Anatomy of a fallthe film by French director Justine Triet, winner of the Oscar for best original screenplay, uses the reconstruction of a falling body as a MacGuffin to make a careful dissection of the fall of the romantic relationship of the protagonist couple, Sandra Voyter and Samuel Maleski.
The process of breaking up the relationship that the film describes is no exception, It is a prevalent phenomenon in the world we live in.
The data presents high levels of marriage failure globallywith a general upward trend since the last third of the last century.
For some cohorts of Western marriages, the percentage that ends in divorce after 25 years is 50%, popularizing the claim that “one in two marriages ends in divorce.”
The all or nothing couple
In Triet’s opinion, “the rare thing is that a relationship works, most of them are hell, and the film aims to delve into that hell.”
Certainly, negative divorce statistics underestimate the number of relationships that are unhappy. Maybe most of it is hell. However, other relationships are not only lasting success: They are better than relationships have ever been.. That dichotomy – majority failure or exceptional success – seems to summarize the state of contemporary marriage in the West, which It has been called all or nothing.
Scientific studies establish that couple relationships decline, that is, the quality or satisfaction of the relationship declines over time on average. Some couples – the successful ones – they stop their fall and stabilize at satisfactory levels forever. But a majority of relationships fall slowly until they come to an end. a state of such discomfort that the breakup is a matter of time.
Understanding these disparate falls, how and why they occur, is the objective of the science of relationships.
The second law of the thermodynamics of feelings
The psychology of relationships says that maintaining a relationship over time requires effort. This is what has been called the second law of thermodynamics of romantic relationships.
The all-or-nothing theory suggests that successful couples require, in addition to compatibility, a significant investment in time and energy. These couples manage to reach a high level of satisfaction, compared to those who are not capable of making the required effort and fall, like that of Samuel and Sandra in Triet’s film.
Why do some couples stop the decline and stay happily ever after? Like that of Samuel and Sandra, all couples initially belong to the same class: that of lovers who want to be together and happy forever. If it is also assumed that They are highly compatible and willing to put in the effort Together – they are called homogamous couples – they form a relationship that can be called Adam and Eve type.


Fall to breakout level vs. fall of success. The second is controlled by appropriate levels of overexertion. The more efficient member of the pair must make greater effort.
The Adam and Eve model
The mathematical analysis of the Adam and Eve model confirms the all or nothing theory.
Dynamic systems are the mathematical tool to understand the evolution of a variable over timein the case of romantic relationships, the feeling of love or feeling in the couple. The fact that effort is necessary to sustain the relationship turns the sentimental dynamic into a dynamic system controlled by effortwith the aim of lasting forever.
The theory of controlled dynamic systems shows that a successful couple requires a demanding effort, above the favorite level (the one that is preferred to perform). a priori), which is also difficult to sustain over time. Those who exceptionally manage to maintain that effort gap also achieve a fulfilling happy relationship. It happens, however, that It is easy for them to fail in the attempt.
Mathematics of an asymmetric fall
There are times when a relationship is chaos, sometimes you fight alone, sometimes accompanied by the other, and sometimes against the other. This is how Sandra Voyter expresses it at one point in Triet’s film. That passage gives an idea of how difficult it can be to govern the chaos of every relationship.
Samuel and Sandra’s relationship It has ingredients in common with any other relationship: the starting point is very high –the feeling is on the cusp –, there is a common approach that the relationship will never end, both are willing to contribute to the happiness of the relationship with an individual effort that they must manage separately, and both know that a disagreement is likely to occur. shock either external disturbance that alters the state of things.
It’s known that Homogamous couples, avatars of Adam and Eve, are more stable than those who are not. In general, couples are made up of members who are different with respect to some trait, for example, socioeconomic, cultural or religious. In this case they are called heterogamous.
The most basic heterogamy consists of the different efficiency of the members to transform effort into feeling or happiness of the couple. This disparity may mean an asymmetry in the respective levels of efforts to contribute in a successful relationshipwhich also turn out to be superior to the favorites, as in the case of homogamous couples.
This is what happens in the relationship between Samuel and Sandra: Samuel expresses at one point in the film that things are unbalanced between them, and Sandra replies, convinced that, from the start, does not believe in the idea of equal reciprocity in a couple, which he considers downright depressing. She seems convinced that the couple’s effort levels should not be equal. An idea that is likely the subject of much debate in all relationships.
Who puts more?
Our recent computational models of control of the dynamics of asymmetrically efficient couples They allow you to simulate the evolution of happiness in the relationship, both in less uncertain environments and with different levels of uncertainty. The simulations suggest that the two members must exert themselves asymmetrically, with Sandra right in her reply.
In the film, in a typical scene of negative couple dynamics, Sandra and Samuel they reproach each other for the efforts they make or not to sustain the relationship. They both have things to say, as in many real couples. Also in some passage of the script it is implied that Samuel has made or makes more effort than Sandra for her relationship with her partner and family. Our analysis shows, perhaps surprisingly, that The most efficient member, transforming his effort into mutual happiness, must make greater efforts to sustain the relationship.. In the movie, that’s Samuel.


Efforts must increase from shock to recover from the impact and stop the fall. The overexertion of the most efficient (pink curve) should increase relatively more in the recovery period. The combination of weakened levels of feeling and the cost of additional overexertion over a prolonged period can lead to an unsustainable situation, particularly for the most efficient, and cause the relationship to fall into free fall.
An external impact
The analysis also suggests that when the couple is subjected to a stressful episode due to an unexpected cause, both members must increase their effort gap. But also, the gap of the most efficient again should increase relatively more. Precisely, Sandra and Samuel’s relationship is subject to tremendous misfortune whose impact affects the crux of the story for a long time. That’s why Samuel feels much more stressed than Sandra.
Mathematics offers an outcome in line with the plot of the film: the continued gap of greater overexertion that the most efficient member must make, increased even more in a prolonged period of sentimental crisis, can lead to a feeling so unbearable that it is only resolved with the fall of the relationship until it breaks. In the case of the film, also, with Samuel’s fall into the void.
José-Manuel Rey, Professor of the Faculty of Economics and Business Sciences, Complutense University of Madrid and Jorge Herrera de la Cruz, Contract Professor Doctor Department of Mathematics and Data Science, CEU San Pablo University
This article was originally published on The Conversation. Read the original.