What is culture? It seems a trivial question, but it is anything but. Culture is commonly defined as ‘the body of knowledge, values, beliefs and behaviours that an individual acquires through study or that a social group shares and passes down over time’. A definition so thoroughly normalised that it seems neutral and complete; a pity it is neither.
Reading the definition more closely, one immediately notices that it is heavily influenced by blank slate theory: the idea that goes beyond John Locke’s tabula rasa — the philosophical concept according to which the human mind at birth is a blank sheet, devoid of any innate knowledge — and takes it to an extreme, asserting that character, behaviour, psychological differences and inclinations are also entirely products of environment and upbringing.
And it is precisely blank slatism that makes this definition wrong, since it implies that any individual can make a people’s cultural artefacts their own simply by studying them or being transplanted into a particular cultural system.
Contesting this theory is not easy, since it represents one of the most untouchable dogmas of the twenty-first century. Questioning it often carries the risk of exclusion from the scientific community: one need only consider that, in various countries, certain research potentially capable of undermining its premises is obstructed, prohibited or relegated to the margins of debate, in an attempt to preserve the hegemony of the blank slate. Despite these restrictions, however, there are several studies that can be cited and that call its theoretical integrity into question:
One of the best-known studies in this field was conducted by Bouchard et al. in 1990, entitled ‘Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart’. The research involved more than 100 sets of twins separated during childhood and raised in different families, subjecting them to an intensive series of psychological and physiological assessments over approximately one week, covering intelligence, personality, temperament, occupational and recreational interests, and social attitudes. The authors estimated that around 70% of the IQ variance observed in the sample was associated with genetic differences. Moreover, for many personality and temperament traits, as well as occupational and recreational interests and certain social attitudes, monozygotic twins raised apart were almost as alike as monozygotic twins raised together.
In his book Blueprint: How DNA Makes Us Who We Are, Robert Plomin analyses decades of behavioural genetics research, concluding that all psychological traits show a significant and substantial genetic influence. According to Plomin, the average heritability of psychological traits is around 50%, while the shared environment — the family experiences common to members of the same family — accounts for only a very small proportion of individual differences in adulthood. Plomin then concludes that ‘DNA is the major systematic force, the blueprint, that makes us who we are’.
Modern scientific literature now clearly shows that many of the traits that characterise our behaviour, personality and abilities have a significant genetic component, seriously challenging the blank slate theory. But what if I told you that the conclusion might be even more radical? What if virtually no human psychological trait were entirely independent of genetics?
A trait is simply a phenotypical characteristic, which may be structural, physiological, cognitive or behavioural. It is the concrete outcome through which genetic makeup, interacting with development and the environment, manifests itself in reality. Together, these traits constitute what we call the phenotype: the set of observable and measurable characteristics of a living organism. In this sense, the phenotype represents the contingent and temporary form through which genetic makeup enters into a relationship with the world and, through reproduction, can project itself into the future.
One might think that the external environment acts as an autonomous creative force, independent of the organism. In reality, however, it is necessary to distinguish between the material world and the environment that is biologically relevant to a particular organism. The environment does not, in fact, exert its effects identically on everyone: what matters is how it is perceived, interpreted and transformed into behaviour by the organism’s perceptual, cognitive and behavioural mechanisms, the so-called Perceptual, Cognitive and Behavioural Mechanisms (PCBM).
PCBM are the organised systems through which an organism perceives information from the outside world, interprets it, assesses its relevance and produces appropriate behavioural responses. In this sense, the environment cannot simply be regarded as an objective agent that is identical for everyone, because the same external stimulus can take on different meanings and produce different consequences depending on the characteristics of the organism that encounters it.
It is therefore useful to distinguish two levels:
• Material world: climate, predators, food availability, pathogens, social structure and all the other physical and biological conditions external to the organism. Over the generations, these factors constitute part of the selective pressures that help determine which genetic variants increase or decrease in frequency within a population.
• Ontogenetic environment: the environment as it is actually experienced by the individual organism during its development. At this level, what matters is not only the world ‘as it is’, but the world as it is perceived, filtered, interpreted and made biologically relevant by the individual’s PCBM. The same material world can therefore constitute profoundly different ontogenetic environments for different organisms.
The organism, then, is not a blank canvas on which the environment passively writes. It is, rather, an evolved system of recursive and continuous disambiguation: it receives a multitude of signals from the outside world, reduces their ambiguity, filters, selects and interprets them through a cyclical and endless process.
The organism does not deny, therefore, merely submit to the environment, but actively probes and monitors it in search of biologically relevant information for its own fitness, transforming that information into perceptions, evaluations and, ultimately, behaviours. The relationship between organism and environment is thus not unidirectional, but dynamic and reciprocal: the environment provides information, while the organism determines which of it is relevant and how it should be translated into action.
