Funding for this site is provided by readers like you.
The emergence of consciousness
The Sense of Self

Help Lien : Seeing Red. A Study in Consciousness. By Nicholas Humphrey Lien : Minding the Brain Lien : Noam Chomsky + Robert Trivers The anti-war activist and MIT linguist meets the Rutgers evolutionary biologist in the Seed Salon to discuss deceit
Lien : ROBERT TRIVERS: An Edge Special Event Lien : L'évolution et la fonction de la tromperie Lien : Sexe, mensonges et politique
Original modules
Tool Module: Primatology Primatology
  History Module: Hominization, or The History of the Human Lineage   Hominization, or The History of the Human Lineage
Tool Module: Darwin's Natural Selection   Darwin's Natural Selection

Some authors have tried to draw connections between the possible social origins of consciousness and the neurobiological models of consciousness that are currently being debated. Bruce Charlton, for example, sees Antonio Damasio’s concept of somatic markers as a highly likely candidate for the mechanism underlying all human social intelligence. According to Charlton, these somatic markers may have evolved to let us model our social relations and provide the positive or negative connotations that we needed to develop a theory of mind about other individuals.

Lien : Review of The Feeling of What Happens: Body, Emotion and the Making of Consciousness

In contrast to Nicholas Humphrey, authors such as Horace Barlow believe that introspection simply is not a sufficiently precise phenomenon to have enabled the evolution of consciousness. He agrees that consciousness has a social origin, but he suggests that it comes from communication with other people, rather than from introspection.

The question whether human beings are born with certain moral abilities that are universal and independent of cultures has been debated for centuries. But modern brain-imaging technology has now shown that there are in fact certain areas of the human brain that are specifically involved in moral decisionmaking, and that these areas are located in brain structures associated with the emotions, in particular the posterior cingulate cortex, the medial frontal gyrus, and the superior temporal sulcus.

Another interesting fact: Antonio Damasio, Michael Koenigs, Marc Hauser, and their colleagues have shown that people who had lesions in the ventromedial prefrontal cortex and who displayed weaker emotional sensitivity in their daily lives also seemed to experience less aversion to the suffering of others when they were presented with dilemmas or difficult moral choices in experimental settings.

Part of what makes this finding so interesting is that ever since the pioneering research of David Premack, all the evidence has suggested that an aversion for the suffering of others is present in young children even before they possess language, which argues strongly for the innate nature of a primitive form of morality. If that is indeed the case, how have these moral predispositions been selected for in our evolutionary history? Many scientists think the answer is the advantage provided by the ability to detect other people’s emotions effectively.

The term “emotional contagion” is used to refer to this phenomenon, in which the mere sight of a face with an expression of suffering makes us resonate with this emotional state and experience this unpleasant suffering ourselves. By following our natural inclination to soothe the other person’s suffering, we would thus soothe our own suffering at the same time!

Like Nicolas Humphrey, V.S. Ramachandran is a researcher who believes that consciousness of others may have been the first kind of consciousness to evolve, and he too regards human empathy as something fundamental. Ramachandran accords great importance to the role of mirror neurons in these phenomena of moral contagion that may have favoured the emergence of a “consciousness of self”.

These mirror neurons become activated not only when we make a specific gesture but also when we see someone else make this same gesture. Thus, Ramachandran believes, these neurons might be a physical substrate for the “inner eye” that lets us observe ourselves as if we were someone else.

Lien : THE NEUROLOGY OF SELF-AWARENESS Lien : Damage to the prefrontal cortex increases utilitarian moral judgements Chercheur : David Premack Chercheur : Joshua D. Greene


When did consciousness appear? This question can be applied to the evolution of species just as much as to the life of an individual. In the first case, the question amounts to, “Which animals species are endowed with some form of consciousness?” In the second, it becomes, “When, in the course of its development, does a human fetus, baby, or child become conscious?”

In this section we will discuss the first of these questions: the phylogenetic origins of consciousness. This question is closely related to the possible functions of conscious phenomena, because if consciousness does have a function, if it is good for something, then natural selection (follow the Tool Module link) might act upon this function. To the extent that this function gives conscious individuals a reproductive advantage, they would pass on to their descendants the genes involved in conscious processes.

To begin with, we can be fairly certain that consciousness is adaptive, at least when it is understood in the minimal sense of wakefulness. Without being consciously awake, no individual can feed itself, mate, protect its young, or take any other actions necessary for survival.

