What is the advantage of being right handed?

I heard on the radio that they have found a gene that contributes to being left handed.
Being left handed myself, I have always been interested in this subject and, in the past, have read many theories about right and left handedness (none of which I can remember).
For this thread, I am particularly interested in the evolutionary advantage of being right handed. Does anyone have a theory on this? I find it hard to believe that 90% of the population is right handed because of a genetic fluke?

What’s the advantage of being handed at all?

Exactly. Why not 50-50?

Dedicating resources to handedness is very taxing on the brain and most tasked don’t require more than one fully competent hand.

An intersting point but it doesn’t answer the question. We could still have 50% right handed and 50% left handed.

There’s not an evolutionary explanation for everything. It’s not baseball or anything, it doesn’t have to make sense. We’re not going to discover some canyon that humans gave birth in that only right-handed people and some exceptional left-handed people could escape. There wasn’t any fierce predator that was particularly ticklish on its left side, spurring us to evolve to be right-handed.

But evolution is a lot more subtle than absolute live-or-die watersheds dependent upon a singe decisive factor. It’s a statistical process. Any difference between organisms is quite likely to confer at least some small advantage or disadvantage, and that’s a ll it takes.

I wouldn’t say that. I would say that any difference between organisms which does confer even a minute advantage or disadvantage will likely be either selected for or against (respectively; assuming the trait is also heritable). But it’s not the case that every trait will (or is even likely to) confer said advantage/disadvantage.

“All it takes” is really a match up between trait and environment.

And I doubt that handedness comes into play in an evolutionary sense. Could just be an ontogenetic happenstance. Indeed, see this article: Human Handedness and Scalp Hair-Whorl Direction Develop From a Common Genetic Mechanism. Apparently, both traits are rooted in the asymmetric lateralization which occurs during development – that is, the two sides of the body do not develop identically, leading to such subtle differences. Exactly why/how this is the case has not yet been determined.

It’s possible that right-handedness is a product of another evolutionary advantage earlier on. Much as the things that eventually became wings.
ETA: Just thought of an advantage of handedness, it builds the muscles on that side to make you stronger and increases neuromusculature connections.

Our brains are not symmetrical, and one half of your brain controls the opposite half of your body. It’s not difficult to imagine that because of this there may be a bias towards which side of your body become dominant.

This paper pushes the theory that it’s tied to our language-processing capabilities, which are located in the left hemisphere. They theorize that human ancestors originally developed hand signals for communication before evolving the ability to use speech to communicate. Because the language-processing capabilities are in the left hemisphere, we’d be biased towards using our right hands to communicate.

Why not? The only reason why trait A is passed down, rather than trait B, is that trait B creates a disadvantage (or death) by the time a person is old enough to reproduce. Right-handedness may be dominant due to nothing more than an evolutionary fluke, like many other traits.

It seems to me that having one hand “specialize” in fine hand/eye detail work is more efficient and therefore evolutionary-wise, “better” than having two hand that are only so-so.

On edit-- after reading **Darwin’s Finch’**s post more closely— humans are not perfectly symmetrical. After all- our heart are mostly (but not always) more on the left side of our chests.

Perhaps babies tend to turn toward the beating heart at some point during gestation and this causes one side’s limbs (or brain hemisphere) to develop differently.

Here’s an interesting article about brain asymmetry in animals. In seems quite common for animal brains to assign certain tasks and duties to one side of the brain or the other, rather than sharing them 50-50.

Here is an edited version of my last paragraph from my last post because my edit-ability timed-out:

Perhaps babies tend to turn toward the beating heart at some point during gestation and this causes one side’s limbs (or brain hemisphere) to develop differently. (I don’t offer that as an actual hypothesis-- just an example of how our asymmetricalness could perhaps lead to a preponderance of right-handedness.

Gene for left-handedness is found

Here’s one advantage to having one particular handedness be more common: Tools. A tool designed to be used in the right hand generally won’t be as easy to use in the left hand. So for a tool-using species like us, there’s good reason to go with the crowd.

Not that this is a complete explanation, of course, since non-tool-using species often show a bias as well.

You may be right, although I’d bet that outside of the relevant academic fields, we generally underestimate the selectability of differences - because evolution is commonly thought of in terms of gross, black and white failure or success to survive or reproduce.

I’d give my right arm to be ambidextrous…


There is a certain level of heredity involved in handedness, has there been any instances of isolated conclaves of humans being overwhelmingly left handed?