twinsinair One of the most classic arguments: is it nature or nurture which more determine who we become? Is our life somehow predetermined or laid out in our predispositions, or can environmental factors compensate for even the most radical genetic tendencies?

The question has also been answered a thousand times, most often with the answer that both environmental and genetic factors contribute to who we are and our personality or our “behavioral phenotype.” The same exact experience can be perceived and understood completely differently by two individuals, but is the root of this difference based in genetics or learned patterns of thought/behavior?

The answer is a little more complicated than just saying it is a mix. Genetic factors give us the “limits” of what we can become: the borders of what we can turn into. In the same way that being a human at all gives us certain limits and opportunities, genetics lays out individual theoretical boundaries of development.


Pablo Pineda, who obtained a university degree in education despite having down syndrome

You can think of your personality like an embryonic stem cell: undefined, with the possibility of turning into everything that is held within. Whether one of the resulting cells turns into a liver or a kidney, or cancer, is based on the signals that the cells get: both from within its own programming and based on the context. Whether someone with high stress tolerance and low emotional processing turns into a monk or a psychopath is also primarily controlled by the environment, instead of genetics.

Genetics determines the “tipping points,” how much of one type of stimulus will lead to a certain reaction. An example of this would be how a person reacts to eating refined sugar: do they develop type 2 diabetes or will they be perfectly fine? The question is not even just a question of inherited genetics, and how much or how often the person eats refined sugar, but also potentially of the coupling of genetic expression with previous experience (and gene (de)activation). We also have to keep in mind that most personality traits are epistatic, meaning they are controlled by a range of different genes that interact with each other.

Picture yourself as standing on a floor of differently colored tiles, with each tile around you representing a different choice. With each tile you step on, you change the probabilities of what you will become, what sickness or what chances are more likely to lay in your path. How you were taught to understand the different colors (which represent the actual content of your decisions), or even which colors you can see, will influence what steps or decisions you make.

To put this in more abstract terms: decisions, experience, and genetic influences stand in a kind of feedback loop. Genetic predispositions increase the chances of making certain decisions, which themselves then increase the chances of getting certain conditions or having a certain personality types. Of course, this also means that learned habits and perspective, ways of thinking and judging our decisions, can make the difference between the painter and the graffiti artist. A big chunk of our personality is definitely genetic, but this is not the only deciding factor.genes-environment-choices

How well you do in school is not just a question of intelligence (which is itself probably at least 50% genetic), but an entangled mix of dozens of genes and a nice dose of previous experience and perspective. Using genetics as an excuse for doing, or not doing, anything is a lame determinist escape from responsibility. When someone (Pablo Pineda) with down syndrom can graduate from college, what could be a good excuse for not paying attention or learning? When people without emotion can be caring and responsible, what could be anyone’s excuse for acting like a psychopath?

We are both subject to our genetic limits, and co-authors of our future. Even if we cannot control what impulses we have, even if you have too much or too little emotion: we can all understand  what we should basically be doing. We can all understand that we can build more long term prosperity through love than fear, and more understanding and growth through empathy (even if only cognitive and not affective) than objectification. Although we cannot avoid the limits of our potential (someone with autism is not going to ever experience emotions like a neurotypical person), we can influence what direction we are moving in. In the end, genetics only gives us probabilities and possibilities: what we do with them is up to us.