Next, some authors, such as Susan Greenfield, argue that the emergence of consciousness was a gradual process, keeping pace with the growth of the brain over the course of evolution and hence with the size and growing number of neuronal assemblies. But other authors, such as Nicholas Humphrey, instead believe that the emergence of consciousness occurred rapidly and was more of an “all or nothing” phenomenon. Humphrey thinks that consciousness appeared later in evolution, when our hominid ancestors first developed numerous, diverse social skills (follow the History Module link), such as imitation, deception, language, and the ability to construct a theory of mind for other individuals.

Humphrey thus belongs to the school of thinkers who believe that consciousness may have constituted an evolutionary advantage, but not all theorists agree with him on this matter . For Humphrey, consciousness is an emergent property that evolved for its social function. Like the species of great apes that are alive today, we humans have always lived in complex social groups in which knowing other individuals’ intentions can be extremely helpful for determining who ranks above us in the social hierarchy, whom we can trust, with whom we can form alliances, and so on.

In other words, according to Humphrey, those of our ancestors who were able to understand, predict, and manipulate other individuals’ behaviour had a definite adaptive advantage. They thereby became what Humphrey calls “natural psychologists”.

Some might counter that humans could very well have acquired these skills simply by observing other peoples’ behaviour and its consequences from the outside, somewhat like the behaviourists. But Humphrey thinks there was a better way to do it. He hypothesizes that individuals acquired the ability to look at themselves, to put themselves in someone else’s place and try to see how that made them feel inside. For example, in today’s terms, such individuals might say to themselves, “I can experience jealousy so as better to understand what someone else feels when they are jealous, which lets me better predict their behaviour.”And Humphrey’s hypothesis is that evolution favoured those individuals who had this ability over those who did not.

Humphrey compares this ability to a new sensory organ that would be oriented not toward the outside world but toward the individual’s inner world, the activity of the individual’s own brain. Of course, this “inner eye” would not see the brain’s functioning at the neuronal level, but would instead see a more “user-friendly” psychological version of this activity: what we call subjective conscious states. According to Humphrey’s theory, consciousness thus appears as a feedback loop whose function is to provide human beings with a sophisticated tool that lets them become good “natural psychologists”.

But we might ask, doesn’t assigning this role to an “inner eye” make Humphrey’s a dualist theory, or give rise to an infinite regression? No, responds Humphrey, who reaffirms his materialist position by reaffirming that the brain is indeed a machine made of neurons and molecules. And his theory does not give rise to an infinite regression either, he argues, because for him, consciousness is not a characteristic of the brain as a whole, but only this loop in which the output, through the mechanism of feedback, becomes the input.

There are several other theories on the evolutionary origins of consciousness that have the same overall thrust as Humphrey’s original proposal. For example, British archaeologist Steven Mithen also posits a function for consciousness in social mammals, but he takes Humphrey’s reasoning a step further. According to Mithen, Humphrey’s theory accounts only for humans’ consciousness of their social relations, whereas in fact humans can be conscious of many other things as well. In Mithen’s view, it was this broadening of the field of consciousness that was the critical factor in the creation of the conscious abilities that humans have today.

According to Mithen, the first hominids developed several specialized mental modules, largely independent of one another. In Homo habilis, and even in the Neanderthals, social intelligence might still have been isolated from the intelligence needed to manufacture tools or to interact with the natural environment. What we call consciousness was at that time in a sense the prisoner of this social intelligence and incapable of being extended by the rest of these specialized modules. Mithen thinks that these other modules therefore had only a fragile, fleeting form of consciousness, insufficient to let individuals engage in introspection about their methods of manufacturing tools or hunting, for example.

It was only as the “fluidity” among these various modules gradually increased that they may have become able to share their content and give rise to the human mind as we know it today. Mithen believes that this process may have coincided with the cultural explosion that the human species experienced some 30 000 to 60 000 years ago.

Mithen also embraces the theory that human language evolved as a substitute for mutual grooming in apes, as the size of hominid groups increased. The case that language may have had this kind of social origin is buttressed by the tendency of today’s humans to use language mainly to find out what one person said out about another, or what someone’s social status is, or whom they are sleeping with—in short, to gossip.

Adapted from S. Mithen (1996) in S. Blackmore,
Consciousness: An Introduction

But, Mithen continues, once language did develop, it became available for dealing with other subjects that were actually important for survival, such as hunting, natural phenomena, and so on. And that too would have contributed to the decompartmentalization that led to the emergence of consciousness.

