There was a very popular theory for a long time that all human beings were born as a blank slate, that what shaped the way a person behaved and what they achieved was almost entirely conditional on how they were raised. According to this view, there was nothing meaningful set at birth, and everybody could fulfil whatever potential they wanted. Over recent decades this theory has become less and less popular. In Steven Pinker’s The Blank Slate, he makes the case that human behaviour is shaped not just by upbringing, but by biology and genetic inheritance stretching back thousands of years. That is not to say that environment does not matter, it clearly does, but it does not act on neutral material.
These ideas often spill into culture-war debates about good and evil, responsibility and blame. I am not interested in wading into those waters here. This is not about politics or ideology. It comes from something far more ordinary: raising children. My wife and I were talking recently about some of the traits we see in our children, some we absolutely love, and some we find more… difficult, and wondering whether they could or even should be removed. I remember feeling ashamed as a child, even being made to feel ashamed, about certain ways I behaved, my laziness among them, the report was always the same: “he possesses talent, but fails to apply himself” “could try harder”. I’m sure I’m not alone here. Since becoming a father, I see some of those same traits in my own children, and looking back I can see them in my own father as well. I can hardly punish or berate my children for these inheritances any more than I could for them having blue eyes or big feet.
We have come to the conclusion that this is the wrong way to think about children. The task is not to remake them, but to encourage and guide them, given the materials they arrive with.
This piece is not an academic paper. It is a primer, an attempt to explain how genetic inheritance, temperament, culture and society combine to produce the people we become. If you want to go deeper, your favourite LLM can help, and I will also point to some resources at the end.
History
The blank slate idea is relatively recent in the history of ideas. It gained popularity during the Enlightenment, particularly through Locke, and later through 20th-century behaviourism. It’s easy to see its attraction because it allows equal potential from birth and the possibility that humans can be shaped morally, and perhaps that we could engineer a perfect society.
The theory has become less popular in recent times. Part of that shift has come simply from observation: societies and families do not behave as though children arrive interchangeable. Many attempts have also been made to prove the blank slate theory in studies, but have failed to do so. Differences in behaviour, temperament and outcome persisted even when environments were similar.
Pinker’s book did not introduce this change on its own, but it neatly summarised the broader shift in thinking: human behaviour is shaped by genes and environment together. Upbringing matters, culture matters, education matters, but they already had some material to work with.
Temperament
One of the first observable ways we can see temperament in babies is in differences such as their reactivity to noise or how easy they are to soothe. In the same way that the body evolved over hundreds of thousands of years, the nervous system has evolved as well. Genes influence ranges, not precise amounts. In the same way that the average man is faster or stronger than the average woman, genes give a wide scope for temperament, preferences and threat responses. This is not just anecdotal, it shows up time and time again across cultures and populations. There is a famous study by Jerome Kagan on inhibited (strong reactions to new people, distress in unfamiliar settings, preference for predictability) versus uninhibited (calm reactions to new situations or settings, moving readily towards stimulation) infants. He showed that highly reactive, inhibited babies often became cautious children and low-reactive babies often became exploratory and bold. Again, these were ranges rather than rules, it wasn’t always the case, but the trend was in that direction.
You’re just like your mother
There have been more than a few times since my children were born that I’ve been struck by the way they look or act like their ancestors. Some of it is very cute, like the way my daughter looks like my mum sometimes, others not so much. Both my daughter and I share a body shape that finds it easier to gain fat than is ideal. My wife and my son share many physical similarities too, but I don’t share many with him, nor my wife with our daughter.
Temperamentally the same is true. My daughter and I are very good at relaxing, while my wife and son struggle to switch off easily. I see this very clearly with my wife, her three sisters and their parents, they react in similar ways to certain situations. If I’m feeling in a particularly masochistic mood I might point some of this out to her. The human species has, over millennia, evolved to suit its surroundings, both physically and mentally. In families we see this most clearly: inherited tendencies shaped and softened by habits, stories and ways of doing things, and what happens at this small scale is repeated, more slowly and more formally, across whole cultures.
Families at scale
Think about the way you were brought up, the rules your parents had for you, and the rules your grandparents, aunts and uncles passed down. All of these explicit rules, and many of them felt harsh or ridiculous at the time, helped shape the way you see the world and how you behave in it. Many only made sense later, once you had children of your own, or at least knew people who did. The things you were praised or scolded for did not disappear, they stayed with you and still shape you today.
Society does this at scale, over much longer periods of time. These rules and expectations change slowly and unevenly, but they persist. What we loosely call ‘Britishness’, even if it is hard to define precisely, is a product of this process. In the same way that families develop their own ways of doing things, what you might call ‘Smithness’ or ‘Jonesness’, societies develop shared customs and expectations that hold people together and allow them to live alongside one another.
Your biology is innate, we can see that from birth. It then meets your family, where it is shaped to greater or lesser effect, and as you grow you encounter other people who teach you, often implicitly, how to behave. School is usually the first formal meeting with society, where you learn that you cannot steal Emily’s dolly, throw a train at Connor’s head, or pick your nose and eat it. From there you move into wider and more varied social worlds, each with different expectations, which people meet in different ways.
That variation matters. People respond differently because they start differently. They arrive shaped by their genes and their early surroundings, and although you will find people you recognise yourself in, people you feel immediately at home with, you will never find another person who is quite the same as you.
So where does this leave us?
As tempting as it is to try and change our children (or the children we meet and care for) into something we think they should be, it isn’t going to work. It hasn’t worked for millennia, and it didn’t work on you. That doesn’t mean there are no rules. Children need boundaries, they need to be kept safe, and they need to learn how to exist alongside others. Customs and traditions matter, but children have to be allowed to understand what those things mean to them, and to grow into them in their own way.
This is hard. I fail more than I succeed trying to live by my own rules. I still want to grab mine around the neck like Homer Simpson and throttle them, and when I see their peers changing my sweet little babies I almost cannot resist the urge to push back and try to make them mine again, but I know it won’t work. The forces of biology and society, of both nature and nurture, are too strong.
Our job is not to manufacture children. It is to guide them, to keep them safe, and to help them understand the world they are growing into.
Definitions
Temperament
A set of biologically influenced tendencies in how a person responds to the world — for example, how reactive they are to new situations, how easily they calm down, and their typical level of activity or caution. These differences are observable early in infancy and remain relatively stable over time.
Behaviourism
A psychological approach dominant in the early 20th century that treated human behaviour as learned entirely from the environment, often ignoring internal biological factors. The idea of the “blank slate” in psychology has roots in behaviourist thinking, though modern science understands both genes and environment shape behaviour.
Blank Slate (Tabula Rasa)
The idea that people are born without built-in mental content and that all behaviour and personality traits come from experience and environment. This view has declined in popularity because evidence shows biological and genetic factors also shape who we are.
Further reading
· The Blank Slate: The Modern Denial of Human Nature, Steven Pinker — on how science challenges blank-slate assumptions.
· The Nature of the Child, Jerome Kagan — foundational work on early temperament.
· Nature vs Nurture overview (Wikipedia) — evidence showing both genetics and environment matter.
· Not in Our Genes, Lewontin, Rose & Kamin — critical perspective on genetic explanations.
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