part of the frontal lobe, adds sophisticated abilities to focus on one’s own conduct, think before one’s acts, plan out behavior in advance, make complex decisions, solve problems, and consider the social consequences of one’s actions. These abilities together comprise what psychologists call “executive function.” Infants have to slowly acquire basic executive functioning. Young childhood is a time for learning how to control oneself, take responsibility, be cooperative, and be considerate of others. The essentials for acquiring a sense of self (who one is, what one thinks) arise along with an understanding that others have their own selves too. The period of adolescence is marked by a heightened sense of self and self-abilities, and the development of meta-cognition, that is, careful reflection about one’s own thoughts and behaviors.12
The frontal lobe couldn’t do its work of controlling conduct into the future without extensively consulting with other areas of the brain responsible for monitoring the environment, communicating with others in one’s species, and maintaining long-term memories.13
The parietal lobe contains regions that make special discriminations and form complex meanings from one’s observations, so that ongoing events get special attention and refined responses. Language is accomplished here, for example. Mirror neurons, first discovered by neurophysiologist Giacomo Rizzolatti in the 1980s, have been found in the inferior frontal and inferior parietal lobes. A mirror neuron is a neuron that fires when an animal observes the same action performed by another. Thus mirror neurons mirror the behavior of others. They are a great discovery of the last two decades. They have been widely discussed and their existence has been and confirmed. They are found in monkeys, birds, and now in humans. They mediate understanding of the other animal’s behavior. The mirror neural system is involved in empathy. The anterior insula, anterior cingulated cortex, and inferior frontal cortex are active when people experience emotion (disgust, happiness, pain) upon seeing another person. Recently Ramachandran has speculated that mirror neurons may provide the neurological basis for human self-awareness. He believes that these neurons not only can simulate other people’s behavior but also can turn inward to create secondary representations or meta-representations of our earlier brain processes, which provide a neural basis for introspection and for the reciprocity of self-awareness and other-awarenesses.