In short, for Mithen, the selective advantages would thus have alternated between the modular specialization of skills and the fluidity of general intelligence, with some periods favouring one and some the other, as shown in the diagram to the left.

Another important phenomenon in social species is deception: the ability to mislead other members of the group so as to more readily secure resources for oneself. Evolutionary theorist Robert Trivers sees this phenomenon as central to our understanding of conscious phenomena. He argues that in those species where a selection for deception occurred, a parallel selection for self-deception took place as well.

Trivers points out that we all try to present ourselves so as to appear better than we actually are. But in addition, Trivers believes that because people who believe their own lies make the best liars, there may have been significant selective evolutionary pressure in favour of self-deception.

Our ability to fool ourselves would thus have evolved in parallel with our ability to fool other people. Indeed, when we believe our own lies, there is less risk that we will let someone else perceive any emotions or other signs that might contradict them. Because we have unconsciously suppressed part of reality and therefore have a biased vision of it ourselves, we find it easier to mislead other people, and this would constitute a selective advantage for social individuals such as we.

The whole scenario seems to suggest that our brains have developed a propensity to keep excessively compromising information beyond the reach of the conscious processes that govern our interactions with other individuals. But at the same time, our brains seem to have kept this information active in unconscious processes so that we do not isolate ourselves too much from reality. For Trivers, deception of others and self-deception are thus intimately linked and form a dynamic that is decisive for the origin of our conscious and unconscious processes.

While many theorists such as Humphrey, Mithen, and Trivers thus regard consciousness as a function for adapting to the social aspect of the human way of life, other theorists either express skepticism about this adaptationist tendency in evolutionary approaches or flatly reject the idea that consciousness might have any function that might have made it the target of selective processes.


Many theorists of the origins of the human mind do not tackle the eminently complex problem of consciousness head on. One example is Terrence Deacon and his theory of the co-evolution of the human brain and language, resulting in the appearance of a “symbolic species”. In Deacon’s view, the evolution of the human mind proceeded in parallel with the evolution of symbolic representations. Such authors therefore focus on explaining how this specific faculty for symbolic representation may have emerged.

Another indirect approach to the problem of consciousness can be seen in George Herbert Mead’s theory of symbolic interactionism. Mead believes that the consciousness of self that is a distinctive characteristic of human beings comes first from gestures and other non-symbolic interactions, and then from the symbolic interactions that are enabled by language. For Mead, consciousness is therefore a fundamentally social phenomenon, related to communication, and not an individual one.


Lien : The "shifting moral zeitgeist" Lien : Conscious mind and free will Lien : La révolte dionysiaque

Libet also conducted experiments in which he showed that when he applied a stimulus to his subjects, unconscious responsive activity in their brains was recorded several hundreds of milliseconds before it reached the threshold of neuronal activation needed for them to perceive the stimulus consciously. It is entirely normal for there to be a certain time lag in the response to a stimulus, among other reasons because of the time required for nerve impulses to travel through the neuronal circuits. But as Libet noted, it is quite remarkable to find that even if in reality we consciously perceive a stimulus about half a second after it is applied, this perception is subjectively pushed back in time to give us the impression that it occurred at just about the same time as the stimulus!

When you consider the results of these experiments carefully, they lead to some strange conclusions. For one thing, these results indicate that “subjective time”, meaning the time frame that we experience consciously, is slightly earlier than the “objective present”, meaning the time frame in which our physical brain processes actually occur. Another strange implication of these experiments is that we can never be conscious of the precise moment when our brain ceases to be awake, such as the moment when we fall asleep or when we die.

This is what led neurobiologist Michael Gazzaniga to say that what is a “scoop” for us is already old news for our brain. In other words, for many scientists who, like Gazzaniga, believe that the notion of the “self” and of free will can be attributed to cognitive illusion, whatever we are deciding consciously, our brain has already decided it for us a few milliseconds earlier.

As discussed in the next sidebar, numerous factors may thus play a far more important role than we imagine in the way that we conduct our daily lives. These factors include unconscious mechanisms that are rooted in our long evolutionary history, such as the need for individuals to survive, to find food, and to find partners in order to reproduce. Consciousness would then come along only after the fact, to justify the actions already decided upon by these unconscious mechanisms, by adapting our words and actions to the social and cultural context of the moment.

Lien : Conscious mind and free will Lien : YOU are in your BRAIN!

If, as the discussion in the preceding sidebar suggests, physical brain activity takes precedence over subjective consciousness—a clearly materialist position—then where does this brain activity that “decides for us” come from?

