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.
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
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
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
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
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.
THE FUNCTION AND EVOLUTIONARY ORIGINS OF
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
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
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,
Adapted from S. Mithen (1996)
in S. Blackmore,
Consciousness: An Introduction (2004).
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
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.
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.
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
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.
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
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.”
THE QUESTION OF FREE WILL
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.
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.
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
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
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.
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