Genetics and the environment have given rise to much debate throughout the history of psychology. Over the past century, many have defended the position of genetic determinism, while others have said that controlling environmental influences can strengthen any position in an individual.
Over time, the scientific community has resolved the fight by agreeing that these two aspects have influenced equally, half and half other, but what if they don’t? What if the behavior is also due to random and unpredictable factors? This is where the idea of noise comes in.
Stochastic variation in psychology is understood as the variation in personality and behavior that is not attributable to anything or the environment., An idea that we will explain by describing the idea of noise in more depth, giving various examples and relating it to personality traits.
Nothing, atmosphere and noise? Stochastic variation
It’s practically a mantra that various aspects of each, i.e. their individual differences, are a mixture of two factors: genetics and environment.
Some were supporters of genetic determinismIn other words, everyone is born with their genes which have shaped what they should be, without any modification during their life.
Others, on the other hand, depended on the environment, combined with environmental and social influences., To change aspects such as the personality and intelligence of the individual.
Debates over what was most important, whether genetics (“nature”) or the environment (“nourishing”) have intensified over the last century, but by the end of this century it was agreed , in a Solomonian way, of the influence of these two aspects: “fifty-fifty”. Genes and environment have had an equal influence, perhaps one more in some ways and the other in others.
Much of the research has focused on finding out how the environment influences genetics above all else., Under the belief that if all the influences are known, it is possible to predict aspects such as illness and mental disorders, as well as the development of personality, physical and mental. This certainly makes a lot of sense, but the problem is that with research, we have seen that neither the environment nor the environment explains all the variability, especially in the case of genetically identical individuals with the same environment.
Everything that is not attributed to genetics is attributed to the environment. This is how it usually ends in many experiments done with identical twins separated at birth. To the extent that they differ, this it will be because they were brought up separately, having lived in different environments.
The problem is that in identical twins raised in the same environment, raised in the same house, going to the same school, even in the same class, being dressed the same and for a long time and so on, they have differences. Sometimes these differences are very noticeable, like political preference, taste or sexual orientation, how is all this explained? This question has an answer, it is not that it is very elegant but it seems to be worth it for the scientific community: it is because of the noise.
Even in the same individual, there are differences between cell and cell with the same function. This has been observed in cells that exhibit erratic behavior, typical of a tumor cell, while others of the same type do not. When it comes to larger structures, we have differences between the right and left sides of the face, body and brain, and genetics give no explanation for this factor. The fact that the face is not exactly symmetrical could be due to some, say, freakish behavior of the cells that make it up, rather than genetics or the environment.
The sound of the name is not accidental. Scientists called this variable noise because, like sound noise, it is unpredictable and unsystematic. Trying to isolate and measure noise is something one could call at least paradoxical. How do you measure what cannot be predicted? You can play with the genome, you can play with the environment, you can play with physiology, activate certain cells, control stimuli, but you can’t control or change the variation, that’s it.
The strange case of the marbled crab
In the 1990s, a new species appeared in parts of Europe, Japan and Madagascar. A kind of little lobster that lived in all kinds of waters: the marbled crab.
These little crustaceans suddenly appeared, classified as a new species. Apparently, probably in 1995, some individuals of house crab underwent a mutation that allowed them to reproduce asexually, making all their descendants a new species, all females capable of reproducing from eggs without fertilization. Someone escaped one of the mutants, which quickly reproduced and threatened ecosystems.
One of the laws of nature is that organisms that reproduce asexually are very genetically homogeneous. This has advantages and disadvantages. The advantage is that the passage of genes is guaranteed to the next generation, because there are hundreds of replicas of the same genome, but here is the opposite, and is that being all the same, if their genome is not adaptive, some will survive with difficulty in the face of an unfavorable environment. But this was not the case with small crabs.
Despite their genetic uniformity, marbled crabs exhibit differences in color, size, behavior, and even longevity. Although they are clones, they are different, they have diversity. Common sense would tell us that although genetically identical, environmental influences should not be ruled out. Marbled crab raised in a temperate climate may have adapted to accommodate it, while others have done so for cold climates. Nature put the situation on them and they knew how to adapt. But there are too many differences in the same population for this to be the case.
This is a clear example of how genetics and the environment have no control over absolutely everything in an individual’s development. If applicable, one would expect all marbled crab individuals to be equal in a given region, But this is not the case. Even those who live on the same river, with the same environmental factors and the same genetics, have differences. Something in their cells has been fancifully activated to make them different.
Stochastic variation in psychology
Stochastic variation seems to play a very important role when it comes to personality traits. Returning to the above about twins, who doesn’t know identical twins raised in the same house who are like night and day? There are many pairs of monozygotic twins who, despite having the same genome and (almost) the same environment, behave very differently, even have very noticeable differences such as tastes, school performance, sexuality or ideology. Politics.
Apparently during development, brains are organs in which more stochastic variation occurs, i.e. random variation. Some neurons connect, others lose connections, synapses here and synapses there. It sounds like chaos, a situation which it seems is what can bring about big, unexpected changes in an individual’s behavior and personality once they have matured.
There are many genes that have been discovered that allow us to understand both anatomical and behavioral variation in people, which is believed to be the root cause of their individual differences. By altering these genes, one could perhaps measure the importance and capacity of such unpredictable noise.
this has been observed in the experimental setting, but with flies. A 2013 study, conducted by the Hassan Group, revealed this connection and disconnection of random neurons in the brains of these genetically identical insects. The neural connections of these flies varied from individual to individual, although they all had the same genome raised in the same way. They even exhibited intra-individual differences, having asymmetries between the left and right hemispheres. It is these asymmetries, apparently arising from nothingness, which would explain the differences in behavior.
Indeed, on the basis of their experiments, modifying both the genome of flies and seeing their behavior, scientists attribute between 35% and 40% of the behavior of flies to chance, that is to say to noise. The scientists themselves have gone so far as to claim that, depending on the character, noise is responsible for 50% of the variability in personality traits and behavior.
- Masotti, A EL (2000). Genetic, epigenetic and behavioral stochastic variability and individuation process. Imago 45 diary.
- Linneweber, GA, Andriatsilavo, M., Bias-Dutta, S., Bengochea, M., Hellbruegge, L., Liu, G. … Hassan, BA (2013). A neurodevelopmental origin of behavioral individuality in the Drosophila visual system. Science, 367 (6482), 1112-1119.