We have 87 thousand million neurones, despite which, our cognitive capacity is actually more limited than we perhaps think: the brain has its limits and research into our imagination, the trauma of a sick brain, and how we perceive the world around us, reveals a variety of relatively reduced cognitive capacity. Why do activities such as the arts and science help us counteract the limits of a person’s brain function?
By Andrea Slachevsky
Thinking about neuroscience, art and science raises questions about the role of cultural activities and individual’s brains. It might seem to be a rather rhetorical question: it’s obvious that art and the sciences are fundamental to encourage better interaction between people, and better standards of living. But a closer look at the numbers brings to light an apparent paradox: every human brain has 87 thousand million neurones, while on earth there are 7 thousand million human beings. So the proportion of neurones of each brain to the number of people on the planet at the moment is 10 to 1; and in 1900 it was 58 to 1. Despite the huge number of neurones, which we hope would give us potentially incredible intellectual capacities, in reality our capacity is significantly more limited than we think: the brain has limits. Why do collective intellectual activities, such as art and the sciences, that have emerged over the centuries, help us counteract the functional limits of the human brain?
One of the first things to do when examining the human brain is to ascertain the statistics of its constitutive parts, which are truly astonishing. The brain is relatively small, weighing between 1.300g and 1.400g, that is, 2% of the human body, but it consumes 20% of the oxygen and the calories used by the organism. As mentioned above, this nut-shaped little structure is made up of 87 thousand million neurones, the best-known cells of the central nervous system. But these neurones aren’t isolated, they’re surrounded by glial cells, which researchers used to think were merely the glue between the neurones, but which researchers have since shown to function as a framework for the neurones. In recent years glial cells have emerged as essential for the healthy functioning of the brain.
The proportion of glial cells to neurones varies depending on the evolutionary status: from 1 per 6 neurones in the brain of leeches, to 1 glial cell per single neurone in the human brain, according to research by the Brazilian neuroscientist Suzana Herculano-Houzel. So the human brain is made up of 174 thousand million cells whose functioning determines the brain’s properties and capacities. The neurones and the glial cells communicate and their properties are fundamental for the transmission of information between them. Each neurone is capable of establishing up to 10.000 connections with other neurones, and it is estimated that the brain has about 125 trillion points of contact between neurones, called synapses. Through these connexions the neurones and glial cells make up networks of varying sizes and complexities, interwoven with each other through micro-networks, made up of contiguous neuronal elements, and macro-networks in which the neurones and glial cells from different areas of the brain interact. The vast number of possible interactions between the 174 thousand million neurones and glial cells could spawn an almost infinite variety of brains, each with their different networks and connective pathways. But this heterogeneity doesn’t occur. The connections between the neuronal elements aren’t arbitrary but are established according to certain maps. The project The Human Connectome has studied the cartography of the neuronal networks, and shown that the connections of the human brain are organised according to certain patterns, ranging from the multiple micro-networks to the existence of very large macro-networks that make up the neuronal substrata of the cognitive and behavioural capacities.
The 87 thousand million neurones of the human brain, with their 125 trillion points of contact, aren’t organised in a multiplicity of brain networks that differ from brain to brain, nor does their activity show a variety of different cognitive or behavioural capacities. Quite the opposite, research shows that the imagination, the trauma of a sick brain, and how we perceive the world around us, reveals a relatively reduced variety.
The imagination, which we could consider disruptive is, in reality, limited, as the description of monsters in the 16th century shows in the book La logique du vivant (“The Logic of the Living”, 1970), by the French doctor François Jacob (1920-2013). He writes that “the description of living beings in the 16th century is full of a huge variety of monsters of all sorts… These monsters always reflect the known; not a single one is not reminiscent of something known, even though it might be completely different from what we see here or elsewhere, only that instead of resembling one being they resemble two, three or sometimes even more beings. Its parts belong to different animals. So there is the “monster with the head of a bear and arms of a monkey”, the “man with hands and feet of a donkey”, the “boy with a face of a frog”, the “dog with the head of a chicken”, the “lion covered in fish scales” or the “fish with the head shaped like a bishop”, and any other imaginable combination. The monsters always share characteristics, but these have become variedand don’t fit into the normal games of nature”.
In conclusion, the act of imagining the most terrifying thing possible doesn’t mean creating something completely new but is instead like playing a game of Lego, combining the known pieces to create a new reality, but within the realm of the known or possible. The respect for this framework repeats itself in the contemporary imagination of film about aliens. For example in Plan 9 Of Outer Space (1959) by Ed Wood, or ET (1982) by Steven Spielberg, or Mars Attack (1996) by Tim Burton, the aliens are all reminiscent of 14th century monsters, in this case variations on the human form: elongated necks, heads with different protuberances or deformations, limbs that are added or taken away. But in the end they always take the shape of the deformed human body. It seems that we don’t have a great capacity for creating something totally disruptive or different from the already known, despite the immense variety of life, in which more than 8 million different species have been described.