If everything were rigidly determined by genetics, how could we explain improvements in intelligence quotient, changes in character or, more generally, the modification of traits over the course of a lifetime?
The answer is that the genome does not necessarily produce a single fixed outcome. Instead, it helps define a structured set of possible phenotypic expressions in response to different conditions: what biology describes through the concept of the reaction norm. This does not mean that the environment ‘creates’ the organism from outside. Rather, it means that the organism possesses evolved capacities to respond in different ways to different inputs.
A plant, for example, may grow taller or shorter depending on the availability of light, water and nutrients, and on the characteristics of the soil. But its sensitivity to these stimuli, the way it processes them and the range of biologically possible responses depend on its genetic and physiological organisation. The environment therefore modulates the expression of the phenotype, but does so by interacting with an organism that already possesses a particular biological architecture.
This perspective is sometimes associated with a form of biological realism. Contrary to what one might think, recognising the importance of biology does not necessarily imply rigid determinism. Even complex capacities such as consciousness, deliberation and what we call free will presuppose the existence of biological structures that make their development possible. They do not exist independently of the organism: they emerge from it.
From this point of view, changes in traits can take at least two different forms. Over an individual’s lifetime, phenotypic plasticity allows the organism to modify some of its characteristics in response to the conditions it encounters. On an evolutionary timescale, by contrast, the frequencies of genetic variants and their associated traits can change over the generations when particular characteristics have different effects on the survival and, above all, the reproductive success of the individuals who possess them.
What, then, is culture?
Biological realism regards it not as an autonomous entity existing alongside biology, but as its direct extension.
The first mistake to avoid is confusing culture with its artefacts. When people speak of culture, they almost always think of traditional clothing, art, cuisine, fairy tales,
myths, languages or festivals. These things, however, are not culture: they are its visible expressions. They are the products of a process, not the process itself.
This is the same misunderstanding that arises with the concept of environment: what appears on the surface is taken and treated as an independent force, detached from the organism’s biology. The etymology of the word already offers a more accurate indication. ‘Culture’ derives from the Latin verb colere, ‘to cultivate’. It denotes not an object, but an action repeated over time.
Transposed into the social sphere, culture is the process by which one generation cultivates, socialises and educates the next. It is the way a group transmits what it ‘holds in common’ across generations.
And the most fundamental thing held in common is not a set of norms, values or symbols: it is a shared genetic inheritance. Everything else — practices, institutions, systems of meaning — is built on and around this foundation.
This is why culture cannot be treated as software that can be installed indiscriminately on any population. It is the continuous process through which a group reproduces itself from its own biological substance.
This distinction between process and artefacts allows us to answer another important question: to what extent are cultural elements bound to the biological substrate of the group that produces them? Not all cultural artefacts are rooted to the same degree. It is useful to distinguish at least three levels of depth.
At the deepest level lie basic moral orientations, patterns of trust (generalised or limited to one’s own group), the relative importance assigned to loyalty, authority, purity or fairness, time preference (how much the future is valued relative to the present), and ways of socialising children. These traits are the most stable and the most difficult to modify over short periods. They change slowly, particularly if the demographic substrate changes or if environmental pressures remain constant for many generations.
At the intermediate level lie preferred family forms, sexual and gender norms, attitudes towards authority and institutions, the degree of religiosity or secularisation, communication styles and the relationship between the individual and the collective. Here, plasticity is greater: the developmental environment and prolonged contact with other cultures can produce calibrations. Yet they remain constrained by the deeper levels and do not move in every direction with equal ease.
Finally, at the superficial level we find cuisine, clothing, music, folklore, symbols, vocabulary and fashions. These are the most plastic elements. They can be adopted, hybridised or abandoned relatively quickly. Even here, however, the way they are valued and transmitted remains influenced by the underlying levels.
Superficial artefacts can therefore mix and change without much resistance. But if the deep and intermediate levels remain different, the process of cultural reproduction continues to generate divergent trajectories. This is precisely why sharing certain outward practices or living under the same laws does not automatically produce a single culture.
Once it has been established that culture is a process of reproduction bound to a group’s biological substrate, it becomes possible to address a more precise question: how genetically differentiated are human populations, and what consequences does this differentiation have at the cultural level?
One of the most widely used tools in population genetics for measuring these differences is the Fixation Index, or Fst. This index quantifies how much the allele frequencies of two groups differ from one another. In simple terms: the higher the Fst, the greater the genetic distance.
The values are interpreted as follows:
• below 0.05 → low differentiation, typical of populations within the same continent;
• around 0.10–0.15 → moderate/high differentiation, indicating highly isolated groups;
• above 0.15–0.20 → high differentiation.
