Are We A Blank Slate? On Neonatal Brains, Nature vs. Nurture And Psychotherapy.

When it comes to nature vs. nurture, where do you stand?

These newborn brains look so pristine, don't they? Seeing this, one might easily be comforted by the thought that, after all, we really are born as blank slates. However, what certainly appears to be a blank slate at birth can, in fact, be very deceptive.

Estimated heritability of psychiatric, behavioral, and neurological disorders (BIP, bipolar disorder; SCZ, schizophrenia; ADHD, attention-deficit/hyperactivity disorder; MD, major depression; ANX, generalized anxiety disorder), behavioral (AN, anorexia nervosa; AUD, alcohol use disorder; CUD, cannabis use disorder), or neurological (ASD, autism spectrum disorder; AD, Alzheimer's disorder; OCD, obsessive-compulsive disorder; TS, Tourette's syndrome) disorders.

The blank slate hypothesis suggests that, in the nature vs. nurture debate, human nature is entirely shaped by nurture (environment) and 0% by nature (genetics). The branch of science that studies how much of what we are is due to nature (genetics) versus nurture (environment) is called behavioral genetics (or psychiatric genetics when the traits studied are specifically related to mental health). Over the past decades, research in this field has consistently demonstrated a significant genetic influence on mental health conditions, as shown in the graph from a 2021 paper. The differences in heritability estimates on the graph (pink and purple) result from different methodologies used, but this is beyond the scope of this post and could be a topic for another (particularly geeky) blog post.

Similar results abound. It appears that the heritability of most mental health conditions ranges between 20% and 70%. This genetic influence is significant.

Some simpler estimated heritability graphs can be found here.

To name just one example, whoever has worked with a client presenting with Social Anxiety Disorder is more than likely to have identified precursors in the client's family history.

It seems to me, however, that there remains a strong, if not dominant, undercurrent within psychotherapy that, while not always explicit, ultimately embraces the blank slate hypothesis and remains ignorant of (or in denial about) the facts concerning the heritability of mental health conditions.

A good example of this position is the book Not In Your Genes by Oliver James, which garnered lots of publicity in psychotherapy circles some years ago. It is sometimes cited by therapists as "proof" in favour of the blank slate hypothesis.

I come from Transactional Analysis (TA) tradition, and I will quote Claude Steiner to corroborate my argument. If you come from a different psychotherapeutic modality, I am sure you can think of an equivalent, if your modality is person centred, gestalt or psychodynamic. In his book "Scripts People Live", Steiner gives his take on "I am OK, you are OK" principle by saying:

"Human beings are, by nature, inclined to and capable of living in harmony with themselves, each other, and nature. If left alone (given adequate nurturing), people have a natural tendency to live, to take care of themselves, to be healthy and happy, to learn to get along with each other, and respect other forms of life".

I believe Claude means well, but a glance at human natural history proves his thinking inaccurate. Humans were, indeed, originally left to their own devices and nature, and look what happened. My point with this extract is to illustrate the tone often heard in discussions about "original" and "good" human nature, surprisingly (or not!) common to psychotherapy

If you ask me, it is all a little too reminiscent of the Garden of Eden and the evil snake-and-apple situation.

I think I understand where they are coming from though. It can almost feel as though if science "declares" something to be genetic (nature), then it means there is no hope of changing it. Psychotherapists could therefore be understandably "resistant," to use a psychodynamic term, to the idea of mental health falling into the domain of genetics and scientific inquiry in general.

But that is a misconception, and the whole dichotomy goes away once we place ourselves in front of a different lens.

But what if the nature vs. nurture whole was a false dichotomy, when it comes to psychotherapy?

I believe that we can overcome (almost) any adversity and cultivate incredible resilience that defies all odds. In fact, I believe, this is one of the foundation principles of my work with clients. But surely, understanding the role of nature (genetics) in this equation can only help in this worthy pursuit.

Everything is possible. Absolutely. But knowing what truly stands in the way of the "everything is possible" destination can surely only help in the effort of getting there, right?

Bill Cornell uses this beautiful turn of phase to describe the similar dilemma in his article "Truth Of Love or Love Of Truth". So where should we stand in this dilemma, as psychotherapists? Well, each one of you has to make up your mind on that important question, but I know where I stand. I love the truth. I will explain why I think that position might be in the best interest of our clients too.

Let me make my case using a very abstract travelling metaphor. Imagine that you want to go from a point A to point B. And there is an (physical) obstacle X on the way to get there. There are two possible strategies:

1. Pretend that X does not exist, and try to get through the physical obstacle anyways (while possibly confabulating another reasons why it is not easy to get from A to B).

2. Acknowledge X. Find a way around X. Get from A to B.

What would be your choice of strategy?

Now see if you feel the same thinking could apply to the nature vs. nurture debate in psychotherapy, especially in the light of the research findings we discussed. In other words, is acknowledging the part of nature (X from the metaphor) helping or hindering client's progress from A to B?

You will have guessed, to me, the answer is still the same.

Knowing is good. Science is friendly.

But you can let me know your thoughts on this important question via the usual channels. As always, thank you for reading.

If you're interested in going deeper into the nature vs. nurture discussion in psychotherapy, please let me know. I am currently deliberating with myself whether to prepare a workshop about this so a "Yes, I 'm interested" or a "Please, no!" would greatly assist me in decision making.

If you liked this, for updates and more of the similar follow me on BlueSky or Twitter or subscribe to my mailing list.