Newton’s pendulum: in psychotherapy it is played with the law of conservation of momentum

Newton’s pendulum: in psychotherapy it is played with the law of conservation of momentum

It often happens to all of us to put in place behaviors, to experience emotions, to produce thoughts without realizing what specific stimuli initially elicited these mechanisms. Newton’s pendulum with its 5 spheres helps us to better analyze this aspect of human functioning.


 One of the reasons why people spontaneously turn to a mental health professional is because they find themselves experiencing emotions, having thoughts and acting behaviors that they do not fully recognize as the result of their will or at least consider them unpleasant, uncontrollable and not in in line with the image they have of themselves.

Many people, for example, turn to the psychologist because they often engage in destructive and aggressive behaviors both self and straight. These patients report loss of control of their excessive and often unmotivated impulses. After this check, the patient reports emotions of disappointment, discomfort and confusion of thought precisely because of the discrepancy between his way of understanding himself as a person and the behavior just put in place. This cognitive dissonance and the emotions that derive from it also lead to a significant reduction in self-esteem and above all to a lowering of self-efficacy (belief regarding one’s ability to produce specific behaviors useful for achieving a desired goal) since we have not been able, once again,

These patients have the impression that in that particular moment in which they lose control they are pushed by an ungovernable force and by a state of completely disregulated emotional activation. Both the patient and the psychologist are therefore committed to cooperating to discover the true nature of this “force”.

One day, at the end of a session with a patient with problems similar to those described above, reflecting I still echoed the questions that the patient had asked himself and had asked me during the session just ended, questions like: “how is it Is it possible that I lost control over such nonsense? Is it normal that in a few moments my vision became clouded with anger and then after not even five minutes I almost can’t remember why I was so angry? “

As I thought about these questions I hypothesized that sometimes the patient happened to easily forget the “reason” of his anger simply because what he referred to was not the real reason, but probably only the last link in a long chain of phenomena interior. While I was thinking about all this, I was playing, as often happens to me, with an object resting on my desk, the so-called “Newton’s Pendulum”. As I watched the spheres swing and listened to the typical ticking caused by their collision, I was surprised to think of a strange but nice analogy between the functioning of that instrument and the “functioning” of the patient who had just greeted me.

Before clarifying and, I must say, justifying such an analogy, however, I want to make sure that the reader is well aware of the instrument I am talking about (Newton’s pendulum or Newton’s marbles) and above all to try to provide him with superficial but fundamental psychological concepts.

I think most of us have seen this object at least once. We are talking about a device composed of various metal spheres (usually 5) all having the same mass and each suspended by two wires. The spheres are in contact on the same horizontal line and can move in the vertical plane.

It is used to illustrate the laws of conservation of momentum and mechanical energy.

With the spheres stopped, the first sphere is raised, keeping the threads with which it is suspended taut, and it is dropped. It will hit the ranks of the others and it will be observed that the first one stops, the intermediate ones do not move, and the last sphere starts upwards, reaching the same height from which the first one started, and so on. This “hit and answer” could potentially go on indefinitely if only external factors did not intervene, such as the friction of the air which progressively slows down the movement of the spheres until they stop.

In fact, remember that the principle of conservation of momentum states that:

Two observations are particularly interesting to me about the functioning of Newton’s pendulum and both will be taken up later as elements that justify my bizarre analogy:

The human being is a system certainly not isolated and therefore never independent of the context in which he finds himself. External environmental and social factors have a decisive influence on our thoughts and behavior.

The neo-cortex has endowed us human beings with the finest and most advanced tools that allow us to read live the environmental and social signals present in the environmental context and “matcharli” them with personal, cultural and moral information stored in memory.

This ability is evident in what are called cognitive scripts or more or less complex behavioral patterns that, more often than not implicitly, we implement in a specific and determined order in order to adapt to a given context. A trivial example is when we go to the restaurant and approach the table, first we don’t ask the waiter for the bill, but we probably take off our jacket and take a seat. This behavior, together perhaps with the fact that (if the restaurant is a very refined 3 Michelin Star restaurant) we respect a particular dress code, it does not only depend on the proper functioning of the procedural memory, but also informs us about our ability to recognize,

But the neo cortex is not the only brain system that evolution has provided us with. With MacLean (MacLean, P. 1973) we could symbolically divide our brain system into 3 parts:

We have already mentioned the neo-cortex.

As for the limbic system, we can synthetically say that it is made up of some structures below the cortical: the olfactory bulbs, the hippocampus, the amygdala, the cingulate gyrus, the anterior thalamic nuclei and the limbic cortex. It supports various psychic functions such as the processing of emotions, motivation, learning, memory and attachment.