The sick brain also shows the limits in terms of the variety of phenotype expressions, that is, in how a cerebral, psychiatric or neurological pathology manifests itself. Taking the case of hallucinations, a phenomenon that at first can seem completely anomalous or grotesque: the conviction of perceiving something that doesn’t exist in the outside world. But hallucinations are also present in people who have no sickness of the brain. A poll of 31,261 people in 18 countries, published in 2015 in the JAMA Psychiatry magazine by John McGrath and other researchers from the University of Queensland, Australia, showed that 5% of people report having had hallucinations despite not consuming drugs or having any mental illness. A phenomenon that at first appears absolutely pathological and incompatible with normality –perceiving the non-existent– isn’t always a symptom of illness.
Hallucination in particular circumstances, or characterised by their frequency or intensity, or their association with other symptoms and inability to distinguish the reality from hallucination, are signs of a pathological manifestation. In the second half of the 19th century the English neurologist John Hughlings Jackson (1835-1911) wrote that the manifestation of brain illnesses reflects either a loss or an exaggeration of normal brain function. Multiple symptoms of neuropsychiatric illnesses aren’t the de novo creations of a sick brain. In conclusion, even a sick brain seems to behave according to certain determined patterns.
Apart from facial recognition, with which we identify the subtle variations of one face to another, our perception of our surroundings privileges the detection of generalities above that of difference. The cognitive scientists Steven Sloman and Philip Fernbac write in The Knowledge Illusion. Why We Never Think Alone (2017) that “The mind is not built to acquire details about every individual object or situation. We learn from experience so that we can generalize to new objects and situations. The ability to act in a new context requires understanding only the deep regularities in the way the world works, not the superficial details”. Furthermore, in the process of perception there is an interaction between the information coming from the surroundings and the representation that is already present in the brain. In her novel Forest Dark the North American writer Nicole Krauss deftly describes the brain’s mechanism for perception as “a flow of associations and perspectives stored in the brain that it uses every second to fill the gaps and give meaning to what the eyes transmit”.
So it would appear that despite the brain’s huge number of component parts and their multiple connections, we have a relatively limited number of behavioural expressions, both in a normal and in a pathological brain. Nor is this huge number of component parts reflected in a capacity to detect the many components of our surroundings, but rather the opposite: we are blind to diversity, privileging generalisations and seeking out patterns that confirm our preconceived ideas, to the detriment of novelty, minimising information that could jeopardise what we think we already know.
However, these brains, limited in their scope, “whose principal function would seem to be to create coherence at any cost” as Nicole Krauss writes, interact with each other, and in this process they appear to be capable of creating the tools to help them surpass the limits of each individual brain and examine the biased perceptions of other brains. Which is how art and science takes root in humanity. Science, in broad brushstrokes, could be defined as an activity that creates the necessary conditions to question our biased perceptions and interpretations: science creates the conditions for the generation of knowledge that isn’t based on individual conclusions.
What is more, science has helped us understand how our brains function, to understand our mistakes in perception, and to see why we can’t trust in the knowledge that emerges from an individual brain. Perhaps one of science’s principle virtues is that it helps us question our own brains: “That’s where science’s beauty lies. You set out on a path full of darkness and curiosity, without knowing where you’ll find the solution to the problem that led you to take this path in the first place” writes the Israeli editor Benny Barbash in Little Big Bang (2011).
Art, on the other hand, that can be thought of as an individual activity, gains meaning because the artist interacts with and creates with others for others –artists and non-artists– and in relation to the mass of art history that is alive in society. Perhaps one of art’s greatest achievements, beyond aesthetic considerations, is what the French writer Patrick Chamoiseau describes in La matière de l’absence (“The Substance of Absence”, 2016): “the great artists, the great works, set up an open door to the horizon without horizon on the unthinkable. That’s what is important in the artistic gesture. Not the meaning offered, nor intellectual poverty that soothes us, but really a door that opens and never closes again, allowing us to perceive the infinite energy of what is impossible to imagine”. Art helps to break down the false truths that are created in the one narrow perspective of a single human brain.
The 174 thousand million neurons and glial cells seem to stick together in a finite number of component parts, which make us human beings creatures with poor imaginations and experts in detecting that which confirms us in our beliefs. But at the same time those 174 thousand million neurons and glial cells communicate with other similar brains, and that multiplication of communication can create the conditions necessary for heterogeneity to emerge – as though the power of those 174 thousand million elements were liberated in our brains. But perhaps the most important consideration is that the dialogue between those multiple brains enables the change in perspective that allows for scientific and artistic activity.