How much of a role does genetics play in who we are? Ignoring physical traits, does it give us our personality? Shape our beliefs? Or are we merely a product of our life experiences? The theory called The Blank Slate has been around for a while and states that we are all created equal. We are all born blanks slates and who we become is shaped by what we are exposed to. It is the age-old nurture versus nature debate.
But what if we inherit more than we think we do? Behavioural genetics is the study of the interaction between the genetic and environmental influences to produce a trait. This book summary looks at genetics closely to evaluate if we are instead a product of modern evolution.
In this book summary readers will discover:
- The three theories of human nature
- Evolution, genetics and our environments
- The weak defences of the Blank Slate Theory
- Why rejecting The Blank Slate Theory is scary
- The three laws of behavioural genetics
Key lesson one: The three theories of human nature
Over the years, three theories regarding human nature have emerged. They are the Blank Slate Theory, The Noble Savage Theory and the Ghost in The Machine Theory.
The Blank Slate Theory is attributed to seventeenth-century philosopher John Lock. The theory is based on the belief that we are born as complete blank slates with no inherent human nature. This means that all the things that make us who we are are being picked up as we grow. So, in other words, all the behaviours we exhibit are a result of the social influences that we are exposed to. Any similarities between people are purely gained through experience and regardless of gender, ethnicity or race. For example, if you had to grow up in a completely different place, with different parents, schools and were exposed to different media, you would most likely be a different person.
The Noble Savage Theory is attributed to eighteenth-century philosopher, Jean-Jacques Rousseau. This theory states that all humans are inherently peaceful and selfless. Any deviation from this is due to their exposure to greedy and violent societies. The third and last theory is the Ghost in The Machine theory. This theory also dates back to the seventeenth century but to another famous philosopher, Rene Descartes. Descartes believed that humans are made up of two systems – the physical body and the mind. People who believe this theory believe that the mind’s complexity can not be explained by mechanical terms.
Key lesson two: Evolution, genetics and our environments
For most of the twentieth century, the Blank Slate Theory was the one that most scientists believed in. It meant that humans had no predispositions to be anything other than good. Any occurrences of racism, sexism or violence could be attributed to outside influences and had nothing to do with the human brain, genetics or evolution. However, with years of research, we know now that this is not true. Cultural behaviour is a part of evolutionary development. Not all of them, though, as some seemed to be based randomly but still have underlying reasons for their decisions. Take something as simple as driving for example. The side of the road people drive on can be seen as cultural behaviour. However, the decision is based on the nation as a whole and the fact that it is for everyone’s benefit if driving is coordinated.
People who believe in the Blank Slate theory believe that the mind has absolutely nothing when we are born. But, if you take into consideration what children learn at an early age, this cannot possibly be true. The ability of children to learn how to speak is a prime example. If the mind was indeed blank, then children would not be able to understand sentences or the meaning of words. They would only be able to simply remember words and not have any inkling to give them meaning. A parrot, for example, will repeat the words it learns. A child, however, has a genetic predisposition to learn the language.
The other thing that modern research has revealed is that there are in fact links between the mind and the physical world. This is the basis of cognitive science. Studies in this area began in the 50s and are based on the very fact that the mind is not a blank slate when we are born. If it were, we could teach people things like language but it cannot be used unless there was another system already in place so that the information can be applied. Then there is behavioural genetics, the area of study into how our genes affect our behaviour. It is based on the fact that the genes we are born with determine some of our characteristics. An example of this is if you consider identical twins that were separated at birth. Even though their upbringing was completely different, they still would have similar characteristics that have nothing to do with their environments.
Key lesson three: The weak defences of the Blank Slate Theory
With all the evidence that modern science has provided, you would think that the Blank Slate theory would already have taken a back seat. However, those who are adamant that it is true, still find defences in the evidence. Take for example the decoding of the human genome. When it was first completed, most people were surprised how few genes it contained – the number estimated was much higher. This gave Blank Slate theorists proof that humans are not as complex as everyone thinks and that the mind could very much be a blank slate as a result. This defence on their part was easily picked apart. When you take into consideration the possible combinations of these genes and the interactions they may have, this gives one a better idea of their complexity.