The available data show that Fst is around 0.11 between Europeans and East Asians, around 0.15 between Europeans and sub-Saharan Africans, and around 0.19 between East Asians and sub-Saharan Africans. These are not superficial differences. Genome-wide studies have shown that the most differentiated genes also include those linked to the development of the nervous system.
These genetic distances are not accidental: they are the result of long periods of geographical isolation and adaptation to different selective pressures. The Sahara Desert, for example, acted for tens of thousands of years as an almost impassable barrier, drastically reducing gene flow between the populations to its north and south. Under conditions of prolonged isolation, human groups continued to adapt to different environments, ways of life and demographic pressures, developing average profiles of cognitive traits, temperaments and value orientations that were not identical.
If culture is the process by which a group reproduces itself from its own biological substrate, then genetic differences of this magnitude explain why profoundly different cultures exist and why they are not interchangeable. It is not merely a matter of habits or superficial traditions, but of different ways of perceiving, evaluating and organising social reality, rooted in distinct evolutionary histories.
This is precisely why integration understood as the simple coexistence of demographically significant groups, without a process of substantial assimilation, tends to fail. It leaves different cultural processes operating side by side within the same political and institutional space. The result is not a unified culture, but the coexistence (often tense) of parallel reproductive trajectories.
A question naturally arises: can an outside population become part of another group’s cultural process? Yes, but only under certain conditions. Assimilation can
take place effectively above all with small numbers and over long periods. In such cases, the newcomers (and especially their descendants) are absorbed through intermarriage, socialisation within the host group’s institutions and networks, and the progressive dilution of average differences in traits. The intergenerational process of ‘cultivation’ remains dominated by the original group, the genetic substrate changes only marginally and gradually, and culture, understood as an extended phenotype, can continue to reproduce itself in a recognisable form.
When, by contrast, the numbers become large and concentrated, the substrate itself changes significantly. At that point, it is no longer a matter of assimilating someone into an existing process, but of having several cultural processes operating simultaneously. The cohesion of the original group tends to weaken because the mechanism that reproduced it is no longer dominant.
Before concluding, it is useful to address two objections that arise naturally from this line of reasoning.
The first concerns cultural plasticity. If culture can change, and the secularisation of religious ethical precepts is an obvious example, why should multiculturalism not work?
The answer lies in the nature of this change. Biological realism does not claim that cultural precepts are immutable. It claims that they change within limits and through calibrations mediated by the PCBM of a particular biological substrate. When the modern environment (low mortality, abundance, contraception, anonymity, declining supernatural belief) altered the costs and benefits of old strategies, many traditional religious precepts lost their force. They did not, however, vanish into thin air: they were largely replaced by new moral systems (autonomy, equality, inclusion) that perform analogous functions for different phenotypic clusters.
Change, then, does happen. But it happens in a biased and constrained way. It does not mean that cultural processes carried by different substrates, left to operate in parallel and in significant numbers, spontaneously converge into a single process. Plasticity explains how a culture evolves; it does not explain why several cultures should automatically merge.
The second objection concerns the ontogenetic environment. If the environment in which an individual grows up influences their development, why not regard it as an independent force capable of shaping culture?
Here it is necessary to go back to the distinction already introduced. The ontogenetic environment is not the ‘objective’ material world, but the world as it is perceived, filtered and made relevant by the PCBM of a particular organism. Two individuals (or two groups) with perceptual, cognitive and behavioural mechanisms that differ on average, placed in the same physical location, do not inhabit the same environment. What is salient, threatening or attractive to one may be irrelevant to the other.
The environment, therefore, does not act autonomously and identically on everyone. It acts through biologically organised systems. It is not an external cause independent of biology: it is
already the product of the encounter between the material world and the mechanisms of the organism that interprets it.
At the end of this journey, the initial question, ‘what is culture?’, receives an answer different from the usual one.
It is not a body of knowledge and values that can be acquired and transmitted like software. Nor is it a purely environmental construct, detached from the biology of those who produce it. It is the process by which a group reproduces itself over time, from its own genetic substrate and through the mechanisms by which its members perceive, evaluate and organise the world.
Cultural artefacts, from the deepest norms to the most superficial practices, are expressions of this process, not the process itself. Some of them are plastic and can change relatively easily; others are more stable, because they are rooted in differences in traits with long and, in many cases, distinct evolutionary histories.
This perspective does not deneither cultural change or the influence of the environment. It does, however, place them within precise biological limits. It explains why different cultures are not interchangeable, why the integration of demographically significant groups without substantial assimilation tends to produce parallel processes rather than a unified culture, and why assimilation, when it occurs, requires limited numbers and long periods.
Biological realism offers a more sober view of what culture is and what it can realistically become. In an age that continues to treat cultural differences as mere constructs or as simple products of upbringing, recognising their connection to the biological substrate of groups is an act of clarity.