The reptilian brain resides in the diencephalon, in the midbrain and in the initial part of the telencephalon and deals with innate needs and instincts: territoriality, predation, exploration of the territory and procreation. The autonomic nervous system consists of anatomically and functionally distinct but synergistic portions: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system.

It has the function of regulating the homeostasis of the organism and is a neuro-motor system that cannot be influenced by the will that operates with precisely autonomous mechanisms, related to peripheral reflexes subjected to central control. As far as SNA is concerned, the differentiation between two types of vagus nerve, the myelinated and the non-myelinated one, proposed by Stephen W. Porges (Porges, SW. 2014) in his polyvalent theory, is worth mentioning.

Because in this way it is easier to understand which structure or function is inhibited, hyperactivated, altered, compromised or more simply to understand what, if any, there is the hierarchy of internal functioning between these structures.


This division obviously serves a purely explanatory purpose, but in reality all the anatomical-functional structures that make up our central nervous system are closely connected and work synergistically.

This division is also very useful for me to pick up the thread of the discussion.

Here, now let’s do an imaginative exercise. Let’s imagine that each of the 5 pendulum spheres represents something:

The spheres were thus ordered according to the speed with which the different brain systems tend to activate in situations perceived as dangerous and / or threatening.

We now know therefore that a stimulus, external or internal, objectively dangerous or subjectively interpreted as such can trigger an immediate and complex reaction that only in the final analysis (and not even every time) could it reach our awareness as in the case of shutdown cortical. In these situations we could experience emotions, produce thoughts and implement very complex behaviors that therefore in retrospect seem to us in all respects devoid of valid motivation or out of proportion to what we explicitly experienced (Imm. 1)

Im.1 – Newton’s pendulum as a metaphor for psychic functioning

This lack of awareness of the close interdependence between stimulus and behavioral response is well represented by the example of Newton’s pendulum and in particular by the first of the two observations that I proposed above, or that the first and last sphere are not they also touch if it is the energy of one that produces the movement of the other.

The point is this, as it happens in Newton’s pendulum where the fifth sphere performs a movement without “knowing” that it takes place thanks to the energy produced by the movement of the first, in the same way it often happens to us too to implement behaviors without realizing what specific stimuli initially elicited this behavior. The two spheres do not touch each other yet we see that they influence each other greatly. In therapy, the goal is precisely to understand how our reactions are the result of a complex elaboration process that always starts from a stimulus.

The second observation to which the Newton Pendulum gave inspiration was the following:

We have already said that the human being is not an isolated system just as Newton’s pendulum is not isolated, unless the latter is placed inside a bell under vacuum without sending him any type of vibration. Yet we have seen that in the psyche of the human being there is a principle superimposable to that of conservation of momentum and mechanical energy. We observe it every time a person is aware, determined and determined to want to modify a certain behavior or thought and then punctually ends up failing despite his conscious and sincere commitment.

Some in the past called it “eternal return”, “compulsion to repeat”, more recently “interpersonal cycles”, “life scripts”, “early maladaptive patterns”, etc. Today, above all thanks to neuroscience, we know that the basis of this principle is always there

The term danger is quoted to underline once again the fact that the danger does not necessarily have to be real or current, but it is sufficient that it is able to activate memory traces associated with situations lived or imagined where you have subjectively experienced feelings of threat and / or danger. Here it is fundamental to specify that by subjective feeling of threat / danger we do not mean only the physical one but, indeed almost always, a threat / danger to one’s identity image, one’s beliefs and values ​​and principles. On that or, more often, those past occasions, the person will certainly have acted on the mental and behavioral responses that have contributed to his physical and identity survival.

The goal of the therapy is therefore to do what the air does with the spheres of Newton’s pendulum, that is to interfere with the perpetual propagation of energy and motion, making the system no longer isolated. The friction of the air against the spheres must be replaced in therapy with continuous and systematic self-observation thanks to the help of the psychologist and the techniques he will recommend.

Observing yourself as “objectively” as possible allows you to systematize internal and external events, to archive them, to recognize their repetitiveness, to produce any cause-and-effect links and therefore to prevent their manifestations or to reduce the scope of those considered more problematic.

For quite some time, or perhaps forever, the external stimulus subjectively considered to be threatening will continue to elicit a hyperactivation / hypoactivation of the SNA and also that of the limbic-subcortical circuit, consequently causing an emotional activation or hypo-activation which, however, , if well recognized and accepted, it can be regulated by means of a concomitant cognitive retro-action (cognitive reappraisal) which, together with possible various techniques for regulating the state of physiological activation (arousal) will produce an increase in the mastery understood as perception of mastery that is, to feel that you have control over your mental state.