Another defence is known as connectionism. It refers to the brain’s neural networks and suggests that they can grow connections and recognize patterns much like computer algorithms. However, this has been disproved by artificial intelligence. Artificial Intelligence has shown us that even computers have limits and ones that do not apply to humans. The next defence is neural plasticity which once again deals with the brain and how it changes over time. Someone who has developed a skill like playing the piano will have an area in the brain more developed than those who don’t play the instrument. This is also a defence that can be picked apart as no evidence suggests that such a skill changes the behaviours linked to genes.
Key lesson four: Why rejecting The Blank Slate Theory is scary
The main reason why the Blank Slate Theory still gains traction is that if it is true, it means that everyone is born equal. Any other theory suggests that things like racism, violence and discrimination are things that we are born with. This way of thinking was used in politics saying that anyone trying to disprove the Blank Slate theory was actually in support of a discriminatory system. In the 70s when biologist E.O. Wilson released the book Sociobiology. He faced backlash when he mentioned the common occurrence of tribal warfare. People begin to say that this was no representation of normal human nature and is suggesting that it was promoted genocide.
Thus the biggest fear in believing that genetics plays a role in who we are means that it could be used to justify inequality as it would suggest that certain groups were inferior to others. For example, if people considered crime stats and income levels, this would lead to social discrimination. However, scientists know that genetic differences are not the only factor that determines social status. If someone is born with a genetic disadvantage, society should be responsible for ensuring that this person is not discriminated against. Another fear of abandoning the Blank Slate theory is having to deal with imperfectibility. If humans are born with the genes that make them act in immoral and selfish ways, this is their natural state. Why should we bother fighting against it for any reason? Like men who are born with sexual impulses that can result in sexual assault. In this case, just because it is part of their nature does not mean it has to be tolerated.
The theory also provides everyone with a sense of comfort. This is because they know that if their child is raised in a loving home and receives an education, they will be the ideal child. So if we removed this, how can we make a person accountable for their actions if it is determined by their biology? What would this mean for the law? Would the law no longer apply as the person had no choice in their actions? This argument, however, missed the point completely because it mixed up the concepts of explanations and excuses. You could explain someone’s behaviour due to their biology but that does give them the excuse to carry out those behaviours. Everyone has a sense of right and wrong. Knowingly doing something illegal or immoral has nothing to do with human nature.
Lastly, people fear that if we are only who we are because of our genes and our sole purpose for living is to pass on those genes, what’s the point in living? People look for a greater meaning in life and pure biology will not provide them with that. But who says that one has to overwrite the other? Our genes may provide the biological impulse needed to live but that does not mean you cannot pursue a greater meaning or purpose for your life.
Key lesson five: The three laws of behavioural genetics
Psychologist, Eric Turkheimer put forward the three basic laws of behavioural genetics. They do not support the blank slate theory and rather show the influence that parenting, genes and environments have on human nature.
The first law states that all human behavioural traits are heritable. The second is that the effect of being raised in the same family is smaller than the effect of the genes. The third law is that a substantial part of the variation in complex human behavioural traits is not accounted for by the effects of genes or families. What this third law means is that there is an influence besides family and genes that affects behavioural traits. This is the environment that a person grows up in.
The current estimate of the effects these influences have on our behaviours is genes at 40-50 per cent effect, family at 0-10 per cent and environment at 50 per cent.
The key takeaway from The Blank Slate is:
The Blank Slate theory may have been in existence for a long time but it cannot possibly be true. The human mind is much more complex. The mind already contains some information when we are born. How else would be able to learn as we do and put things into context? The truth is that we inherit more than we realize and as much as this can explain the behavioural characteristics of humans, it does not give us an excuse to behave in ways that are wrong. The sooner we realize this, the less scary it will become to say goodbye to the blank slate theory.
How can I implement the lessons learned in The Blank Slate:
Many people believe that as long as they provide a loving home and everything a child needs, they will grow up being the model child. However, knowing what you do about the influence of genetics and environment you will have a better understanding of how your child’s personality will develop. You don’t have to hold them back or prevent them from joining a certain group, rather talk to them more often about what is right and wrong and allow them to make their own decisions and mistakes. They will grow up better because of it.
