Why genes + environment ≠ Us

A battle against Tourette's syndrome suggests that there is more to human beings than evolutionary biology tells us.



"Organisms are determined by their genes and the environment" is a slogan in biology classes all over the world. This is known as "genetic determinism" and is one of the pillars of the important "new synthesis" interpretation of evolutionary theory. Its drawback? It's not true!

A personal story will clarify what I mean. Let me first give you some background. I have always had many interests. After my first year of studying biology at university, I felt I needed something more challenging, so I decided to start mathematics as a second major. At the same time, I pursued several hobbies, including playing the piano, singing in two choirs, and playing handball, which included two training sessions and one match per week. On Saturdays, I had a job as a mailman. In short, my days were full. But when in the second year my studies became more challenging, everything started to add up and strange things began to happen.

During a bike ride to my piano lesson, my head suddenly jerked to one side. Nothing major, but it was rather strange. Other small things happened: I would suddenly inhale intensely; my belly muscles would suddenly contract; I would emit a sound I did not choose to make. These things usually occurred when I was relaxing on my own and I did not pay much attention to them. But as time went by, the symptoms became more intense. I remember I was most startled when a few years later I suddenly pulled myself into a crouching position while I was walking. No one saw me, but it was rather unsettling.

At first I thought that it was the stress, so I reduced my workload. I quit one choir, then another, took fewer math subjects, and ended my piano lessons. The workload became manageable, but the strange phenomena continued. They even got worse. Most disruptive were not the tics, but the fact that after a night with less than 8.5 hours of sleep I would enter into a state of mental agitation. This state would cause me to be very absent-minded, even though it did seem to boost creativity. The tics would then appear a day later, after a good night’s sleep.

A diagnosis

The symptoms gradually increased. In the meantime, my life changed drastically. I moved twice, finished my studies, and started a PhD. I began to take my religious life seriously and would spend quiet prayer time in a chapel with other people present. During those quiet moments my tics would surface: involuntary movements, sounds, or words. This was noticed, and one day someone proposed that I go and see a neurologist. I went and was told that I had Tourette's syndrome and that I needed to see a specialist in Amsterdam.

The specialist described two treatment options. I could use heavy anti-depressants, which would suppress the tics but also drastically change my character. The second option was "cognitive behavioural therapy", which gave good results for some people. I quickly chose the second option.

Cognitive behavioural therapy

Behavioural therapy started with an inventory of my symptoms. The therapist was amazed that I was not anxious about doing things wrong, because many Tourette's patients develop a sense of guilt about doing anything slightly abnormal, like making involuntary movements. To tell the truth, there was a time when I did become anxious. But with the help of a spiritual guide, I had learned to form a sound moral judgement that gave me inner clarity, and scruples about doing things wrong had nearly disappeared.

The therapist then instructed me on how to avert the tics. I had to sit down quietly, and try to become aware of tickling feelings that indicated energy was gathering for a tic. I would then have to try to delay the tic and if I did that long enough, eventually the tic would dissipate. Doing this regularly would diminish the tics quite considerably, even when not doing the exercise.

I took this as a great opportunity to experiment on myself. Not long before, in a skills training of my PhD program, I had learned to be more aware of what is going on in my body with simple exercises in order to deal with negative emotions and accumulating stress. I had found that very useful. Now I could also use my awareness to attack my illness!

I went at it enthusiastically, and when I saw the therapist one month later, to my own amazement, the tics had been reduced considerably.

The next step in the therapy was learning active relaxation. I was given a CD with a calming voice, instructing me to first tighten and then relax various major muscle groups. Each time the instructor asked to "focus on the feeling of relaxation". This technique would allow me to actively relax the muscles of my body; the relaxed state would in turn reduce the tics. And it worked. It worked so well, that not only did the tics diminish, but my mental agitation was also tempered, a big bonus.

I started to experiment more and I found myself able to relax my organs, including my nerves and brain. I was amazed at this discovery, but it helped me to control the symptoms. At the end of the cognitive therapy, my Tourette's had been reduced from frequent tics and absent-mindedness to something incidental.

I was very grateful.

A few years later my mother, who had been suffering from vague symptoms, discovered that certain magnesium tablets and a specific herbal tea mixture, helped to increase her health. I wondered whether my mother and I might have a similar metabolic dysfunction. So I started taking her supplements. When I did, my body relaxed even more completely than after the exercises. These two food supplements have since reduced the syndrome and made the exercises nearly superfluous.

Beyond genetic determinism

The fact that I am a scientist by no means turns my experience into scientific evidence. Yet experience can be a rich source of inspiration and reflection.

Are organisms determined by their genes and the environment? Well, in this story this is partially true. My stressful environment did help to induce the syndrome and the magnesium helped to reduce its symptoms. There is a hint of a genetic component to the disease in the positive reaction to my mother's therapy. So genes and the environment are important.

But there are more important elements, like "feedback mechanisms". An example of a simple feedback system is a living room with a heating system and thermostat. The design of this system (its "genes") contains information about all its mechanical parts, and the "environment" is defined as everything outside the room. In order to calculate how the room temperature develops in time, it is not enough to know the design of the system and the temperature outside. You also need information about the system itself, like the heat capacity of the air inside, and the current set-point of the thermostat.

The type of air inside, the air pressure, and the set-point are not part of the design of the system or of the environment, but they do influence the way the system behaves. So in a feedback system it is not just genes and environment, but also the system that helps determine what happens.

In my story, feedback mechanisms are important. When a lack of sleep made the syndrome worse, I decided to sleep more, which improved things. When mental unrest led to moral scruples, I sought advice from a spiritual guide who helped me reduce the scruples. When I recognised that a tic was coming, I could consciously defer them. Consciously relaxing my muscles and other parts of my body reduced the symptoms much as the food supplements did. In these feedback mechanisms, the "system that is me" was important.

Modern biology has found many simple examples of biological feedback. For instance, our cells tell our genes to turn on and off (using epigenetic mechanisms); our body maintains a constant blood sugar level; it also indicates when we should eat.

Oxford emeritus professor Dennis Noble recently argued that to understand this completely, we need to fundamentally rethink biological causality, and create “a new synthesis that will reintegrate physiology with evolutionary biology”.

But even this is not the complete story. To understand human biology in all its complexity and mystery, we need to appreciate that the human “feedback system” includes an intellect and a free will. Human organisms are not exclusively biological; to understand them fully, we need to think about mind, body and soul. Biologists need to collaborate with philosophers to clarify this question. But from my experience, it seems that mind and body are both different and one at the same time; they can be distinguished but they cannot be separated. This gives food for thought, but not for reductionism.

Daan van Schalkwijk writes from Amsterdam. He teaches statistics and biology at Amsterdam University College, and is the director of Leidenhoven College, a collegeate hall of residence in Amsterdam. Visit his blog at Science and Beyond 



This article is published by Daniel Bernardus van Schalkwijk and MercatorNet.com under a Creative Commons licence. You may republish it or translate it free of charge with attribution for non-commercial purposes following these guidelines. If you teach at a university we ask that your department make a donation. Commercial media must contact us for permission and fees. Some articles on this site are published under different terms.

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