Handedness is one of the most intriguing human behaviors. Even though it may seem normal to write using your right or left hand, there are a lot of complex factors that lead to this trait. The majority of the world’s population is right-handed, which makes lefties somewhat. There being so many misconceptions that revolve around this topic, here are the actual reasons why some people are left-handed.
Left Handedness According to Scientists
Scientists point out two main factors – genetics and environment. Hand preference is often identified during the early stages of childhood. Without training, a child automatically prefers using one hand over the other. This may be observed by looking at a child’s hand when eating or playing.
For a long time, scientists have not been able to identify the biological causes of left- or right-handedness. However, recent studies have shown that left-handed people have dominant right sides of the brain. On the other hand, right-handed people have dominant left sides of the brain, a concept known as brain asymmetry. The idea of brain asymmetry develops as the fetus grows inside the womb and is further linked to specific genes.
It was initially perceived that one particular gene was responsible for left-handedness. However, scientists have discovered that up to 40 genes may result in this trait as they are responsible for determining brain asymmetry. In the case of lefties, the genes picked the right side of the brain to be more dominant and in charge of movement.
Do Left-Handed Parents Result In Left-Handed Children?
Because genes are passed down through generations, left-handed parents will most likely give birth to left-handed children. Also, if the children grow up in the same environment as their parents, they will likely pick up this trait.
What Is The Probability of a Person Being Left-Handed?
Genes aside, some scientists believe that handedness could result from chance. As the brain of the embryo develops, there are a lot of variants that can lead to the birth of a left-handed baby. This makes sense in instances where both parents and even grandparents are righties, yet the baby comes out as a lefty.
Still in families, left-handedness is more common in twins than in the general population. Because twins share a lot of genes, there is a high chance that they may both be lefties, irrespective of whether they are identical or fraternal. This doesn’t come as a surprise because twins are mostly mirror images of each other.
Another unique factor that has been associated with left-handedness is stress during pregnancy. A study conducted by British scientists discovered that expectant mothers who were under heavy stress gave birth to left-handed babies. Most children born through a stressful pregnancy would touch their faces mainly with the left hand, thus indicating their preference during the early stages. Further studies also show that babies born by older mothers tend to be left-handed.
How the Environment Can Affect a Person’s Handedness
The environment is also a key determiner of handedness. There are cultures, such as some African tribes, that shun left-handedness by associating it with evil. Although this is mostly a thing of the past, a left-handed child born in this environment may be forced to switch to their right hand. This is heavily discouraged in modern times but has been a contributing factor.
Also, an injury on the right hand can force someone to make their left hand dominant. Therefore, as much as genes contribute to handedness, the environment can alter this trait.
Factors That Don’t Affect a Person’s Handedness
While discussing what causes left-handedness, it’s crucial to highlight some of the speculations that have been proven to be inaccurate. It’s not strange to come across people or posts saying that ultrasounds, birth complications of high levels of fetal testosterone cause left-handedness. These are all false.
Starting with the latter, scientists were able to rule out that testosterone levels do not affect a child’s handedness, and neither do ultrasounds. As for birth complications, even before a baby is born, they already have a hand preference. This is evident when they are sucking a thumb while still in the womb. If they suck the right-hand thumb, then they are righties, and vice versa.
Conclusion
Scientists have just started figuring out what causes left-handedness. Therefore, there is very little information about its causes and contributing factors. With time, we may narrow down to specific causes. That said, this trait is not a superpower. Yes, being a lefty has its perks, especially in interactive sports such as boxing and soccer, because it comes with an element of surprise. However, it doesn’t make one more creative or artsy.
There are a lot of speculations out there regarding left-handed people which are untrue. Let’s use this example: if left-handed people were as common as right-handed people, then there wouldn’t be any “advantages”. From an overall point of view, handedness doesn’t matter.