The neurobiologists who defend this position agree that any conscious perception, thought, or action is a variation of the brain activity of a particular individual responding to a particular context with the goal of keeping this individual in equilibrium with his or her environment. This very general explanation is consistent with a great many neurobiological models of consciousness. It is, for example, very close to the theory of “embodied cognition” and the concept of “enaction” advanced by Francisco Varela.

For now we thus have only a general framework to help us account for the way that our voluntary consciousness might operate. When authors such as Jean-Paul Baquiast, inspired by the work of Walter J. Freeman, attempt to sketch the broad outlines of this general framework, the result is something like the following:

“The individual who I am, completely involved in a plan, in a continuing relationship with my fellow persons and the rest of the world, constructs my decisions in real time through the behaviour of my entire body. My brain is informed of these decisions on a conscious level only after a brief lag. The will that I perceive as conscious did not decide on the behaviour in which I am engaged, but it does intervene to smooth out the various aspects of it, to modulate it, and finally, to legitimize it in relation to all of the meanings that constitute my personality at the deepest level.”


Most people naturally accept that they are responsible for their own actions. Indeed, when someone says that their behaviours are controlled by a force outside themselves, that is often the sign of some psychological disorder.

A good part of Western culture and religion is based on this idea of “individual voluntarism”. In the Judeo-Christian conception of free will, for example, individual responsibility is what enables us to make choices: I can choose to steal or not to steal, to kill or not to kill, etc. From the moment that I choose to steal or to kill, I become responsible for those actions, and I deserve the punishment that society inflicts on me, because the logic of the law is inspired by this Judeo-Christian conception of free will. Thus, at the deepest level, Western societies operate according to this belief in free will.

However, many scientists, such as Daniel Wegner and Henri Atlan, and many philosophers, such as Michel Onfray, believe that our conscious will may play a smaller role in our decision-making than we think. In fact, many of these thinkers believe that it might well be nothing but an illusion. They thus call into question our entire societal logic that is based on free will. These thinkers believe that every individual is determined by countless genetic and cultural factors with interactions that are so complex and that we are still so far from understanding that we have an exaggerated impression of our own freedom of action.

But if we therefore attempt to incorporate free will into a materialist conception of the brain and the physical laws that govern the universe, we soon see that that is no easy undertaking either, as witness the past centuries of debate that have surrounded this question. In recent decades, however, the neurosciences have helped to advance this debate by exploring the mechanisms of consciousness within the brain.

Perhaps the most hotly debated neuroscientific experiments on conscious intention and voluntary action were conducted by neurobiologist Benjamin Libet in 1983. In these experiments, the subjects were simply asked to flex their wrists at a moment of their choosing. The only other thing they had to do was keep an eye on a circular screen on which a spot of light was revolving, and remember the “clock position” of the spot at the moment they decided to flex their wrists.

During each experimental trial, the subject performed 40 of these wrist flexions while Libet and his colleagues measured three things. The first was the start of the wrist movement, measured with electrodes attached to the wrist and connected to an electromyograph (EMG). The second was the fluctuation in brain activity associated with the decision to move the wrist; this fluctuation too was measured relatively easily, by means of electrodes attached to the subject’s scalp and connected to an electroencephalograph (EEG).

The third thing measured was the moment that the subject consciously decided to make the wrist movement, and this measurement posed the greatest challenge. If the experimenters had asked the subjects to report this moment verbally, that would have created interference with the EEG recording of their motor activity. To get around this problem, Libet used an indirect method that he had tested in various earlier experiments. In those experiments, the subjects had to estimate the start of other events by remembering the position of a spot of light revolving around a circular screen. From these controlled experiments, Libet had concluded that this device was reliable enough to enable his subjects to note the precise moment when they they decided to make each wrist movement.

The results of Libet’s three sets of measurements clearly showed a characteristic brain activity called a “readiness potential” (RP) that occurred approximately 350 milliseconds (ms) before the time that the subject reported as when he made the conscious decision (CD) to flex his wrist. Then, 200 ms after this decision, the wrist actually flexed (F). The conscious decision therefore occurred well after the brain had begun to alter its activity in preparation for the movement. And in some cases where the subject reported having prepared the movement internally before executing it (PRP), this lag was even greater: up to 800 ms before the subject consciously decided to make this movement.

