6.8.2. How It Works
By doing the previous tests, you can see that you can still use your off-hand for some things and that it is easier to use your off-hand for some things than for other things. Most people have some things for which they use their dominant hand, some things they may use both for, and some for which they use their off-hand.
So, in a sense, describing people as left-handed or right-handed is limiting because it puts them into only one category and ignores the extent to which they may be in that categoryor in between the two. This is why, of course, we used behavioral measures to work out the handedness quotient, rather than just asking people.3
Handedness is only weakly genetic. The child of two left-handers has a 45-50% chance of being left-handed, and thus handedness must partly be to do with how the child is brought up as well, so we know that there is a large nongenetic influence on whether you turn out to be a left-hander. Evidence also suggests that left-handedness may be associated with neurological insult in the womb or during delivery.4
If you try the test out on a few people, you will see that left-handed people more easily use their right hand than right-handed people use their left hand. In part, this is probably because our right-handed world forces left-handers to learn to use their right more, and it could also be for deeper reasons to do with brain lateralization as well.
Taken from : Mind Hacks
