Since its inception, psychology has been a science that attempts to explain human behavior.
Since its inception, psychology has been the science that has tried to find explanations for why people behave so differently.
After decades of research and warmth discussions about whether genetics or the environment are more influential in shaping a person’s personality and behaviorThe already more than famous debate of “nature versus culture” has been overcome, giving the two factors more or less the same importance.
In our genes are some of the causes that make us look more like our parents than our neighbor, but, in turn, the neighborhood we live in or the region we live in also influences our behavior.
Overcoming the debate was about understanding something that is happening in all families. Although the siblings are quite similar, there is always something that sets them apart. His genotype, although not exactly the same, cannot be. The environment shouldn’t either, because all family members receive the same influences from it, right?
In this article, we will discuss an aspect that has often not been taken into account in understanding how the environment influences each of us in relation to our loved ones. Let’s see how the shared environment differs from the unshared environment..
Differences between shared and unshared environment: a summary
Still tragically, the study of behavior, intelligence and personality in identical twins separated at birth has been one of the most beneficial situations in understanding the extent to which certain phenotypic traits are hereditary and dependent on l environment in which we grow up. The premise is that if two monozygotic twins, i.e. two genetically speaking clones, live in different houses, the aspects they share will be due to their genetics, while what they differ will be due to the environment and / or their interaction with the genotype of these individuals.
Thomas Bouchard is an American psychologist and geneticist who has studied pairs of newly born twin twins. In its project, the Minnesota Study of Separately Raised Twins investigated how genetics and environment influence the personality of separately raised twins. In this type of study, the genetic importance is very important, but we can see that the environment influences the behavior of people.
The environment is understood as the set of aspects external to the person which may or may not exert a certain influence on personality, cognitive abilities and behavior of the individual. Bouchard-style studies assume that breeding in different houses involves different environments, while doing it in the same tends to mean breeding in the same environment.
However, for quite some time now and even raised in Bouchard’s own study, the possibility has arisen that living in the same house and, therefore, growing up with other biological siblings does not mean that the same environmental influences are received. The reason is the obvious fact that siblings are not equal in terms of behavior or abilities.
It is true that the brothers of the same family did not inherit the same genes each of them, otherwise we would not speak of dry brothers, but of identical twin brothers. However, the genetic basis is there, and that should imply that there was very little difference between siblings, which is rarely the case.
Even between monozygotic twin brothers raised in the same house, there are differences. The differences must necessarily be explained by the environment, but having been raised in the same household, how is it possible that differences in behavior also occur?
This is where we talk about the shared environment and the non-shared environment, two factors within the concept of environment or environmental influences that allow us to understand the differences and similarities of members of the same. family. Let’s take a closer look at what these two concepts mean.
Time and again it has been taken for granted that living in the same family, the same house, the same neighborhood means receiving the same environmental influences.
Indeed, this definition corresponds to what is understood as a shared environment, also called family, that is to say the aspects of the environment which are shown in the same way to all the members of the same family. and which, for so many things, make they look more alike.
To understand it more clearly, an example of a shared environment would be the very house in which siblings live. By living in the same house, they all receive the same influence from him.
Another aspect considered as a shared environment would be living in a bilingual region and, therefore, siblings would be able to speak two languages with the same fluency as the environment requires. By mastering both languages, they would have the same type of cognitive stimulation from the environment in which they were raised.
As a third example, it would be the socio-economic level of the family. If it is the case of living in a wealthy family, none of the family members will suffer from any situation where there is some kind of nutritional deprivation due to the inability to buy food.
Since all the members of the family stay in the same environment, therefore shared, it is not possible to explain with this type of environment why there are differences between brothers and sisters.
The unshared environment, also called the individual environment, is understood in terms of influences rather than in terms of the environment itself. It would be the set of factors external to the person which are interpreted differently according to each member of the same family.
Coming back to the case of monozygotic and therefore genetically identical twins, the unrequited environment would be the one that would explain why two twins of these characteristics, raised in the same place, can behave differently.
There are various environmental aspects that can exert a different influence on siblings. For example, a twin brother may have suffered from more influenza in their lifetime or have been in a car accident.
Further, as an unrequited environmental factor is found the different treatment by parents that may be given. It is not uncommon for couples of twins to claim that they are the older of the two and who, because of this little detail, behave more maturely or think they should have more rights over the other., And l The family environment behaves by promoting this.
Another very important aspect, always taking monozygotic twins as an example, is education. Although at home they receive the same discipline, at school it is common that they do not attend the same class and therefore have different classmates and teachers.
Family events can be experienced differently between siblings. For example, the death of a loved one, which is sad in itself, can be experienced in a much more grieving way by one of the siblings compared to the others and affect more deeply.
Beyond biology and genes
The shared and unrequited environment, in addition to genetics, is at the root of the way people are. It should be noted that research indicates that the influence of the two types of environment is different according to the stage of evolution. During childhood, the shared or family environment acquires a fundamental role, being something that very strongly shapes the person. Over time, the influence of the family environment collapses, acquiring greater significance for the unrequited or the individual.
In fact, as an example, a point of view very common among adults when asked what they think most influences a person’s way of being is what the genetic inheritance, as well as his experiences (often leaving as one was raised) are factors to consider that explain the behavior of each.
Obviously, this does not mean that extremely harmful children’s situations, such as situations of abandonment and abuse, do not influence how a person can become an adult. However, leaving out the extreme cases, more importance is usually placed on the heritability with which stimuli of individuals that have been received throughout their lives.
- Bouchard, TJ, Jr., et al. (1990), “Sources of Human Psychological Differences: The Minnesota Study of Separated Twins”. Science, vol. 250, no. 4978, p. 223-228.
- Plomin, R. and Daniels, D. (2011), “Why are children in the same family so different from each other?”. International Journal of Epidemiology, vol. 40, no. 3, p. 563-582.
- Plomin, R. et al. (2001), “Why are children of the same family so different? Unrequited environment a decade later. Canadian Journal of Psychiatry. Canadian Journal of Psychiatry, Vol. 46, no. 3, p. 225-233.
- Plomin, R. (2011), Commentary: Why Are Children in the Same Family So Different? Unrequited environment three decades later ”. International Journal of Epidemiology, vol. 40, no. 3, p. 582-592.