After Libet (1985)

How these results should be interpreted became the subject of a debate that continues to this day. If brain activity in preparation or readiness for a body movement was observed prior to the conscious decision to make that movement, didn’t that sound the death knell for free will? Didn’t it show that our consciousness of our own intention to act is really nothing more than an epiphenomenon, an effect of our brain’s activity rather than its cause?

These results were unsurprising to many scientists who already rejected out of hand any form of substance dualism in which free will was endowed with a sort of immaterial autonomy. Indeed, these scientists would have been disturbed by the opposite finding—a consciousness that did not correspond to any brain activity but was capable of inducing an activation of the brain’s neurons, as if by magic. Such scientists were therefore quite comfortable with the idea that conscious will might be a kind of illusion.

But for other scientists, such as Libet himself, consciousness can retain a causal role in our voluntary actions. However, this role is simply that it can exert a control over the movement before it is executed, in the last 150 to 200 ms before the subject’s wrist moves. The decision that was initially made by an unconscious process could then be either approved or overridden by the subject’s conscious will.

According to Libet, the extent of our free will would thus be limited to inhibiting the action, to exercising a sort of “veto power” over its execution. Thus, confronted with the myriad intentions that arise at random from the circuits of the brain, our free will would have the power to reject all those intentions that were inappropriate. Personal responsibility would thus be preserved, because we would still be able to suppress the idea of any socially unacceptable action before we externalized it.

Many criticisms, both philosophical and methodological, have been levelled at Libet’s experiment and at the conclusions that he draws from it.

First of all, some critics have pointed out the difficulty of experimentally testing Libet’s hypothesis of a conscious “veto” function. How, they ask, could consciousness approve or reject a course of action without having assessed its potential consequences first? And if this veto is a conscious act, then it too should require that 350-ms delay to take effect—a bit too long for the 200-ms interval available.

Other critics have directly attacked the dualist assumptions that they saw in Libet’s interpretation, which they said granted an almost magical power to this conscious control.

The main methodological criticisms have involved the use of the revolving spot of light on the circular screen to measure the moment when the conscious decision was made. Some critics have argued that this method failed to account for the time delay that the subjects needed to shift their attention from the spot of light to the conscious decision to move their wrists.

Many other critics have also questioned the choice of a wrist flexion as the behaviour to be observed, on the grounds that it was too simple and repetitive to allow any general conclusions regarding free will or moral responsibility to be drawn from it. These last criticisms have themselves been criticized in turn by Haggard and his colleagues, who reproduced Libet’s experiment and showed that two types of brain waves needed to be distinguished during the interval when the action was being prepared: a first, unconscious wave that corresponds to the triggering of the action (“go ahead, move it”) and a second, conscious wave associated with the type of movement chosen (“move it this way”).

But probably the most radical criticism has come from Daniel Dennett, for whom the very idea of wanting to assign a precise moment to a conscious decision is erroneous. Dennett’s conception of consciousness leaves no more room for a place where the subjective awareness of a stimulus such as a spot of light on a dial could coincide with the awareness of initiating an action than it does for a “self” that might observe this coincidence. According to Dennett, all that exists are brain mechanisms capable of estimating time and responding by words or behaviours to these time estimates. Hence there is no possibility that a “self” might have privileged access to the content of this time estimate and the conscious ability to decide on an action.

But this does not mean that Dennett necessarily rejects any notion of free will out of hand. He does of course reject any form of free will that would emanate from an immaterial power, but he also believes that our feeling of free will is real. According to Dennett, this feeling might be the conscious expression of a faculty that has evolved to let us weigh the pros and cons of the situations that we encounter in which we are presented with multiple options.

The fact remains, however, that this faculty gives us a strong impression that it is our conscious decisions that cause our actions. How can this persistent impression be explained? Daniel Wegner’s experiments showing that a feeling of free will can be induced or, on the contrary, undermined , shed much light on this subject.


These arguments against the notion of free will may seem to shake the foundations of moral consciousness—the ability to make value judgments about our actions and describe them as good or bad.

But the opposite could easily be argued as well. The linguist Steven Pinker, for instance, thinks that the biology of consciousness offers a far more reasonable basis for morality than the unprovable dogma of the immortality of the soul. This biological knowledge could well force us to better recognize the interests of other human beings, which constitutes the very basis of ethics.

Indeed, there is no denying that the countless bloody wars and other conflicts that humans have fought with one another have depended on each side’s denying the other’s humanity. According to Pinker, once we realize that our own consciousness is a product of our brains, and that all other human beings have brains like our own, it becomes impossible to deny the other person’s feelings.

  Presentations | Credits | Contact | Copyleft